Toggle Side Panel

Shopping Cart

No products in the basket.

Shopping Cart

No products in the basket.

Close search
Home / DTC / P1115 — Coolant Temperature Sensor Plausibility

P1115 — Coolant Temperature Sensor Plausibility

Detailed page for trouble code P1115.

34,405codes
59brands
11,914generic
22,491specific
All codes P-codes (Powertrain) B-codes (Body) C-codes (Chassis) U-codes (Network/User) Tesla Alerts
Reset
Code

P1115

BMW P — Powertrain

Coolant Temperature Sensor Plausibility

Brand: BMW
Type: P — Powertrain
AI status
Completed
ready
Completed 100%
Page language: EN

Causes

  • Faulty engine coolant temperature (ECT) sensor
  • Open/short or intermittent wiring between sensor and ECU
  • Poor connector connection or corrosion at sensor or ECU
  • Stuck or faulty thermostat causing abnormal coolant temperature behavior
  • Air pocket or low coolant level causing incorrect readings
  • Incorrect sensor installed (wrong type or resistance curve)

Symptoms

  • Illuminated MIL / Check Engine Light
  • Difficult cold starts, extended cranking or poor idle until warm
  • Erratic engine temperature gauge or incorrect dash temperature readings
  • Reduced fuel economy or rich/lean running from incorrect fueling
  • Cooling fan not operating properly or running continuously
  • Possible overheating or poor heater performance

What to check

  • Retrieve freeze frame and live data for ECT, ambient air temp, intake temp and coolant temp during cold start and warm‑up
  • Check for additional related DTCs (P0115, P0116, P0117, P0118, thermostat codes)
  • Visually inspect ECT sensor connector and wiring for corrosion, breaks or damage
  • Measure ECT sensor resistance vs known temperature chart or manufacturer specs
  • Backprobe sensor signal and measure voltage reference and ground with ignition on
  • Verify coolant level and check for air in cooling system; pressurize and inspect for leaks

Signal parameters

  • Sensor type: typically a negative temperature coefficient (NTC) thermistor; resistance decreases as temp rises
  • Typical signal voltage range: 0.0–5.0 V (varies by model and sensor); at cold 2.5–4.5 V, at warm 0.1–1.5 V (manufacturer-specific)
  • Reference supply: usually stable 5 V reference from ECU
  • Expected behavior: smooth monotonic change with temperature and consistent with ambient/engine conditions during warm‑up

Diagnostic algorithm

  1. Verify: Read code, note freeze frame, and check for related codes. Clear code and attempt to reproduce.
  2. Observe live data: With a scan tool monitor ECT, ambient air temp and intake air temp during cold start and warm up. Look for implausible jumps, flatlines or values inconsistent with ambient.
  3. Visual inspection: Check sensor connector for corrosion, bent pins, water intrusion, and secure mounting. Inspect wiring to ECU for damage.
  4. Electrical tests: With ignition on, backprobe: verify ECU 5 V reference present, good ground, and that sensor signal voltage moves with temperature. Check for shorts to power/ground.
  5. Resistance check: Remove sensor and measure resistance at known coolant temperatures (compare to BMW spec or typical NTC curve). Replace if out of spec.
  6. Functional check in‑vehicle: If safe, warm engine and observe ECT change. If ECT reads incorrectly but sensor bench test is good, suspect wiring or ECU.
  7. Cooling system check: Verify coolant level, bleed air from system, and confirm thermostat opens at correct temp — a stuck thermostat can create implausible sensor behavior.
  8. Repair: Replace sensor or repair wiring/connectors as required. If wiring and sensor are good consider ECU/software update or module fault diagnosis.
  9. Confirm: After repair, clear codes and road test to verify correct temperature behavior and that P1115 does not return.

Likely causes

  • Damaged sensor or internal sensor drift
  • Damaged harness (chafing, pinched, water intrusion) between sensor and ECU
  • Loose or corroded sensor connector
  • Thermostat stuck open/closed affecting temperature ramp
  • Low coolant or entrapped air in cooling system

Fault status

⚠️ Status
The engine control module detected an implausible engine coolant temperature signal. The coolant temperature reading is inconsistent with expected values or other sensors. Possible causes include a faulty coolant temperature sensor, wiring/connector faults, thermostat or cooling system issues, or a control module problem.
🟡 Repair difficulty: Medium
⏱️ Diagnostic time: 1.0-3.0 hours

Similar codes

P0115 P0116 P0117 P0118 P0125 P0128
Repair manuals

Manual library for BMW

479

Browse 479 BMW manuals: repair procedures, diagnostics, wiring diagrams, component locations, service data and Labor Times by year, model and trim.

BMW

Your experience will help others
+100 karma for a short comment :)
Keep it short and practical. Up to 500 characters.
Send to email
Code

P1115

BUICK P — Powertrain

Engine Coolant Temperature (ECT) Sensor Circuit Intermittent High Voltage

Brand: BUICK
Type: P — Powertrain
AI status
Completed
ready
Completed 100%
Page language: EN

Causes

  • Faulty engine coolant temperature (ECT) sensor
  • Open/short or intermittent wiring between sensor and ECU
  • Poor connector connection or corrosion at sensor or ECU
  • Stuck or faulty thermostat causing abnormal coolant temperature behavior
  • Air pocket or low coolant level causing incorrect readings
  • Incorrect sensor installed (wrong type or resistance curve)

Symptoms

  • Illuminated MIL / Check Engine Light
  • Difficult cold starts, extended cranking or poor idle until warm
  • Erratic engine temperature gauge or incorrect dash temperature readings
  • Reduced fuel economy or rich/lean running from incorrect fueling
  • Cooling fan not operating properly or running continuously
  • Possible overheating or poor heater performance

What to check

  • Retrieve freeze frame and live data for ECT, ambient air temp, intake temp and coolant temp during cold start and warm‑up
  • Check for additional related DTCs (P0115, P0116, P0117, P0118, thermostat codes)
  • Visually inspect ECT sensor connector and wiring for corrosion, breaks or damage
  • Measure ECT sensor resistance vs known temperature chart or manufacturer specs
  • Backprobe sensor signal and measure voltage reference and ground with ignition on
  • Verify coolant level and check for air in cooling system; pressurize and inspect for leaks

Signal parameters

  • Sensor type: typically a negative temperature coefficient (NTC) thermistor; resistance decreases as temp rises
  • Typical signal voltage range: 0.0–5.0 V (varies by model and sensor); at cold 2.5–4.5 V, at warm 0.1–1.5 V (manufacturer-specific)
  • Reference supply: usually stable 5 V reference from ECU
  • Expected behavior: smooth monotonic change with temperature and consistent with ambient/engine conditions during warm‑up

Diagnostic algorithm

  1. Verify: Read code, note freeze frame, and check for related codes. Clear code and attempt to reproduce.
  2. Observe live data: With a scan tool monitor ECT, ambient air temp and intake air temp during cold start and warm up. Look for implausible jumps, flatlines or values inconsistent with ambient.
  3. Visual inspection: Check sensor connector for corrosion, bent pins, water intrusion, and secure mounting. Inspect wiring to ECU for damage.
  4. Electrical tests: With ignition on, backprobe: verify ECU 5 V reference present, good ground, and that sensor signal voltage moves with temperature. Check for shorts to power/ground.
  5. Resistance check: Remove sensor and measure resistance at known coolant temperatures (compare to BMW spec or typical NTC curve). Replace if out of spec.
  6. Functional check in‑vehicle: If safe, warm engine and observe ECT change. If ECT reads incorrectly but sensor bench test is good, suspect wiring or ECU.
  7. Cooling system check: Verify coolant level, bleed air from system, and confirm thermostat opens at correct temp — a stuck thermostat can create implausible sensor behavior.
  8. Repair: Replace sensor or repair wiring/connectors as required. If wiring and sensor are good consider ECU/software update or module fault diagnosis.
  9. Confirm: After repair, clear codes and road test to verify correct temperature behavior and that P1115 does not return.

Likely causes

  • Damaged sensor or internal sensor drift
  • Damaged harness (chafing, pinched, water intrusion) between sensor and ECU
  • Loose or corroded sensor connector
  • Thermostat stuck open/closed affecting temperature ramp
  • Low coolant or entrapped air in cooling system

Fault status

⚠️ Status
The engine control module detected an implausible engine coolant temperature signal. The coolant temperature reading is inconsistent with expected values or other sensors. Possible causes include a faulty coolant temperature sensor, wiring/connector faults, thermostat or cooling system issues, or a control module problem.
🟡 Repair difficulty: Medium
⏱️ Diagnostic time: 1.0-3.0 hours

Similar codes

P0115 P0116 P0117 P0118 P0125 P0128
Your experience will help others
+100 karma for a short comment :)
Keep it short and practical. Up to 500 characters.
Send to email
Code

P1115

CADILLAC P — Powertrain

Engine Coolant Temperature (ECT) Sensor Circuit Intermittent High Voltage

Brand: CADILLAC
Type: P — Powertrain
AI status
Completed
ready
Completed 100%
Page language: EN

Causes

  • Faulty engine coolant temperature (ECT) sensor
  • Open/short or intermittent wiring between sensor and ECU
  • Poor connector connection or corrosion at sensor or ECU
  • Stuck or faulty thermostat causing abnormal coolant temperature behavior
  • Air pocket or low coolant level causing incorrect readings
  • Incorrect sensor installed (wrong type or resistance curve)

Symptoms

  • Illuminated MIL / Check Engine Light
  • Difficult cold starts, extended cranking or poor idle until warm
  • Erratic engine temperature gauge or incorrect dash temperature readings
  • Reduced fuel economy or rich/lean running from incorrect fueling
  • Cooling fan not operating properly or running continuously
  • Possible overheating or poor heater performance

What to check

  • Retrieve freeze frame and live data for ECT, ambient air temp, intake temp and coolant temp during cold start and warm‑up
  • Check for additional related DTCs (P0115, P0116, P0117, P0118, thermostat codes)
  • Visually inspect ECT sensor connector and wiring for corrosion, breaks or damage
  • Measure ECT sensor resistance vs known temperature chart or manufacturer specs
  • Backprobe sensor signal and measure voltage reference and ground with ignition on
  • Verify coolant level and check for air in cooling system; pressurize and inspect for leaks

Signal parameters

  • Sensor type: typically a negative temperature coefficient (NTC) thermistor; resistance decreases as temp rises
  • Typical signal voltage range: 0.0–5.0 V (varies by model and sensor); at cold 2.5–4.5 V, at warm 0.1–1.5 V (manufacturer-specific)
  • Reference supply: usually stable 5 V reference from ECU
  • Expected behavior: smooth monotonic change with temperature and consistent with ambient/engine conditions during warm‑up

Diagnostic algorithm

  1. Verify: Read code, note freeze frame, and check for related codes. Clear code and attempt to reproduce.
  2. Observe live data: With a scan tool monitor ECT, ambient air temp and intake air temp during cold start and warm up. Look for implausible jumps, flatlines or values inconsistent with ambient.
  3. Visual inspection: Check sensor connector for corrosion, bent pins, water intrusion, and secure mounting. Inspect wiring to ECU for damage.
  4. Electrical tests: With ignition on, backprobe: verify ECU 5 V reference present, good ground, and that sensor signal voltage moves with temperature. Check for shorts to power/ground.
  5. Resistance check: Remove sensor and measure resistance at known coolant temperatures (compare to BMW spec or typical NTC curve). Replace if out of spec.
  6. Functional check in‑vehicle: If safe, warm engine and observe ECT change. If ECT reads incorrectly but sensor bench test is good, suspect wiring or ECU.
  7. Cooling system check: Verify coolant level, bleed air from system, and confirm thermostat opens at correct temp — a stuck thermostat can create implausible sensor behavior.
  8. Repair: Replace sensor or repair wiring/connectors as required. If wiring and sensor are good consider ECU/software update or module fault diagnosis.
  9. Confirm: After repair, clear codes and road test to verify correct temperature behavior and that P1115 does not return.

Likely causes

  • Damaged sensor or internal sensor drift
  • Damaged harness (chafing, pinched, water intrusion) between sensor and ECU
  • Loose or corroded sensor connector
  • Thermostat stuck open/closed affecting temperature ramp
  • Low coolant or entrapped air in cooling system

Fault status

⚠️ Status
The engine control module detected an implausible engine coolant temperature signal. The coolant temperature reading is inconsistent with expected values or other sensors. Possible causes include a faulty coolant temperature sensor, wiring/connector faults, thermostat or cooling system issues, or a control module problem.
🟡 Repair difficulty: Medium
⏱️ Diagnostic time: 1.0-3.0 hours

Similar codes

P0115 P0116 P0117 P0118 P0125 P0128
206

Browse 206 CADILLAC manuals: repair procedures, diagnostics, wiring diagrams, component locations, service data and Labor Times by year, model and trim.

CADILLAC

Your experience will help others
+100 karma for a short comment :)
Keep it short and practical. Up to 500 characters.
Send to email
Code

P1115

CHEVROLET P — Powertrain

Engine Coolant Temperature (ECT) Sensor Circuit Intermittent High Voltage

Brand: CHEVROLET
Type: P — Powertrain
AI status
Completed
ready
Completed 100%
Page language: EN

Causes

  • Faulty engine coolant temperature (ECT) sensor
  • Open/short or intermittent wiring between sensor and ECU
  • Poor connector connection or corrosion at sensor or ECU
  • Stuck or faulty thermostat causing abnormal coolant temperature behavior
  • Air pocket or low coolant level causing incorrect readings
  • Incorrect sensor installed (wrong type or resistance curve)

Symptoms

  • Illuminated MIL / Check Engine Light
  • Difficult cold starts, extended cranking or poor idle until warm
  • Erratic engine temperature gauge or incorrect dash temperature readings
  • Reduced fuel economy or rich/lean running from incorrect fueling
  • Cooling fan not operating properly or running continuously
  • Possible overheating or poor heater performance

What to check

  • Retrieve freeze frame and live data for ECT, ambient air temp, intake temp and coolant temp during cold start and warm‑up
  • Check for additional related DTCs (P0115, P0116, P0117, P0118, thermostat codes)
  • Visually inspect ECT sensor connector and wiring for corrosion, breaks or damage
  • Measure ECT sensor resistance vs known temperature chart or manufacturer specs
  • Backprobe sensor signal and measure voltage reference and ground with ignition on
  • Verify coolant level and check for air in cooling system; pressurize and inspect for leaks

Signal parameters

  • Sensor type: typically a negative temperature coefficient (NTC) thermistor; resistance decreases as temp rises
  • Typical signal voltage range: 0.0–5.0 V (varies by model and sensor); at cold 2.5–4.5 V, at warm 0.1–1.5 V (manufacturer-specific)
  • Reference supply: usually stable 5 V reference from ECU
  • Expected behavior: smooth monotonic change with temperature and consistent with ambient/engine conditions during warm‑up

Diagnostic algorithm

  1. Verify: Read code, note freeze frame, and check for related codes. Clear code and attempt to reproduce.
  2. Observe live data: With a scan tool monitor ECT, ambient air temp and intake air temp during cold start and warm up. Look for implausible jumps, flatlines or values inconsistent with ambient.
  3. Visual inspection: Check sensor connector for corrosion, bent pins, water intrusion, and secure mounting. Inspect wiring to ECU for damage.
  4. Electrical tests: With ignition on, backprobe: verify ECU 5 V reference present, good ground, and that sensor signal voltage moves with temperature. Check for shorts to power/ground.
  5. Resistance check: Remove sensor and measure resistance at known coolant temperatures (compare to BMW spec or typical NTC curve). Replace if out of spec.
  6. Functional check in‑vehicle: If safe, warm engine and observe ECT change. If ECT reads incorrectly but sensor bench test is good, suspect wiring or ECU.
  7. Cooling system check: Verify coolant level, bleed air from system, and confirm thermostat opens at correct temp — a stuck thermostat can create implausible sensor behavior.
  8. Repair: Replace sensor or repair wiring/connectors as required. If wiring and sensor are good consider ECU/software update or module fault diagnosis.
  9. Confirm: After repair, clear codes and road test to verify correct temperature behavior and that P1115 does not return.

Likely causes

  • Damaged sensor or internal sensor drift
  • Damaged harness (chafing, pinched, water intrusion) between sensor and ECU
  • Loose or corroded sensor connector
  • Thermostat stuck open/closed affecting temperature ramp
  • Low coolant or entrapped air in cooling system

Fault status

⚠️ Status
The engine control module detected an implausible engine coolant temperature signal. The coolant temperature reading is inconsistent with expected values or other sensors. Possible causes include a faulty coolant temperature sensor, wiring/connector faults, thermostat or cooling system issues, or a control module problem.
🟡 Repair difficulty: Medium
⏱️ Diagnostic time: 1.0-3.0 hours

Similar codes

P0115 P0116 P0117 P0118 P0125 P0128
456

Browse 456 CHEVROLET manuals: repair procedures, diagnostics, wiring diagrams, component locations, service data and Labor Times by year, model and trim.

CHEVROLET

Your experience will help others
+100 karma for a short comment :)
Keep it short and practical. Up to 500 characters.
Send to email
Code

P1115

CHRYSLER P — Powertrain

Engine Coolant Temperature (ECT) Sensor Circuit Intermittent High Voltage

Brand: CHRYSLER
Type: P — Powertrain
AI status
Completed
ready
Completed 100%
Page language: EN

Causes

  • Faulty engine coolant temperature (ECT) sensor
  • Open/short or intermittent wiring between sensor and ECU
  • Poor connector connection or corrosion at sensor or ECU
  • Stuck or faulty thermostat causing abnormal coolant temperature behavior
  • Air pocket or low coolant level causing incorrect readings
  • Incorrect sensor installed (wrong type or resistance curve)

Symptoms

  • Illuminated MIL / Check Engine Light
  • Difficult cold starts, extended cranking or poor idle until warm
  • Erratic engine temperature gauge or incorrect dash temperature readings
  • Reduced fuel economy or rich/lean running from incorrect fueling
  • Cooling fan not operating properly or running continuously
  • Possible overheating or poor heater performance

What to check

  • Retrieve freeze frame and live data for ECT, ambient air temp, intake temp and coolant temp during cold start and warm‑up
  • Check for additional related DTCs (P0115, P0116, P0117, P0118, thermostat codes)
  • Visually inspect ECT sensor connector and wiring for corrosion, breaks or damage
  • Measure ECT sensor resistance vs known temperature chart or manufacturer specs
  • Backprobe sensor signal and measure voltage reference and ground with ignition on
  • Verify coolant level and check for air in cooling system; pressurize and inspect for leaks

Signal parameters

  • Sensor type: typically a negative temperature coefficient (NTC) thermistor; resistance decreases as temp rises
  • Typical signal voltage range: 0.0–5.0 V (varies by model and sensor); at cold 2.5–4.5 V, at warm 0.1–1.5 V (manufacturer-specific)
  • Reference supply: usually stable 5 V reference from ECU
  • Expected behavior: smooth monotonic change with temperature and consistent with ambient/engine conditions during warm‑up

Diagnostic algorithm

  1. Verify: Read code, note freeze frame, and check for related codes. Clear code and attempt to reproduce.
  2. Observe live data: With a scan tool monitor ECT, ambient air temp and intake air temp during cold start and warm up. Look for implausible jumps, flatlines or values inconsistent with ambient.
  3. Visual inspection: Check sensor connector for corrosion, bent pins, water intrusion, and secure mounting. Inspect wiring to ECU for damage.
  4. Electrical tests: With ignition on, backprobe: verify ECU 5 V reference present, good ground, and that sensor signal voltage moves with temperature. Check for shorts to power/ground.
  5. Resistance check: Remove sensor and measure resistance at known coolant temperatures (compare to BMW spec or typical NTC curve). Replace if out of spec.
  6. Functional check in‑vehicle: If safe, warm engine and observe ECT change. If ECT reads incorrectly but sensor bench test is good, suspect wiring or ECU.
  7. Cooling system check: Verify coolant level, bleed air from system, and confirm thermostat opens at correct temp — a stuck thermostat can create implausible sensor behavior.
  8. Repair: Replace sensor or repair wiring/connectors as required. If wiring and sensor are good consider ECU/software update or module fault diagnosis.
  9. Confirm: After repair, clear codes and road test to verify correct temperature behavior and that P1115 does not return.

Likely causes

  • Damaged sensor or internal sensor drift
  • Damaged harness (chafing, pinched, water intrusion) between sensor and ECU
  • Loose or corroded sensor connector
  • Thermostat stuck open/closed affecting temperature ramp
  • Low coolant or entrapped air in cooling system

Fault status

⚠️ Status
The engine control module detected an implausible engine coolant temperature signal. The coolant temperature reading is inconsistent with expected values or other sensors. Possible causes include a faulty coolant temperature sensor, wiring/connector faults, thermostat or cooling system issues, or a control module problem.
🟡 Repair difficulty: Medium
⏱️ Diagnostic time: 1.0-3.0 hours

Similar codes

P0115 P0116 P0117 P0118 P0125 P0128
193

Browse 193 CHRYSLER manuals: repair procedures, diagnostics, wiring diagrams, component locations, service data and Labor Times by year, model and trim.

CHRYSLER

Your experience will help others
+100 karma for a short comment :)
Keep it short and practical. Up to 500 characters.
Send to email
Code

P1115

CITROEN P — Powertrain

Upstream oxygen sensor auto-adaptive

Brand: CITROEN
Type: P — Powertrain
AI status
Completed
ready
Completed 100%
Page language: EN

Causes

  • Faulty engine coolant temperature (ECT) sensor
  • Open/short or intermittent wiring between sensor and ECU
  • Poor connector connection or corrosion at sensor or ECU
  • Stuck or faulty thermostat causing abnormal coolant temperature behavior
  • Air pocket or low coolant level causing incorrect readings
  • Incorrect sensor installed (wrong type or resistance curve)

Symptoms

  • Illuminated MIL / Check Engine Light
  • Difficult cold starts, extended cranking or poor idle until warm
  • Erratic engine temperature gauge or incorrect dash temperature readings
  • Reduced fuel economy or rich/lean running from incorrect fueling
  • Cooling fan not operating properly or running continuously
  • Possible overheating or poor heater performance

What to check

  • Retrieve freeze frame and live data for ECT, ambient air temp, intake temp and coolant temp during cold start and warm‑up
  • Check for additional related DTCs (P0115, P0116, P0117, P0118, thermostat codes)
  • Visually inspect ECT sensor connector and wiring for corrosion, breaks or damage
  • Measure ECT sensor resistance vs known temperature chart or manufacturer specs
  • Backprobe sensor signal and measure voltage reference and ground with ignition on
  • Verify coolant level and check for air in cooling system; pressurize and inspect for leaks

Signal parameters

  • Sensor type: typically a negative temperature coefficient (NTC) thermistor; resistance decreases as temp rises
  • Typical signal voltage range: 0.0–5.0 V (varies by model and sensor); at cold 2.5–4.5 V, at warm 0.1–1.5 V (manufacturer-specific)
  • Reference supply: usually stable 5 V reference from ECU
  • Expected behavior: smooth monotonic change with temperature and consistent with ambient/engine conditions during warm‑up

Diagnostic algorithm

  1. Verify: Read code, note freeze frame, and check for related codes. Clear code and attempt to reproduce.
  2. Observe live data: With a scan tool monitor ECT, ambient air temp and intake air temp during cold start and warm up. Look for implausible jumps, flatlines or values inconsistent with ambient.
  3. Visual inspection: Check sensor connector for corrosion, bent pins, water intrusion, and secure mounting. Inspect wiring to ECU for damage.
  4. Electrical tests: With ignition on, backprobe: verify ECU 5 V reference present, good ground, and that sensor signal voltage moves with temperature. Check for shorts to power/ground.
  5. Resistance check: Remove sensor and measure resistance at known coolant temperatures (compare to BMW spec or typical NTC curve). Replace if out of spec.
  6. Functional check in‑vehicle: If safe, warm engine and observe ECT change. If ECT reads incorrectly but sensor bench test is good, suspect wiring or ECU.
  7. Cooling system check: Verify coolant level, bleed air from system, and confirm thermostat opens at correct temp — a stuck thermostat can create implausible sensor behavior.
  8. Repair: Replace sensor or repair wiring/connectors as required. If wiring and sensor are good consider ECU/software update or module fault diagnosis.
  9. Confirm: After repair, clear codes and road test to verify correct temperature behavior and that P1115 does not return.

Likely causes

  • Damaged sensor or internal sensor drift
  • Damaged harness (chafing, pinched, water intrusion) between sensor and ECU
  • Loose or corroded sensor connector
  • Thermostat stuck open/closed affecting temperature ramp
  • Low coolant or entrapped air in cooling system

Fault status

⚠️ Status
The engine control module detected an implausible engine coolant temperature signal. The coolant temperature reading is inconsistent with expected values or other sensors. Possible causes include a faulty coolant temperature sensor, wiring/connector faults, thermostat or cooling system issues, or a control module problem.
🟡 Repair difficulty: Medium
⏱️ Diagnostic time: 1.0-3.0 hours

Similar codes

P0115 P0116 P0117 P0118 P0125 P0128
Your experience will help others
+100 karma for a short comment :)
Keep it short and practical. Up to 500 characters.
Send to email
Code

P1115

DAEWOO P — Powertrain

COOLANT TEMP SENSOR SIGNAL

Brand: DAEWOO
Type: P — Powertrain
AI status
Completed
ready
Completed 100%
Page language: EN

Causes

  • Faulty engine coolant temperature (ECT) sensor
  • Open/short or intermittent wiring between sensor and ECU
  • Poor connector connection or corrosion at sensor or ECU
  • Stuck or faulty thermostat causing abnormal coolant temperature behavior
  • Air pocket or low coolant level causing incorrect readings
  • Incorrect sensor installed (wrong type or resistance curve)

Symptoms

  • Illuminated MIL / Check Engine Light
  • Difficult cold starts, extended cranking or poor idle until warm
  • Erratic engine temperature gauge or incorrect dash temperature readings
  • Reduced fuel economy or rich/lean running from incorrect fueling
  • Cooling fan not operating properly or running continuously
  • Possible overheating or poor heater performance

What to check

  • Retrieve freeze frame and live data for ECT, ambient air temp, intake temp and coolant temp during cold start and warm‑up
  • Check for additional related DTCs (P0115, P0116, P0117, P0118, thermostat codes)
  • Visually inspect ECT sensor connector and wiring for corrosion, breaks or damage
  • Measure ECT sensor resistance vs known temperature chart or manufacturer specs
  • Backprobe sensor signal and measure voltage reference and ground with ignition on
  • Verify coolant level and check for air in cooling system; pressurize and inspect for leaks

Signal parameters

  • Sensor type: typically a negative temperature coefficient (NTC) thermistor; resistance decreases as temp rises
  • Typical signal voltage range: 0.0–5.0 V (varies by model and sensor); at cold 2.5–4.5 V, at warm 0.1–1.5 V (manufacturer-specific)
  • Reference supply: usually stable 5 V reference from ECU
  • Expected behavior: smooth monotonic change with temperature and consistent with ambient/engine conditions during warm‑up

Diagnostic algorithm

  1. Verify: Read code, note freeze frame, and check for related codes. Clear code and attempt to reproduce.
  2. Observe live data: With a scan tool monitor ECT, ambient air temp and intake air temp during cold start and warm up. Look for implausible jumps, flatlines or values inconsistent with ambient.
  3. Visual inspection: Check sensor connector for corrosion, bent pins, water intrusion, and secure mounting. Inspect wiring to ECU for damage.
  4. Electrical tests: With ignition on, backprobe: verify ECU 5 V reference present, good ground, and that sensor signal voltage moves with temperature. Check for shorts to power/ground.
  5. Resistance check: Remove sensor and measure resistance at known coolant temperatures (compare to BMW spec or typical NTC curve). Replace if out of spec.
  6. Functional check in‑vehicle: If safe, warm engine and observe ECT change. If ECT reads incorrectly but sensor bench test is good, suspect wiring or ECU.
  7. Cooling system check: Verify coolant level, bleed air from system, and confirm thermostat opens at correct temp — a stuck thermostat can create implausible sensor behavior.
  8. Repair: Replace sensor or repair wiring/connectors as required. If wiring and sensor are good consider ECU/software update or module fault diagnosis.
  9. Confirm: After repair, clear codes and road test to verify correct temperature behavior and that P1115 does not return.

Likely causes

  • Damaged sensor or internal sensor drift
  • Damaged harness (chafing, pinched, water intrusion) between sensor and ECU
  • Loose or corroded sensor connector
  • Thermostat stuck open/closed affecting temperature ramp
  • Low coolant or entrapped air in cooling system

Fault status

⚠️ Status
The engine control module detected an implausible engine coolant temperature signal. The coolant temperature reading is inconsistent with expected values or other sensors. Possible causes include a faulty coolant temperature sensor, wiring/connector faults, thermostat or cooling system issues, or a control module problem.
🟡 Repair difficulty: Medium
⏱️ Diagnostic time: 1.0-3.0 hours

Similar codes

P0115 P0116 P0117 P0118 P0125 P0128
Repair manuals

Manual library for DAEWOO

75

Browse 75 DAEWOO manuals: repair procedures, diagnostics, wiring diagrams, component locations, service data and Labor Times by year, model and trim.

DAEWOO

Your experience will help others
+100 karma for a short comment :)
Keep it short and practical. Up to 500 characters.
Send to email
Code

P1115

DS P — Powertrain

Upstream oxygen sensor auto-adaptive

Brand: DS
Type: P — Powertrain
AI status
Completed
ready
Completed 100%
Page language: EN

Causes

  • Faulty engine coolant temperature (ECT) sensor
  • Open/short or intermittent wiring between sensor and ECU
  • Poor connector connection or corrosion at sensor or ECU
  • Stuck or faulty thermostat causing abnormal coolant temperature behavior
  • Air pocket or low coolant level causing incorrect readings
  • Incorrect sensor installed (wrong type or resistance curve)

Symptoms

  • Illuminated MIL / Check Engine Light
  • Difficult cold starts, extended cranking or poor idle until warm
  • Erratic engine temperature gauge or incorrect dash temperature readings
  • Reduced fuel economy or rich/lean running from incorrect fueling
  • Cooling fan not operating properly or running continuously
  • Possible overheating or poor heater performance

What to check

  • Retrieve freeze frame and live data for ECT, ambient air temp, intake temp and coolant temp during cold start and warm‑up
  • Check for additional related DTCs (P0115, P0116, P0117, P0118, thermostat codes)
  • Visually inspect ECT sensor connector and wiring for corrosion, breaks or damage
  • Measure ECT sensor resistance vs known temperature chart or manufacturer specs
  • Backprobe sensor signal and measure voltage reference and ground with ignition on
  • Verify coolant level and check for air in cooling system; pressurize and inspect for leaks

Signal parameters

  • Sensor type: typically a negative temperature coefficient (NTC) thermistor; resistance decreases as temp rises
  • Typical signal voltage range: 0.0–5.0 V (varies by model and sensor); at cold 2.5–4.5 V, at warm 0.1–1.5 V (manufacturer-specific)
  • Reference supply: usually stable 5 V reference from ECU
  • Expected behavior: smooth monotonic change with temperature and consistent with ambient/engine conditions during warm‑up

Diagnostic algorithm

  1. Verify: Read code, note freeze frame, and check for related codes. Clear code and attempt to reproduce.
  2. Observe live data: With a scan tool monitor ECT, ambient air temp and intake air temp during cold start and warm up. Look for implausible jumps, flatlines or values inconsistent with ambient.
  3. Visual inspection: Check sensor connector for corrosion, bent pins, water intrusion, and secure mounting. Inspect wiring to ECU for damage.
  4. Electrical tests: With ignition on, backprobe: verify ECU 5 V reference present, good ground, and that sensor signal voltage moves with temperature. Check for shorts to power/ground.
  5. Resistance check: Remove sensor and measure resistance at known coolant temperatures (compare to BMW spec or typical NTC curve). Replace if out of spec.
  6. Functional check in‑vehicle: If safe, warm engine and observe ECT change. If ECT reads incorrectly but sensor bench test is good, suspect wiring or ECU.
  7. Cooling system check: Verify coolant level, bleed air from system, and confirm thermostat opens at correct temp — a stuck thermostat can create implausible sensor behavior.
  8. Repair: Replace sensor or repair wiring/connectors as required. If wiring and sensor are good consider ECU/software update or module fault diagnosis.
  9. Confirm: After repair, clear codes and road test to verify correct temperature behavior and that P1115 does not return.

Likely causes

  • Damaged sensor or internal sensor drift
  • Damaged harness (chafing, pinched, water intrusion) between sensor and ECU
  • Loose or corroded sensor connector
  • Thermostat stuck open/closed affecting temperature ramp
  • Low coolant or entrapped air in cooling system

Fault status

⚠️ Status
The engine control module detected an implausible engine coolant temperature signal. The coolant temperature reading is inconsistent with expected values or other sensors. Possible causes include a faulty coolant temperature sensor, wiring/connector faults, thermostat or cooling system issues, or a control module problem.
🟡 Repair difficulty: Medium
⏱️ Diagnostic time: 1.0-3.0 hours

Similar codes

P0115 P0116 P0117 P0118 P0125 P0128
Your experience will help others
+100 karma for a short comment :)
Keep it short and practical. Up to 500 characters.
Send to email
Code

P1115

FORD P — Powertrain

Engine Coolant Temperature (ECT) Sensor Circuit Intermittent High Voltage IAT - B Circuit High Input

Brand: FORD
Type: P — Powertrain
AI status
Completed
ready
Completed 100%
Page language: EN

Causes

  • Faulty engine coolant temperature (ECT) sensor
  • Open/short or intermittent wiring between sensor and ECU
  • Poor connector connection or corrosion at sensor or ECU
  • Stuck or faulty thermostat causing abnormal coolant temperature behavior
  • Air pocket or low coolant level causing incorrect readings
  • Incorrect sensor installed (wrong type or resistance curve)

Symptoms

  • Illuminated MIL / Check Engine Light
  • Difficult cold starts, extended cranking or poor idle until warm
  • Erratic engine temperature gauge or incorrect dash temperature readings
  • Reduced fuel economy or rich/lean running from incorrect fueling
  • Cooling fan not operating properly or running continuously
  • Possible overheating or poor heater performance

What to check

  • Retrieve freeze frame and live data for ECT, ambient air temp, intake temp and coolant temp during cold start and warm‑up
  • Check for additional related DTCs (P0115, P0116, P0117, P0118, thermostat codes)
  • Visually inspect ECT sensor connector and wiring for corrosion, breaks or damage
  • Measure ECT sensor resistance vs known temperature chart or manufacturer specs
  • Backprobe sensor signal and measure voltage reference and ground with ignition on
  • Verify coolant level and check for air in cooling system; pressurize and inspect for leaks

Signal parameters

  • Sensor type: typically a negative temperature coefficient (NTC) thermistor; resistance decreases as temp rises
  • Typical signal voltage range: 0.0–5.0 V (varies by model and sensor); at cold 2.5–4.5 V, at warm 0.1–1.5 V (manufacturer-specific)
  • Reference supply: usually stable 5 V reference from ECU
  • Expected behavior: smooth monotonic change with temperature and consistent with ambient/engine conditions during warm‑up

Diagnostic algorithm

  1. Verify: Read code, note freeze frame, and check for related codes. Clear code and attempt to reproduce.
  2. Observe live data: With a scan tool monitor ECT, ambient air temp and intake air temp during cold start and warm up. Look for implausible jumps, flatlines or values inconsistent with ambient.
  3. Visual inspection: Check sensor connector for corrosion, bent pins, water intrusion, and secure mounting. Inspect wiring to ECU for damage.
  4. Electrical tests: With ignition on, backprobe: verify ECU 5 V reference present, good ground, and that sensor signal voltage moves with temperature. Check for shorts to power/ground.
  5. Resistance check: Remove sensor and measure resistance at known coolant temperatures (compare to BMW spec or typical NTC curve). Replace if out of spec.
  6. Functional check in‑vehicle: If safe, warm engine and observe ECT change. If ECT reads incorrectly but sensor bench test is good, suspect wiring or ECU.
  7. Cooling system check: Verify coolant level, bleed air from system, and confirm thermostat opens at correct temp — a stuck thermostat can create implausible sensor behavior.
  8. Repair: Replace sensor or repair wiring/connectors as required. If wiring and sensor are good consider ECU/software update or module fault diagnosis.
  9. Confirm: After repair, clear codes and road test to verify correct temperature behavior and that P1115 does not return.

Likely causes

  • Damaged sensor or internal sensor drift
  • Damaged harness (chafing, pinched, water intrusion) between sensor and ECU
  • Loose or corroded sensor connector
  • Thermostat stuck open/closed affecting temperature ramp
  • Low coolant or entrapped air in cooling system

Fault status

⚠️ Status
The engine control module detected an implausible engine coolant temperature signal. The coolant temperature reading is inconsistent with expected values or other sensors. Possible causes include a faulty coolant temperature sensor, wiring/connector faults, thermostat or cooling system issues, or a control module problem.
🟡 Repair difficulty: Medium
⏱️ Diagnostic time: 1.0-3.0 hours

Similar codes

P0115 P0116 P0117 P0118 P0125 P0128
Your experience will help others
+100 karma for a short comment :)
Keep it short and practical. Up to 500 characters.
Send to email
Code

P1115

GM P — Powertrain

Engine Coolant Temperature (ECT) Sensor Circuit Intermittent High Voltage

Brand: GM
Type: P — Powertrain
AI status
Completed
ready
Completed 100%
Page language: EN

Causes

  • Faulty engine coolant temperature (ECT) sensor
  • Open/short or intermittent wiring between sensor and ECU
  • Poor connector connection or corrosion at sensor or ECU
  • Stuck or faulty thermostat causing abnormal coolant temperature behavior
  • Air pocket or low coolant level causing incorrect readings
  • Incorrect sensor installed (wrong type or resistance curve)

Symptoms

  • Illuminated MIL / Check Engine Light
  • Difficult cold starts, extended cranking or poor idle until warm
  • Erratic engine temperature gauge or incorrect dash temperature readings
  • Reduced fuel economy or rich/lean running from incorrect fueling
  • Cooling fan not operating properly or running continuously
  • Possible overheating or poor heater performance

What to check

  • Retrieve freeze frame and live data for ECT, ambient air temp, intake temp and coolant temp during cold start and warm‑up
  • Check for additional related DTCs (P0115, P0116, P0117, P0118, thermostat codes)
  • Visually inspect ECT sensor connector and wiring for corrosion, breaks or damage
  • Measure ECT sensor resistance vs known temperature chart or manufacturer specs
  • Backprobe sensor signal and measure voltage reference and ground with ignition on
  • Verify coolant level and check for air in cooling system; pressurize and inspect for leaks

Signal parameters

  • Sensor type: typically a negative temperature coefficient (NTC) thermistor; resistance decreases as temp rises
  • Typical signal voltage range: 0.0–5.0 V (varies by model and sensor); at cold 2.5–4.5 V, at warm 0.1–1.5 V (manufacturer-specific)
  • Reference supply: usually stable 5 V reference from ECU
  • Expected behavior: smooth monotonic change with temperature and consistent with ambient/engine conditions during warm‑up

Diagnostic algorithm

  1. Verify: Read code, note freeze frame, and check for related codes. Clear code and attempt to reproduce.
  2. Observe live data: With a scan tool monitor ECT, ambient air temp and intake air temp during cold start and warm up. Look for implausible jumps, flatlines or values inconsistent with ambient.
  3. Visual inspection: Check sensor connector for corrosion, bent pins, water intrusion, and secure mounting. Inspect wiring to ECU for damage.
  4. Electrical tests: With ignition on, backprobe: verify ECU 5 V reference present, good ground, and that sensor signal voltage moves with temperature. Check for shorts to power/ground.
  5. Resistance check: Remove sensor and measure resistance at known coolant temperatures (compare to BMW spec or typical NTC curve). Replace if out of spec.
  6. Functional check in‑vehicle: If safe, warm engine and observe ECT change. If ECT reads incorrectly but sensor bench test is good, suspect wiring or ECU.
  7. Cooling system check: Verify coolant level, bleed air from system, and confirm thermostat opens at correct temp — a stuck thermostat can create implausible sensor behavior.
  8. Repair: Replace sensor or repair wiring/connectors as required. If wiring and sensor are good consider ECU/software update or module fault diagnosis.
  9. Confirm: After repair, clear codes and road test to verify correct temperature behavior and that P1115 does not return.

Likely causes

  • Damaged sensor or internal sensor drift
  • Damaged harness (chafing, pinched, water intrusion) between sensor and ECU
  • Loose or corroded sensor connector
  • Thermostat stuck open/closed affecting temperature ramp
  • Low coolant or entrapped air in cooling system

Fault status

⚠️ Status
The engine control module detected an implausible engine coolant temperature signal. The coolant temperature reading is inconsistent with expected values or other sensors. Possible causes include a faulty coolant temperature sensor, wiring/connector faults, thermostat or cooling system issues, or a control module problem.
🟡 Repair difficulty: Medium
⏱️ Diagnostic time: 1.0-3.0 hours

Similar codes

P0115 P0116 P0117 P0118 P0125 P0128
Your experience will help others
+100 karma for a short comment :)
Keep it short and practical. Up to 500 characters.
Send to email
Code

P1115

GMC P — Powertrain

Engine Coolant Temperature (ECT) Sensor Circuit Intermittent High Voltage

Brand: GMC
Type: P — Powertrain
AI status
Completed
ready
Completed 100%
Page language: EN

Causes

  • Faulty engine coolant temperature (ECT) sensor
  • Open/short or intermittent wiring between sensor and ECU
  • Poor connector connection or corrosion at sensor or ECU
  • Stuck or faulty thermostat causing abnormal coolant temperature behavior
  • Air pocket or low coolant level causing incorrect readings
  • Incorrect sensor installed (wrong type or resistance curve)

Symptoms

  • Illuminated MIL / Check Engine Light
  • Difficult cold starts, extended cranking or poor idle until warm
  • Erratic engine temperature gauge or incorrect dash temperature readings
  • Reduced fuel economy or rich/lean running from incorrect fueling
  • Cooling fan not operating properly or running continuously
  • Possible overheating or poor heater performance

What to check

  • Retrieve freeze frame and live data for ECT, ambient air temp, intake temp and coolant temp during cold start and warm‑up
  • Check for additional related DTCs (P0115, P0116, P0117, P0118, thermostat codes)
  • Visually inspect ECT sensor connector and wiring for corrosion, breaks or damage
  • Measure ECT sensor resistance vs known temperature chart or manufacturer specs
  • Backprobe sensor signal and measure voltage reference and ground with ignition on
  • Verify coolant level and check for air in cooling system; pressurize and inspect for leaks

Signal parameters

  • Sensor type: typically a negative temperature coefficient (NTC) thermistor; resistance decreases as temp rises
  • Typical signal voltage range: 0.0–5.0 V (varies by model and sensor); at cold 2.5–4.5 V, at warm 0.1–1.5 V (manufacturer-specific)
  • Reference supply: usually stable 5 V reference from ECU
  • Expected behavior: smooth monotonic change with temperature and consistent with ambient/engine conditions during warm‑up

Diagnostic algorithm

  1. Verify: Read code, note freeze frame, and check for related codes. Clear code and attempt to reproduce.
  2. Observe live data: With a scan tool monitor ECT, ambient air temp and intake air temp during cold start and warm up. Look for implausible jumps, flatlines or values inconsistent with ambient.
  3. Visual inspection: Check sensor connector for corrosion, bent pins, water intrusion, and secure mounting. Inspect wiring to ECU for damage.
  4. Electrical tests: With ignition on, backprobe: verify ECU 5 V reference present, good ground, and that sensor signal voltage moves with temperature. Check for shorts to power/ground.
  5. Resistance check: Remove sensor and measure resistance at known coolant temperatures (compare to BMW spec or typical NTC curve). Replace if out of spec.
  6. Functional check in‑vehicle: If safe, warm engine and observe ECT change. If ECT reads incorrectly but sensor bench test is good, suspect wiring or ECU.
  7. Cooling system check: Verify coolant level, bleed air from system, and confirm thermostat opens at correct temp — a stuck thermostat can create implausible sensor behavior.
  8. Repair: Replace sensor or repair wiring/connectors as required. If wiring and sensor are good consider ECU/software update or module fault diagnosis.
  9. Confirm: After repair, clear codes and road test to verify correct temperature behavior and that P1115 does not return.

Likely causes

  • Damaged sensor or internal sensor drift
  • Damaged harness (chafing, pinched, water intrusion) between sensor and ECU
  • Loose or corroded sensor connector
  • Thermostat stuck open/closed affecting temperature ramp
  • Low coolant or entrapped air in cooling system

Fault status

⚠️ Status
The engine control module detected an implausible engine coolant temperature signal. The coolant temperature reading is inconsistent with expected values or other sensors. Possible causes include a faulty coolant temperature sensor, wiring/connector faults, thermostat or cooling system issues, or a control module problem.
🟡 Repair difficulty: Medium
⏱️ Diagnostic time: 1.0-3.0 hours

Similar codes

P0115 P0116 P0117 P0118 P0125 P0128
Your experience will help others
+100 karma for a short comment :)
Keep it short and practical. Up to 500 characters.
Send to email
Code

P1115

GWM P — Powertrain

- High voltage in the coolant temperature sensor circuit (ECT)

Brand: GWM
Type: P — Powertrain
AI status
Completed
ready
Completed 100%
Page language: EN

Causes

  • Faulty engine coolant temperature (ECT) sensor
  • Open/short or intermittent wiring between sensor and ECU
  • Poor connector connection or corrosion at sensor or ECU
  • Stuck or faulty thermostat causing abnormal coolant temperature behavior
  • Air pocket or low coolant level causing incorrect readings
  • Incorrect sensor installed (wrong type or resistance curve)

Symptoms

  • Illuminated MIL / Check Engine Light
  • Difficult cold starts, extended cranking or poor idle until warm
  • Erratic engine temperature gauge or incorrect dash temperature readings
  • Reduced fuel economy or rich/lean running from incorrect fueling
  • Cooling fan not operating properly or running continuously
  • Possible overheating or poor heater performance

What to check

  • Retrieve freeze frame and live data for ECT, ambient air temp, intake temp and coolant temp during cold start and warm‑up
  • Check for additional related DTCs (P0115, P0116, P0117, P0118, thermostat codes)
  • Visually inspect ECT sensor connector and wiring for corrosion, breaks or damage
  • Measure ECT sensor resistance vs known temperature chart or manufacturer specs
  • Backprobe sensor signal and measure voltage reference and ground with ignition on
  • Verify coolant level and check for air in cooling system; pressurize and inspect for leaks

Signal parameters

  • Sensor type: typically a negative temperature coefficient (NTC) thermistor; resistance decreases as temp rises
  • Typical signal voltage range: 0.0–5.0 V (varies by model and sensor); at cold 2.5–4.5 V, at warm 0.1–1.5 V (manufacturer-specific)
  • Reference supply: usually stable 5 V reference from ECU
  • Expected behavior: smooth monotonic change with temperature and consistent with ambient/engine conditions during warm‑up

Diagnostic algorithm

  1. Verify: Read code, note freeze frame, and check for related codes. Clear code and attempt to reproduce.
  2. Observe live data: With a scan tool monitor ECT, ambient air temp and intake air temp during cold start and warm up. Look for implausible jumps, flatlines or values inconsistent with ambient.
  3. Visual inspection: Check sensor connector for corrosion, bent pins, water intrusion, and secure mounting. Inspect wiring to ECU for damage.
  4. Electrical tests: With ignition on, backprobe: verify ECU 5 V reference present, good ground, and that sensor signal voltage moves with temperature. Check for shorts to power/ground.
  5. Resistance check: Remove sensor and measure resistance at known coolant temperatures (compare to BMW spec or typical NTC curve). Replace if out of spec.
  6. Functional check in‑vehicle: If safe, warm engine and observe ECT change. If ECT reads incorrectly but sensor bench test is good, suspect wiring or ECU.
  7. Cooling system check: Verify coolant level, bleed air from system, and confirm thermostat opens at correct temp — a stuck thermostat can create implausible sensor behavior.
  8. Repair: Replace sensor or repair wiring/connectors as required. If wiring and sensor are good consider ECU/software update or module fault diagnosis.
  9. Confirm: After repair, clear codes and road test to verify correct temperature behavior and that P1115 does not return.

Likely causes

  • Damaged sensor or internal sensor drift
  • Damaged harness (chafing, pinched, water intrusion) between sensor and ECU
  • Loose or corroded sensor connector
  • Thermostat stuck open/closed affecting temperature ramp
  • Low coolant or entrapped air in cooling system

Fault status

⚠️ Status
The engine control module detected an implausible engine coolant temperature signal. The coolant temperature reading is inconsistent with expected values or other sensors. Possible causes include a faulty coolant temperature sensor, wiring/connector faults, thermostat or cooling system issues, or a control module problem.
🟡 Repair difficulty: Medium
⏱️ Diagnostic time: 1.0-3.0 hours

Similar codes

P0115 P0116 P0117 P0118 P0125 P0128
Your experience will help others
+100 karma for a short comment :)
Keep it short and practical. Up to 500 characters.
Send to email
Code

P1115

HUMMER P — Powertrain

Engine Coolant Temperature (ECT) Sensor Circuit Intermittent High Voltage

Brand: HUMMER
Type: P — Powertrain
AI status
Completed
ready
Completed 100%
Page language: EN

Causes

  • Faulty engine coolant temperature (ECT) sensor
  • Open/short or intermittent wiring between sensor and ECU
  • Poor connector connection or corrosion at sensor or ECU
  • Stuck or faulty thermostat causing abnormal coolant temperature behavior
  • Air pocket or low coolant level causing incorrect readings
  • Incorrect sensor installed (wrong type or resistance curve)

Symptoms

  • Illuminated MIL / Check Engine Light
  • Difficult cold starts, extended cranking or poor idle until warm
  • Erratic engine temperature gauge or incorrect dash temperature readings
  • Reduced fuel economy or rich/lean running from incorrect fueling
  • Cooling fan not operating properly or running continuously
  • Possible overheating or poor heater performance

What to check

  • Retrieve freeze frame and live data for ECT, ambient air temp, intake temp and coolant temp during cold start and warm‑up
  • Check for additional related DTCs (P0115, P0116, P0117, P0118, thermostat codes)
  • Visually inspect ECT sensor connector and wiring for corrosion, breaks or damage
  • Measure ECT sensor resistance vs known temperature chart or manufacturer specs
  • Backprobe sensor signal and measure voltage reference and ground with ignition on
  • Verify coolant level and check for air in cooling system; pressurize and inspect for leaks

Signal parameters

  • Sensor type: typically a negative temperature coefficient (NTC) thermistor; resistance decreases as temp rises
  • Typical signal voltage range: 0.0–5.0 V (varies by model and sensor); at cold 2.5–4.5 V, at warm 0.1–1.5 V (manufacturer-specific)
  • Reference supply: usually stable 5 V reference from ECU
  • Expected behavior: smooth monotonic change with temperature and consistent with ambient/engine conditions during warm‑up

Diagnostic algorithm

  1. Verify: Read code, note freeze frame, and check for related codes. Clear code and attempt to reproduce.
  2. Observe live data: With a scan tool monitor ECT, ambient air temp and intake air temp during cold start and warm up. Look for implausible jumps, flatlines or values inconsistent with ambient.
  3. Visual inspection: Check sensor connector for corrosion, bent pins, water intrusion, and secure mounting. Inspect wiring to ECU for damage.
  4. Electrical tests: With ignition on, backprobe: verify ECU 5 V reference present, good ground, and that sensor signal voltage moves with temperature. Check for shorts to power/ground.
  5. Resistance check: Remove sensor and measure resistance at known coolant temperatures (compare to BMW spec or typical NTC curve). Replace if out of spec.
  6. Functional check in‑vehicle: If safe, warm engine and observe ECT change. If ECT reads incorrectly but sensor bench test is good, suspect wiring or ECU.
  7. Cooling system check: Verify coolant level, bleed air from system, and confirm thermostat opens at correct temp — a stuck thermostat can create implausible sensor behavior.
  8. Repair: Replace sensor or repair wiring/connectors as required. If wiring and sensor are good consider ECU/software update or module fault diagnosis.
  9. Confirm: After repair, clear codes and road test to verify correct temperature behavior and that P1115 does not return.

Likely causes

  • Damaged sensor or internal sensor drift
  • Damaged harness (chafing, pinched, water intrusion) between sensor and ECU
  • Loose or corroded sensor connector
  • Thermostat stuck open/closed affecting temperature ramp
  • Low coolant or entrapped air in cooling system

Fault status

⚠️ Status
The engine control module detected an implausible engine coolant temperature signal. The coolant temperature reading is inconsistent with expected values or other sensors. Possible causes include a faulty coolant temperature sensor, wiring/connector faults, thermostat or cooling system issues, or a control module problem.
🟡 Repair difficulty: Medium
⏱️ Diagnostic time: 1.0-3.0 hours

Similar codes

P0115 P0116 P0117 P0118 P0125 P0128
Repair manuals

Manual library for HUMMER

138

Browse 138 HUMMER manuals: repair procedures, diagnostics, wiring diagrams, component locations, service data and Labor Times by year, model and trim.

HUMMER

Your experience will help others
+100 karma for a short comment :)
Keep it short and practical. Up to 500 characters.
Send to email
Code

P1115

KIA P — Powertrain

H02S12 Heater Circuit Low Voltage

Brand: KIA
Type: P — Powertrain
AI status
Completed
ready
Completed 100%
Page language: EN

Causes

  • Faulty engine coolant temperature (ECT) sensor
  • Open/short or intermittent wiring between sensor and ECU
  • Poor connector connection or corrosion at sensor or ECU
  • Stuck or faulty thermostat causing abnormal coolant temperature behavior
  • Air pocket or low coolant level causing incorrect readings
  • Incorrect sensor installed (wrong type or resistance curve)

Symptoms

  • Illuminated MIL / Check Engine Light
  • Difficult cold starts, extended cranking or poor idle until warm
  • Erratic engine temperature gauge or incorrect dash temperature readings
  • Reduced fuel economy or rich/lean running from incorrect fueling
  • Cooling fan not operating properly or running continuously
  • Possible overheating or poor heater performance

What to check

  • Retrieve freeze frame and live data for ECT, ambient air temp, intake temp and coolant temp during cold start and warm‑up
  • Check for additional related DTCs (P0115, P0116, P0117, P0118, thermostat codes)
  • Visually inspect ECT sensor connector and wiring for corrosion, breaks or damage
  • Measure ECT sensor resistance vs known temperature chart or manufacturer specs
  • Backprobe sensor signal and measure voltage reference and ground with ignition on
  • Verify coolant level and check for air in cooling system; pressurize and inspect for leaks

Signal parameters

  • Sensor type: typically a negative temperature coefficient (NTC) thermistor; resistance decreases as temp rises
  • Typical signal voltage range: 0.0–5.0 V (varies by model and sensor); at cold 2.5–4.5 V, at warm 0.1–1.5 V (manufacturer-specific)
  • Reference supply: usually stable 5 V reference from ECU
  • Expected behavior: smooth monotonic change with temperature and consistent with ambient/engine conditions during warm‑up

Diagnostic algorithm

  1. Verify: Read code, note freeze frame, and check for related codes. Clear code and attempt to reproduce.
  2. Observe live data: With a scan tool monitor ECT, ambient air temp and intake air temp during cold start and warm up. Look for implausible jumps, flatlines or values inconsistent with ambient.
  3. Visual inspection: Check sensor connector for corrosion, bent pins, water intrusion, and secure mounting. Inspect wiring to ECU for damage.
  4. Electrical tests: With ignition on, backprobe: verify ECU 5 V reference present, good ground, and that sensor signal voltage moves with temperature. Check for shorts to power/ground.
  5. Resistance check: Remove sensor and measure resistance at known coolant temperatures (compare to BMW spec or typical NTC curve). Replace if out of spec.
  6. Functional check in‑vehicle: If safe, warm engine and observe ECT change. If ECT reads incorrectly but sensor bench test is good, suspect wiring or ECU.
  7. Cooling system check: Verify coolant level, bleed air from system, and confirm thermostat opens at correct temp — a stuck thermostat can create implausible sensor behavior.
  8. Repair: Replace sensor or repair wiring/connectors as required. If wiring and sensor are good consider ECU/software update or module fault diagnosis.
  9. Confirm: After repair, clear codes and road test to verify correct temperature behavior and that P1115 does not return.

Likely causes

  • Damaged sensor or internal sensor drift
  • Damaged harness (chafing, pinched, water intrusion) between sensor and ECU
  • Loose or corroded sensor connector
  • Thermostat stuck open/closed affecting temperature ramp
  • Low coolant or entrapped air in cooling system

Fault status

⚠️ Status
The engine control module detected an implausible engine coolant temperature signal. The coolant temperature reading is inconsistent with expected values or other sensors. Possible causes include a faulty coolant temperature sensor, wiring/connector faults, thermostat or cooling system issues, or a control module problem.
🟡 Repair difficulty: Medium
⏱️ Diagnostic time: 1.0-3.0 hours

Similar codes

P0115 P0116 P0117 P0118 P0125 P0128
Repair manuals

Manual library for KIA

155

Browse 155 KIA manuals: repair procedures, diagnostics, wiring diagrams, component locations, service data and Labor Times by year, model and trim.

KIA

Your experience will help others
+100 karma for a short comment :)
Keep it short and practical. Up to 500 characters.
Send to email
Code

P1115

LAND ROVER P — Powertrain

Air temperature input 2 - high circuit (super engines / turbocharged

Brand: LAND ROVER
Type: P — Powertrain
AI status
Completed
ready
Completed 100%
Page language: EN

Causes

  • Faulty engine coolant temperature (ECT) sensor
  • Open/short or intermittent wiring between sensor and ECU
  • Poor connector connection or corrosion at sensor or ECU
  • Stuck or faulty thermostat causing abnormal coolant temperature behavior
  • Air pocket or low coolant level causing incorrect readings
  • Incorrect sensor installed (wrong type or resistance curve)

Symptoms

  • Illuminated MIL / Check Engine Light
  • Difficult cold starts, extended cranking or poor idle until warm
  • Erratic engine temperature gauge or incorrect dash temperature readings
  • Reduced fuel economy or rich/lean running from incorrect fueling
  • Cooling fan not operating properly or running continuously
  • Possible overheating or poor heater performance

What to check

  • Retrieve freeze frame and live data for ECT, ambient air temp, intake temp and coolant temp during cold start and warm‑up
  • Check for additional related DTCs (P0115, P0116, P0117, P0118, thermostat codes)
  • Visually inspect ECT sensor connector and wiring for corrosion, breaks or damage
  • Measure ECT sensor resistance vs known temperature chart or manufacturer specs
  • Backprobe sensor signal and measure voltage reference and ground with ignition on
  • Verify coolant level and check for air in cooling system; pressurize and inspect for leaks

Signal parameters

  • Sensor type: typically a negative temperature coefficient (NTC) thermistor; resistance decreases as temp rises
  • Typical signal voltage range: 0.0–5.0 V (varies by model and sensor); at cold 2.5–4.5 V, at warm 0.1–1.5 V (manufacturer-specific)
  • Reference supply: usually stable 5 V reference from ECU
  • Expected behavior: smooth monotonic change with temperature and consistent with ambient/engine conditions during warm‑up

Diagnostic algorithm

  1. Verify: Read code, note freeze frame, and check for related codes. Clear code and attempt to reproduce.
  2. Observe live data: With a scan tool monitor ECT, ambient air temp and intake air temp during cold start and warm up. Look for implausible jumps, flatlines or values inconsistent with ambient.
  3. Visual inspection: Check sensor connector for corrosion, bent pins, water intrusion, and secure mounting. Inspect wiring to ECU for damage.
  4. Electrical tests: With ignition on, backprobe: verify ECU 5 V reference present, good ground, and that sensor signal voltage moves with temperature. Check for shorts to power/ground.
  5. Resistance check: Remove sensor and measure resistance at known coolant temperatures (compare to BMW spec or typical NTC curve). Replace if out of spec.
  6. Functional check in‑vehicle: If safe, warm engine and observe ECT change. If ECT reads incorrectly but sensor bench test is good, suspect wiring or ECU.
  7. Cooling system check: Verify coolant level, bleed air from system, and confirm thermostat opens at correct temp — a stuck thermostat can create implausible sensor behavior.
  8. Repair: Replace sensor or repair wiring/connectors as required. If wiring and sensor are good consider ECU/software update or module fault diagnosis.
  9. Confirm: After repair, clear codes and road test to verify correct temperature behavior and that P1115 does not return.

Likely causes

  • Damaged sensor or internal sensor drift
  • Damaged harness (chafing, pinched, water intrusion) between sensor and ECU
  • Loose or corroded sensor connector
  • Thermostat stuck open/closed affecting temperature ramp
  • Low coolant or entrapped air in cooling system

Fault status

⚠️ Status
The engine control module detected an implausible engine coolant temperature signal. The coolant temperature reading is inconsistent with expected values or other sensors. Possible causes include a faulty coolant temperature sensor, wiring/connector faults, thermostat or cooling system issues, or a control module problem.
🟡 Repair difficulty: Medium
⏱️ Diagnostic time: 1.0-3.0 hours

Similar codes

P0115 P0116 P0117 P0118 P0125 P0128
266

Browse 266 LAND ROVER manuals: repair procedures, diagnostics, wiring diagrams, component locations, service data and Labor Times by year, model and trim.

LAND ROVER

Your experience will help others
+100 karma for a short comment :)
Keep it short and practical. Up to 500 characters.
Send to email
Code

P1115

LINCOLN P — Powertrain

Engine Coolant Temperature (ECT) Sensor Circuit Intermittent High Voltage IAT B Circuit High Input

Brand: LINCOLN
Type: P — Powertrain
AI status
Completed
ready
Completed 100%
Page language: EN

Causes

  • Faulty engine coolant temperature (ECT) sensor
  • Open/short or intermittent wiring between sensor and ECU
  • Poor connector connection or corrosion at sensor or ECU
  • Stuck or faulty thermostat causing abnormal coolant temperature behavior
  • Air pocket or low coolant level causing incorrect readings
  • Incorrect sensor installed (wrong type or resistance curve)

Symptoms

  • Illuminated MIL / Check Engine Light
  • Difficult cold starts, extended cranking or poor idle until warm
  • Erratic engine temperature gauge or incorrect dash temperature readings
  • Reduced fuel economy or rich/lean running from incorrect fueling
  • Cooling fan not operating properly or running continuously
  • Possible overheating or poor heater performance

What to check

  • Retrieve freeze frame and live data for ECT, ambient air temp, intake temp and coolant temp during cold start and warm‑up
  • Check for additional related DTCs (P0115, P0116, P0117, P0118, thermostat codes)
  • Visually inspect ECT sensor connector and wiring for corrosion, breaks or damage
  • Measure ECT sensor resistance vs known temperature chart or manufacturer specs
  • Backprobe sensor signal and measure voltage reference and ground with ignition on
  • Verify coolant level and check for air in cooling system; pressurize and inspect for leaks

Signal parameters

  • Sensor type: typically a negative temperature coefficient (NTC) thermistor; resistance decreases as temp rises
  • Typical signal voltage range: 0.0–5.0 V (varies by model and sensor); at cold 2.5–4.5 V, at warm 0.1–1.5 V (manufacturer-specific)
  • Reference supply: usually stable 5 V reference from ECU
  • Expected behavior: smooth monotonic change with temperature and consistent with ambient/engine conditions during warm‑up

Diagnostic algorithm

  1. Verify: Read code, note freeze frame, and check for related codes. Clear code and attempt to reproduce.
  2. Observe live data: With a scan tool monitor ECT, ambient air temp and intake air temp during cold start and warm up. Look for implausible jumps, flatlines or values inconsistent with ambient.
  3. Visual inspection: Check sensor connector for corrosion, bent pins, water intrusion, and secure mounting. Inspect wiring to ECU for damage.
  4. Electrical tests: With ignition on, backprobe: verify ECU 5 V reference present, good ground, and that sensor signal voltage moves with temperature. Check for shorts to power/ground.
  5. Resistance check: Remove sensor and measure resistance at known coolant temperatures (compare to BMW spec or typical NTC curve). Replace if out of spec.
  6. Functional check in‑vehicle: If safe, warm engine and observe ECT change. If ECT reads incorrectly but sensor bench test is good, suspect wiring or ECU.
  7. Cooling system check: Verify coolant level, bleed air from system, and confirm thermostat opens at correct temp — a stuck thermostat can create implausible sensor behavior.
  8. Repair: Replace sensor or repair wiring/connectors as required. If wiring and sensor are good consider ECU/software update or module fault diagnosis.
  9. Confirm: After repair, clear codes and road test to verify correct temperature behavior and that P1115 does not return.

Likely causes

  • Damaged sensor or internal sensor drift
  • Damaged harness (chafing, pinched, water intrusion) between sensor and ECU
  • Loose or corroded sensor connector
  • Thermostat stuck open/closed affecting temperature ramp
  • Low coolant or entrapped air in cooling system

Fault status

⚠️ Status
The engine control module detected an implausible engine coolant temperature signal. The coolant temperature reading is inconsistent with expected values or other sensors. Possible causes include a faulty coolant temperature sensor, wiring/connector faults, thermostat or cooling system issues, or a control module problem.
🟡 Repair difficulty: Medium
⏱️ Diagnostic time: 1.0-3.0 hours

Similar codes

P0115 P0116 P0117 P0118 P0125 P0128
166

Browse 166 LINCOLN manuals: repair procedures, diagnostics, wiring diagrams, component locations, service data and Labor Times by year, model and trim.

LINCOLN

Your experience will help others
+100 karma for a short comment :)
Keep it short and practical. Up to 500 characters.
Send to email
Code

P1115

MERCURY P — Powertrain

Engine Coolant Temperature (ECT) Sensor Circuit Intermittent High Voltage IAT B Circuit High Input

Brand: MERCURY
Type: P — Powertrain
AI status
Completed
ready
Completed 100%
Page language: EN

Causes

  • Faulty engine coolant temperature (ECT) sensor
  • Open/short or intermittent wiring between sensor and ECU
  • Poor connector connection or corrosion at sensor or ECU
  • Stuck or faulty thermostat causing abnormal coolant temperature behavior
  • Air pocket or low coolant level causing incorrect readings
  • Incorrect sensor installed (wrong type or resistance curve)

Symptoms

  • Illuminated MIL / Check Engine Light
  • Difficult cold starts, extended cranking or poor idle until warm
  • Erratic engine temperature gauge or incorrect dash temperature readings
  • Reduced fuel economy or rich/lean running from incorrect fueling
  • Cooling fan not operating properly or running continuously
  • Possible overheating or poor heater performance

What to check

  • Retrieve freeze frame and live data for ECT, ambient air temp, intake temp and coolant temp during cold start and warm‑up
  • Check for additional related DTCs (P0115, P0116, P0117, P0118, thermostat codes)
  • Visually inspect ECT sensor connector and wiring for corrosion, breaks or damage
  • Measure ECT sensor resistance vs known temperature chart or manufacturer specs
  • Backprobe sensor signal and measure voltage reference and ground with ignition on
  • Verify coolant level and check for air in cooling system; pressurize and inspect for leaks

Signal parameters

  • Sensor type: typically a negative temperature coefficient (NTC) thermistor; resistance decreases as temp rises
  • Typical signal voltage range: 0.0–5.0 V (varies by model and sensor); at cold 2.5–4.5 V, at warm 0.1–1.5 V (manufacturer-specific)
  • Reference supply: usually stable 5 V reference from ECU
  • Expected behavior: smooth monotonic change with temperature and consistent with ambient/engine conditions during warm‑up

Diagnostic algorithm

  1. Verify: Read code, note freeze frame, and check for related codes. Clear code and attempt to reproduce.
  2. Observe live data: With a scan tool monitor ECT, ambient air temp and intake air temp during cold start and warm up. Look for implausible jumps, flatlines or values inconsistent with ambient.
  3. Visual inspection: Check sensor connector for corrosion, bent pins, water intrusion, and secure mounting. Inspect wiring to ECU for damage.
  4. Electrical tests: With ignition on, backprobe: verify ECU 5 V reference present, good ground, and that sensor signal voltage moves with temperature. Check for shorts to power/ground.
  5. Resistance check: Remove sensor and measure resistance at known coolant temperatures (compare to BMW spec or typical NTC curve). Replace if out of spec.
  6. Functional check in‑vehicle: If safe, warm engine and observe ECT change. If ECT reads incorrectly but sensor bench test is good, suspect wiring or ECU.
  7. Cooling system check: Verify coolant level, bleed air from system, and confirm thermostat opens at correct temp — a stuck thermostat can create implausible sensor behavior.
  8. Repair: Replace sensor or repair wiring/connectors as required. If wiring and sensor are good consider ECU/software update or module fault diagnosis.
  9. Confirm: After repair, clear codes and road test to verify correct temperature behavior and that P1115 does not return.

Likely causes

  • Damaged sensor or internal sensor drift
  • Damaged harness (chafing, pinched, water intrusion) between sensor and ECU
  • Loose or corroded sensor connector
  • Thermostat stuck open/closed affecting temperature ramp
  • Low coolant or entrapped air in cooling system

Fault status

⚠️ Status
The engine control module detected an implausible engine coolant temperature signal. The coolant temperature reading is inconsistent with expected values or other sensors. Possible causes include a faulty coolant temperature sensor, wiring/connector faults, thermostat or cooling system issues, or a control module problem.
🟡 Repair difficulty: Medium
⏱️ Diagnostic time: 1.0-3.0 hours

Similar codes

P0115 P0116 P0117 P0118 P0125 P0128
296

Browse 296 MERCURY manuals: repair procedures, diagnostics, wiring diagrams, component locations, service data and Labor Times by year, model and trim.

MERCURY

Your experience will help others
+100 karma for a short comment :)
Keep it short and practical. Up to 500 characters.
Send to email
Code

P1115

OLDSMOBILE P — Powertrain

Engine Coolant Temperature ECT Sensor Circuit Intermittent High Voltage IAT B Circuit High Input

Brand: OLDSMOBILE
Type: P — Powertrain
AI status
Completed
ready
Completed 100%
Page language: EN

Causes

  • Faulty engine coolant temperature (ECT) sensor
  • Open/short or intermittent wiring between sensor and ECU
  • Poor connector connection or corrosion at sensor or ECU
  • Stuck or faulty thermostat causing abnormal coolant temperature behavior
  • Air pocket or low coolant level causing incorrect readings
  • Incorrect sensor installed (wrong type or resistance curve)

Symptoms

  • Illuminated MIL / Check Engine Light
  • Difficult cold starts, extended cranking or poor idle until warm
  • Erratic engine temperature gauge or incorrect dash temperature readings
  • Reduced fuel economy or rich/lean running from incorrect fueling
  • Cooling fan not operating properly or running continuously
  • Possible overheating or poor heater performance

What to check

  • Retrieve freeze frame and live data for ECT, ambient air temp, intake temp and coolant temp during cold start and warm‑up
  • Check for additional related DTCs (P0115, P0116, P0117, P0118, thermostat codes)
  • Visually inspect ECT sensor connector and wiring for corrosion, breaks or damage
  • Measure ECT sensor resistance vs known temperature chart or manufacturer specs
  • Backprobe sensor signal and measure voltage reference and ground with ignition on
  • Verify coolant level and check for air in cooling system; pressurize and inspect for leaks

Signal parameters

  • Sensor type: typically a negative temperature coefficient (NTC) thermistor; resistance decreases as temp rises
  • Typical signal voltage range: 0.0–5.0 V (varies by model and sensor); at cold 2.5–4.5 V, at warm 0.1–1.5 V (manufacturer-specific)
  • Reference supply: usually stable 5 V reference from ECU
  • Expected behavior: smooth monotonic change with temperature and consistent with ambient/engine conditions during warm‑up

Diagnostic algorithm

  1. Verify: Read code, note freeze frame, and check for related codes. Clear code and attempt to reproduce.
  2. Observe live data: With a scan tool monitor ECT, ambient air temp and intake air temp during cold start and warm up. Look for implausible jumps, flatlines or values inconsistent with ambient.
  3. Visual inspection: Check sensor connector for corrosion, bent pins, water intrusion, and secure mounting. Inspect wiring to ECU for damage.
  4. Electrical tests: With ignition on, backprobe: verify ECU 5 V reference present, good ground, and that sensor signal voltage moves with temperature. Check for shorts to power/ground.
  5. Resistance check: Remove sensor and measure resistance at known coolant temperatures (compare to BMW spec or typical NTC curve). Replace if out of spec.
  6. Functional check in‑vehicle: If safe, warm engine and observe ECT change. If ECT reads incorrectly but sensor bench test is good, suspect wiring or ECU.
  7. Cooling system check: Verify coolant level, bleed air from system, and confirm thermostat opens at correct temp — a stuck thermostat can create implausible sensor behavior.
  8. Repair: Replace sensor or repair wiring/connectors as required. If wiring and sensor are good consider ECU/software update or module fault diagnosis.
  9. Confirm: After repair, clear codes and road test to verify correct temperature behavior and that P1115 does not return.

Likely causes

  • Damaged sensor or internal sensor drift
  • Damaged harness (chafing, pinched, water intrusion) between sensor and ECU
  • Loose or corroded sensor connector
  • Thermostat stuck open/closed affecting temperature ramp
  • Low coolant or entrapped air in cooling system

Fault status

⚠️ Status
The engine control module detected an implausible engine coolant temperature signal. The coolant temperature reading is inconsistent with expected values or other sensors. Possible causes include a faulty coolant temperature sensor, wiring/connector faults, thermostat or cooling system issues, or a control module problem.
🟡 Repair difficulty: Medium
⏱️ Diagnostic time: 1.0-3.0 hours

Similar codes

P0115 P0116 P0117 P0118 P0125 P0128
Your experience will help others
+100 karma for a short comment :)
Keep it short and practical. Up to 500 characters.
Send to email
Code

P1115

Other P — Powertrain

Engine Coolant Temperature (ECT) Sensor Circuit Intermittent High Voltage/IAT - B Circuit High Input

Brand: Other
Type: P — Powertrain
AI status
Completed
ready
Completed 100%
Page language: EN

Causes

  • Faulty engine coolant temperature (ECT) sensor
  • Open/short or intermittent wiring between sensor and ECU
  • Poor connector connection or corrosion at sensor or ECU
  • Stuck or faulty thermostat causing abnormal coolant temperature behavior
  • Air pocket or low coolant level causing incorrect readings
  • Incorrect sensor installed (wrong type or resistance curve)

Symptoms

  • Illuminated MIL / Check Engine Light
  • Difficult cold starts, extended cranking or poor idle until warm
  • Erratic engine temperature gauge or incorrect dash temperature readings
  • Reduced fuel economy or rich/lean running from incorrect fueling
  • Cooling fan not operating properly or running continuously
  • Possible overheating or poor heater performance

What to check

  • Retrieve freeze frame and live data for ECT, ambient air temp, intake temp and coolant temp during cold start and warm‑up
  • Check for additional related DTCs (P0115, P0116, P0117, P0118, thermostat codes)
  • Visually inspect ECT sensor connector and wiring for corrosion, breaks or damage
  • Measure ECT sensor resistance vs known temperature chart or manufacturer specs
  • Backprobe sensor signal and measure voltage reference and ground with ignition on
  • Verify coolant level and check for air in cooling system; pressurize and inspect for leaks

Signal parameters

  • Sensor type: typically a negative temperature coefficient (NTC) thermistor; resistance decreases as temp rises
  • Typical signal voltage range: 0.0–5.0 V (varies by model and sensor); at cold 2.5–4.5 V, at warm 0.1–1.5 V (manufacturer-specific)
  • Reference supply: usually stable 5 V reference from ECU
  • Expected behavior: smooth monotonic change with temperature and consistent with ambient/engine conditions during warm‑up

Diagnostic algorithm

  1. Verify: Read code, note freeze frame, and check for related codes. Clear code and attempt to reproduce.
  2. Observe live data: With a scan tool monitor ECT, ambient air temp and intake air temp during cold start and warm up. Look for implausible jumps, flatlines or values inconsistent with ambient.
  3. Visual inspection: Check sensor connector for corrosion, bent pins, water intrusion, and secure mounting. Inspect wiring to ECU for damage.
  4. Electrical tests: With ignition on, backprobe: verify ECU 5 V reference present, good ground, and that sensor signal voltage moves with temperature. Check for shorts to power/ground.
  5. Resistance check: Remove sensor and measure resistance at known coolant temperatures (compare to BMW spec or typical NTC curve). Replace if out of spec.
  6. Functional check in‑vehicle: If safe, warm engine and observe ECT change. If ECT reads incorrectly but sensor bench test is good, suspect wiring or ECU.
  7. Cooling system check: Verify coolant level, bleed air from system, and confirm thermostat opens at correct temp — a stuck thermostat can create implausible sensor behavior.
  8. Repair: Replace sensor or repair wiring/connectors as required. If wiring and sensor are good consider ECU/software update or module fault diagnosis.
  9. Confirm: After repair, clear codes and road test to verify correct temperature behavior and that P1115 does not return.

Likely causes

  • Damaged sensor or internal sensor drift
  • Damaged harness (chafing, pinched, water intrusion) between sensor and ECU
  • Loose or corroded sensor connector
  • Thermostat stuck open/closed affecting temperature ramp
  • Low coolant or entrapped air in cooling system

Fault status

⚠️ Status
The engine control module detected an implausible engine coolant temperature signal. The coolant temperature reading is inconsistent with expected values or other sensors. Possible causes include a faulty coolant temperature sensor, wiring/connector faults, thermostat or cooling system issues, or a control module problem.
🟡 Repair difficulty: Medium
⏱️ Diagnostic time: 1.0-3.0 hours

Similar codes

P0115 P0116 P0117 P0118 P0125 P0128
9,517

The library contains 9,517 repair and diagnostic manuals. Choose a brand to open the full manual tree by year, model and trim.

ALFA ROMEO
89
AUDI
1,243
BMW
479
CADILLAC
206
CHEVROLET
456
CHRYSLER
193
DAEWOO
75
FIAT
26
GENESIS
207
HUMMER
138
HYUNDAI
371
ISUZU
229
KIA
155
LAND ROVER
265
LEXUS
280
LINCOLN
166
MERCEDES-BENZ
856
MERCURY
296
MITSUBISHI
406
PORSCHE
136
TESLA
58
TOYOTA
2,209
TRIUMPH
131
VOLKSWAGEN
626
VOLVO
221
Your experience will help others
+100 karma for a short comment :)
Keep it short and practical. Up to 500 characters.
Send to email
Code

P1115

PEUGEOT P — Powertrain

Upstream oxygen sensor auto-adaptive

Brand: PEUGEOT
Type: P — Powertrain
AI status
Completed
ready
Completed 100%
Page language: EN

Causes

  • Faulty engine coolant temperature (ECT) sensor
  • Open/short or intermittent wiring between sensor and ECU
  • Poor connector connection or corrosion at sensor or ECU
  • Stuck or faulty thermostat causing abnormal coolant temperature behavior
  • Air pocket or low coolant level causing incorrect readings
  • Incorrect sensor installed (wrong type or resistance curve)

Symptoms

  • Illuminated MIL / Check Engine Light
  • Difficult cold starts, extended cranking or poor idle until warm
  • Erratic engine temperature gauge or incorrect dash temperature readings
  • Reduced fuel economy or rich/lean running from incorrect fueling
  • Cooling fan not operating properly or running continuously
  • Possible overheating or poor heater performance

What to check

  • Retrieve freeze frame and live data for ECT, ambient air temp, intake temp and coolant temp during cold start and warm‑up
  • Check for additional related DTCs (P0115, P0116, P0117, P0118, thermostat codes)
  • Visually inspect ECT sensor connector and wiring for corrosion, breaks or damage
  • Measure ECT sensor resistance vs known temperature chart or manufacturer specs
  • Backprobe sensor signal and measure voltage reference and ground with ignition on
  • Verify coolant level and check for air in cooling system; pressurize and inspect for leaks

Signal parameters

  • Sensor type: typically a negative temperature coefficient (NTC) thermistor; resistance decreases as temp rises
  • Typical signal voltage range: 0.0–5.0 V (varies by model and sensor); at cold 2.5–4.5 V, at warm 0.1–1.5 V (manufacturer-specific)
  • Reference supply: usually stable 5 V reference from ECU
  • Expected behavior: smooth monotonic change with temperature and consistent with ambient/engine conditions during warm‑up

Diagnostic algorithm

  1. Verify: Read code, note freeze frame, and check for related codes. Clear code and attempt to reproduce.
  2. Observe live data: With a scan tool monitor ECT, ambient air temp and intake air temp during cold start and warm up. Look for implausible jumps, flatlines or values inconsistent with ambient.
  3. Visual inspection: Check sensor connector for corrosion, bent pins, water intrusion, and secure mounting. Inspect wiring to ECU for damage.
  4. Electrical tests: With ignition on, backprobe: verify ECU 5 V reference present, good ground, and that sensor signal voltage moves with temperature. Check for shorts to power/ground.
  5. Resistance check: Remove sensor and measure resistance at known coolant temperatures (compare to BMW spec or typical NTC curve). Replace if out of spec.
  6. Functional check in‑vehicle: If safe, warm engine and observe ECT change. If ECT reads incorrectly but sensor bench test is good, suspect wiring or ECU.
  7. Cooling system check: Verify coolant level, bleed air from system, and confirm thermostat opens at correct temp — a stuck thermostat can create implausible sensor behavior.
  8. Repair: Replace sensor or repair wiring/connectors as required. If wiring and sensor are good consider ECU/software update or module fault diagnosis.
  9. Confirm: After repair, clear codes and road test to verify correct temperature behavior and that P1115 does not return.

Likely causes

  • Damaged sensor or internal sensor drift
  • Damaged harness (chafing, pinched, water intrusion) between sensor and ECU
  • Loose or corroded sensor connector
  • Thermostat stuck open/closed affecting temperature ramp
  • Low coolant or entrapped air in cooling system

Fault status

⚠️ Status
The engine control module detected an implausible engine coolant temperature signal. The coolant temperature reading is inconsistent with expected values or other sensors. Possible causes include a faulty coolant temperature sensor, wiring/connector faults, thermostat or cooling system issues, or a control module problem.
🟡 Repair difficulty: Medium
⏱️ Diagnostic time: 1.0-3.0 hours

Similar codes

P0115 P0116 P0117 P0118 P0125 P0128
Your experience will help others
+100 karma for a short comment :)
Keep it short and practical. Up to 500 characters.
Send to email
Code

P1115

PORSCHE P — Powertrain

Heating of HO2S 1 ahead of TWC

Brand: PORSCHE
Type: P — Powertrain
AI status
Completed
ready
Completed 100%
Page language: EN

Causes

  • Faulty engine coolant temperature (ECT) sensor
  • Open/short or intermittent wiring between sensor and ECU
  • Poor connector connection or corrosion at sensor or ECU
  • Stuck or faulty thermostat causing abnormal coolant temperature behavior
  • Air pocket or low coolant level causing incorrect readings
  • Incorrect sensor installed (wrong type or resistance curve)

Symptoms

  • Illuminated MIL / Check Engine Light
  • Difficult cold starts, extended cranking or poor idle until warm
  • Erratic engine temperature gauge or incorrect dash temperature readings
  • Reduced fuel economy or rich/lean running from incorrect fueling
  • Cooling fan not operating properly or running continuously
  • Possible overheating or poor heater performance

What to check

  • Retrieve freeze frame and live data for ECT, ambient air temp, intake temp and coolant temp during cold start and warm‑up
  • Check for additional related DTCs (P0115, P0116, P0117, P0118, thermostat codes)
  • Visually inspect ECT sensor connector and wiring for corrosion, breaks or damage
  • Measure ECT sensor resistance vs known temperature chart or manufacturer specs
  • Backprobe sensor signal and measure voltage reference and ground with ignition on
  • Verify coolant level and check for air in cooling system; pressurize and inspect for leaks

Signal parameters

  • Sensor type: typically a negative temperature coefficient (NTC) thermistor; resistance decreases as temp rises
  • Typical signal voltage range: 0.0–5.0 V (varies by model and sensor); at cold 2.5–4.5 V, at warm 0.1–1.5 V (manufacturer-specific)
  • Reference supply: usually stable 5 V reference from ECU
  • Expected behavior: smooth monotonic change with temperature and consistent with ambient/engine conditions during warm‑up

Diagnostic algorithm

  1. Verify: Read code, note freeze frame, and check for related codes. Clear code and attempt to reproduce.
  2. Observe live data: With a scan tool monitor ECT, ambient air temp and intake air temp during cold start and warm up. Look for implausible jumps, flatlines or values inconsistent with ambient.
  3. Visual inspection: Check sensor connector for corrosion, bent pins, water intrusion, and secure mounting. Inspect wiring to ECU for damage.
  4. Electrical tests: With ignition on, backprobe: verify ECU 5 V reference present, good ground, and that sensor signal voltage moves with temperature. Check for shorts to power/ground.
  5. Resistance check: Remove sensor and measure resistance at known coolant temperatures (compare to BMW spec or typical NTC curve). Replace if out of spec.
  6. Functional check in‑vehicle: If safe, warm engine and observe ECT change. If ECT reads incorrectly but sensor bench test is good, suspect wiring or ECU.
  7. Cooling system check: Verify coolant level, bleed air from system, and confirm thermostat opens at correct temp — a stuck thermostat can create implausible sensor behavior.
  8. Repair: Replace sensor or repair wiring/connectors as required. If wiring and sensor are good consider ECU/software update or module fault diagnosis.
  9. Confirm: After repair, clear codes and road test to verify correct temperature behavior and that P1115 does not return.

Likely causes

  • Damaged sensor or internal sensor drift
  • Damaged harness (chafing, pinched, water intrusion) between sensor and ECU
  • Loose or corroded sensor connector
  • Thermostat stuck open/closed affecting temperature ramp
  • Low coolant or entrapped air in cooling system

Fault status

⚠️ Status
The engine control module detected an implausible engine coolant temperature signal. The coolant temperature reading is inconsistent with expected values or other sensors. Possible causes include a faulty coolant temperature sensor, wiring/connector faults, thermostat or cooling system issues, or a control module problem.
🟡 Repair difficulty: Medium
⏱️ Diagnostic time: 1.0-3.0 hours

Similar codes

P0115 P0116 P0117 P0118 P0125 P0128
136

Browse 136 PORSCHE manuals: repair procedures, diagnostics, wiring diagrams, component locations, service data and Labor Times by year, model and trim.

PORSCHE

Your experience will help others
+100 karma for a short comment :)
Keep it short and practical. Up to 500 characters.
Send to email
Code

P1115

RAM P — Powertrain

General Temperature Rationality

Brand: RAM
Type: P — Powertrain
AI status
Completed
ready
Completed 100%
Page language: EN

Causes

  • Faulty engine coolant temperature (ECT) sensor
  • Open/short or intermittent wiring between sensor and ECU
  • Poor connector connection or corrosion at sensor or ECU
  • Stuck or faulty thermostat causing abnormal coolant temperature behavior
  • Air pocket or low coolant level causing incorrect readings
  • Incorrect sensor installed (wrong type or resistance curve)

Symptoms

  • Illuminated MIL / Check Engine Light
  • Difficult cold starts, extended cranking or poor idle until warm
  • Erratic engine temperature gauge or incorrect dash temperature readings
  • Reduced fuel economy or rich/lean running from incorrect fueling
  • Cooling fan not operating properly or running continuously
  • Possible overheating or poor heater performance

What to check

  • Retrieve freeze frame and live data for ECT, ambient air temp, intake temp and coolant temp during cold start and warm‑up
  • Check for additional related DTCs (P0115, P0116, P0117, P0118, thermostat codes)
  • Visually inspect ECT sensor connector and wiring for corrosion, breaks or damage
  • Measure ECT sensor resistance vs known temperature chart or manufacturer specs
  • Backprobe sensor signal and measure voltage reference and ground with ignition on
  • Verify coolant level and check for air in cooling system; pressurize and inspect for leaks

Signal parameters

  • Sensor type: typically a negative temperature coefficient (NTC) thermistor; resistance decreases as temp rises
  • Typical signal voltage range: 0.0–5.0 V (varies by model and sensor); at cold 2.5–4.5 V, at warm 0.1–1.5 V (manufacturer-specific)
  • Reference supply: usually stable 5 V reference from ECU
  • Expected behavior: smooth monotonic change with temperature and consistent with ambient/engine conditions during warm‑up

Diagnostic algorithm

  1. Verify: Read code, note freeze frame, and check for related codes. Clear code and attempt to reproduce.
  2. Observe live data: With a scan tool monitor ECT, ambient air temp and intake air temp during cold start and warm up. Look for implausible jumps, flatlines or values inconsistent with ambient.
  3. Visual inspection: Check sensor connector for corrosion, bent pins, water intrusion, and secure mounting. Inspect wiring to ECU for damage.
  4. Electrical tests: With ignition on, backprobe: verify ECU 5 V reference present, good ground, and that sensor signal voltage moves with temperature. Check for shorts to power/ground.
  5. Resistance check: Remove sensor and measure resistance at known coolant temperatures (compare to BMW spec or typical NTC curve). Replace if out of spec.
  6. Functional check in‑vehicle: If safe, warm engine and observe ECT change. If ECT reads incorrectly but sensor bench test is good, suspect wiring or ECU.
  7. Cooling system check: Verify coolant level, bleed air from system, and confirm thermostat opens at correct temp — a stuck thermostat can create implausible sensor behavior.
  8. Repair: Replace sensor or repair wiring/connectors as required. If wiring and sensor are good consider ECU/software update or module fault diagnosis.
  9. Confirm: After repair, clear codes and road test to verify correct temperature behavior and that P1115 does not return.

Likely causes

  • Damaged sensor or internal sensor drift
  • Damaged harness (chafing, pinched, water intrusion) between sensor and ECU
  • Loose or corroded sensor connector
  • Thermostat stuck open/closed affecting temperature ramp
  • Low coolant or entrapped air in cooling system

Fault status

⚠️ Status
The engine control module detected an implausible engine coolant temperature signal. The coolant temperature reading is inconsistent with expected values or other sensors. Possible causes include a faulty coolant temperature sensor, wiring/connector faults, thermostat or cooling system issues, or a control module problem.
🟡 Repair difficulty: Medium
⏱️ Diagnostic time: 1.0-3.0 hours

Similar codes

P0115 P0116 P0117 P0118 P0125 P0128
Your experience will help others
+100 karma for a short comment :)
Keep it short and practical. Up to 500 characters.
Send to email
Code

P1115

SAAB P — Powertrain

Front HO2S Bank 1, Control Module Input, Current in Pre-Heating Circuit Too Low

Brand: SAAB
Type: P — Powertrain
AI status
Completed
ready
Completed 100%
Page language: EN

Causes

  • Faulty engine coolant temperature (ECT) sensor
  • Open/short or intermittent wiring between sensor and ECU
  • Poor connector connection or corrosion at sensor or ECU
  • Stuck or faulty thermostat causing abnormal coolant temperature behavior
  • Air pocket or low coolant level causing incorrect readings
  • Incorrect sensor installed (wrong type or resistance curve)

Symptoms

  • Illuminated MIL / Check Engine Light
  • Difficult cold starts, extended cranking or poor idle until warm
  • Erratic engine temperature gauge or incorrect dash temperature readings
  • Reduced fuel economy or rich/lean running from incorrect fueling
  • Cooling fan not operating properly or running continuously
  • Possible overheating or poor heater performance

What to check

  • Retrieve freeze frame and live data for ECT, ambient air temp, intake temp and coolant temp during cold start and warm‑up
  • Check for additional related DTCs (P0115, P0116, P0117, P0118, thermostat codes)
  • Visually inspect ECT sensor connector and wiring for corrosion, breaks or damage
  • Measure ECT sensor resistance vs known temperature chart or manufacturer specs
  • Backprobe sensor signal and measure voltage reference and ground with ignition on
  • Verify coolant level and check for air in cooling system; pressurize and inspect for leaks

Signal parameters

  • Sensor type: typically a negative temperature coefficient (NTC) thermistor; resistance decreases as temp rises
  • Typical signal voltage range: 0.0–5.0 V (varies by model and sensor); at cold 2.5–4.5 V, at warm 0.1–1.5 V (manufacturer-specific)
  • Reference supply: usually stable 5 V reference from ECU
  • Expected behavior: smooth monotonic change with temperature and consistent with ambient/engine conditions during warm‑up

Diagnostic algorithm

  1. Verify: Read code, note freeze frame, and check for related codes. Clear code and attempt to reproduce.
  2. Observe live data: With a scan tool monitor ECT, ambient air temp and intake air temp during cold start and warm up. Look for implausible jumps, flatlines or values inconsistent with ambient.
  3. Visual inspection: Check sensor connector for corrosion, bent pins, water intrusion, and secure mounting. Inspect wiring to ECU for damage.
  4. Electrical tests: With ignition on, backprobe: verify ECU 5 V reference present, good ground, and that sensor signal voltage moves with temperature. Check for shorts to power/ground.
  5. Resistance check: Remove sensor and measure resistance at known coolant temperatures (compare to BMW spec or typical NTC curve). Replace if out of spec.
  6. Functional check in‑vehicle: If safe, warm engine and observe ECT change. If ECT reads incorrectly but sensor bench test is good, suspect wiring or ECU.
  7. Cooling system check: Verify coolant level, bleed air from system, and confirm thermostat opens at correct temp — a stuck thermostat can create implausible sensor behavior.
  8. Repair: Replace sensor or repair wiring/connectors as required. If wiring and sensor are good consider ECU/software update or module fault diagnosis.
  9. Confirm: After repair, clear codes and road test to verify correct temperature behavior and that P1115 does not return.

Likely causes

  • Damaged sensor or internal sensor drift
  • Damaged harness (chafing, pinched, water intrusion) between sensor and ECU
  • Loose or corroded sensor connector
  • Thermostat stuck open/closed affecting temperature ramp
  • Low coolant or entrapped air in cooling system

Fault status

⚠️ Status
The engine control module detected an implausible engine coolant temperature signal. The coolant temperature reading is inconsistent with expected values or other sensors. Possible causes include a faulty coolant temperature sensor, wiring/connector faults, thermostat or cooling system issues, or a control module problem.
🟡 Repair difficulty: Medium
⏱️ Diagnostic time: 1.0-3.0 hours

Similar codes

P0115 P0116 P0117 P0118 P0125 P0128
Your experience will help others
+100 karma for a short comment :)
Keep it short and practical. Up to 500 characters.
Send to email
Code

P1115

SATURN P — Powertrain

Engine Coolant Temperature ECT Sensor Circuit Intermittent High Voltage

Brand: SATURN
Type: P — Powertrain
AI status
Completed
ready
Completed 100%
Page language: EN

Causes

  • Faulty engine coolant temperature (ECT) sensor
  • Open/short or intermittent wiring between sensor and ECU
  • Poor connector connection or corrosion at sensor or ECU
  • Stuck or faulty thermostat causing abnormal coolant temperature behavior
  • Air pocket or low coolant level causing incorrect readings
  • Incorrect sensor installed (wrong type or resistance curve)

Symptoms

  • Illuminated MIL / Check Engine Light
  • Difficult cold starts, extended cranking or poor idle until warm
  • Erratic engine temperature gauge or incorrect dash temperature readings
  • Reduced fuel economy or rich/lean running from incorrect fueling
  • Cooling fan not operating properly or running continuously
  • Possible overheating or poor heater performance

What to check

  • Retrieve freeze frame and live data for ECT, ambient air temp, intake temp and coolant temp during cold start and warm‑up
  • Check for additional related DTCs (P0115, P0116, P0117, P0118, thermostat codes)
  • Visually inspect ECT sensor connector and wiring for corrosion, breaks or damage
  • Measure ECT sensor resistance vs known temperature chart or manufacturer specs
  • Backprobe sensor signal and measure voltage reference and ground with ignition on
  • Verify coolant level and check for air in cooling system; pressurize and inspect for leaks

Signal parameters

  • Sensor type: typically a negative temperature coefficient (NTC) thermistor; resistance decreases as temp rises
  • Typical signal voltage range: 0.0–5.0 V (varies by model and sensor); at cold 2.5–4.5 V, at warm 0.1–1.5 V (manufacturer-specific)
  • Reference supply: usually stable 5 V reference from ECU
  • Expected behavior: smooth monotonic change with temperature and consistent with ambient/engine conditions during warm‑up

Diagnostic algorithm

  1. Verify: Read code, note freeze frame, and check for related codes. Clear code and attempt to reproduce.
  2. Observe live data: With a scan tool monitor ECT, ambient air temp and intake air temp during cold start and warm up. Look for implausible jumps, flatlines or values inconsistent with ambient.
  3. Visual inspection: Check sensor connector for corrosion, bent pins, water intrusion, and secure mounting. Inspect wiring to ECU for damage.
  4. Electrical tests: With ignition on, backprobe: verify ECU 5 V reference present, good ground, and that sensor signal voltage moves with temperature. Check for shorts to power/ground.
  5. Resistance check: Remove sensor and measure resistance at known coolant temperatures (compare to BMW spec or typical NTC curve). Replace if out of spec.
  6. Functional check in‑vehicle: If safe, warm engine and observe ECT change. If ECT reads incorrectly but sensor bench test is good, suspect wiring or ECU.
  7. Cooling system check: Verify coolant level, bleed air from system, and confirm thermostat opens at correct temp — a stuck thermostat can create implausible sensor behavior.
  8. Repair: Replace sensor or repair wiring/connectors as required. If wiring and sensor are good consider ECU/software update or module fault diagnosis.
  9. Confirm: After repair, clear codes and road test to verify correct temperature behavior and that P1115 does not return.

Likely causes

  • Damaged sensor or internal sensor drift
  • Damaged harness (chafing, pinched, water intrusion) between sensor and ECU
  • Loose or corroded sensor connector
  • Thermostat stuck open/closed affecting temperature ramp
  • Low coolant or entrapped air in cooling system

Fault status

⚠️ Status
The engine control module detected an implausible engine coolant temperature signal. The coolant temperature reading is inconsistent with expected values or other sensors. Possible causes include a faulty coolant temperature sensor, wiring/connector faults, thermostat or cooling system issues, or a control module problem.
🟡 Repair difficulty: Medium
⏱️ Diagnostic time: 1.0-3.0 hours

Similar codes

P0115 P0116 P0117 P0118 P0125 P0128
Your experience will help others
+100 karma for a short comment :)
Keep it short and practical. Up to 500 characters.
Send to email
Code

P1115

SUBARU P — Powertrain

Engine Torque Control Cut Signal Circuit High Input

Brand: SUBARU
Type: P — Powertrain
AI status
Completed
ready
Completed 100%
Page language: EN

Causes

  • Faulty engine coolant temperature (ECT) sensor
  • Open/short or intermittent wiring between sensor and ECU
  • Poor connector connection or corrosion at sensor or ECU
  • Stuck or faulty thermostat causing abnormal coolant temperature behavior
  • Air pocket or low coolant level causing incorrect readings
  • Incorrect sensor installed (wrong type or resistance curve)

Symptoms

  • Illuminated MIL / Check Engine Light
  • Difficult cold starts, extended cranking or poor idle until warm
  • Erratic engine temperature gauge or incorrect dash temperature readings
  • Reduced fuel economy or rich/lean running from incorrect fueling
  • Cooling fan not operating properly or running continuously
  • Possible overheating or poor heater performance

What to check

  • Retrieve freeze frame and live data for ECT, ambient air temp, intake temp and coolant temp during cold start and warm‑up
  • Check for additional related DTCs (P0115, P0116, P0117, P0118, thermostat codes)
  • Visually inspect ECT sensor connector and wiring for corrosion, breaks or damage
  • Measure ECT sensor resistance vs known temperature chart or manufacturer specs
  • Backprobe sensor signal and measure voltage reference and ground with ignition on
  • Verify coolant level and check for air in cooling system; pressurize and inspect for leaks

Signal parameters

  • Sensor type: typically a negative temperature coefficient (NTC) thermistor; resistance decreases as temp rises
  • Typical signal voltage range: 0.0–5.0 V (varies by model and sensor); at cold 2.5–4.5 V, at warm 0.1–1.5 V (manufacturer-specific)
  • Reference supply: usually stable 5 V reference from ECU
  • Expected behavior: smooth monotonic change with temperature and consistent with ambient/engine conditions during warm‑up

Diagnostic algorithm

  1. Verify: Read code, note freeze frame, and check for related codes. Clear code and attempt to reproduce.
  2. Observe live data: With a scan tool monitor ECT, ambient air temp and intake air temp during cold start and warm up. Look for implausible jumps, flatlines or values inconsistent with ambient.
  3. Visual inspection: Check sensor connector for corrosion, bent pins, water intrusion, and secure mounting. Inspect wiring to ECU for damage.
  4. Electrical tests: With ignition on, backprobe: verify ECU 5 V reference present, good ground, and that sensor signal voltage moves with temperature. Check for shorts to power/ground.
  5. Resistance check: Remove sensor and measure resistance at known coolant temperatures (compare to BMW spec or typical NTC curve). Replace if out of spec.
  6. Functional check in‑vehicle: If safe, warm engine and observe ECT change. If ECT reads incorrectly but sensor bench test is good, suspect wiring or ECU.
  7. Cooling system check: Verify coolant level, bleed air from system, and confirm thermostat opens at correct temp — a stuck thermostat can create implausible sensor behavior.
  8. Repair: Replace sensor or repair wiring/connectors as required. If wiring and sensor are good consider ECU/software update or module fault diagnosis.
  9. Confirm: After repair, clear codes and road test to verify correct temperature behavior and that P1115 does not return.

Likely causes

  • Damaged sensor or internal sensor drift
  • Damaged harness (chafing, pinched, water intrusion) between sensor and ECU
  • Loose or corroded sensor connector
  • Thermostat stuck open/closed affecting temperature ramp
  • Low coolant or entrapped air in cooling system

Fault status

⚠️ Status
The engine control module detected an implausible engine coolant temperature signal. The coolant temperature reading is inconsistent with expected values or other sensors. Possible causes include a faulty coolant temperature sensor, wiring/connector faults, thermostat or cooling system issues, or a control module problem.
🟡 Repair difficulty: Medium
⏱️ Diagnostic time: 1.0-3.0 hours

Similar codes

P0115 P0116 P0117 P0118 P0125 P0128
Your experience will help others
+100 karma for a short comment :)
Keep it short and practical. Up to 500 characters.
Send to email
Code

P1115

VOLKSWAGEN P — Powertrain

Oxygen Sensor Heater Circuit Short To Ground Bank 1 Sensor 1

Brand: VOLKSWAGEN
Type: P — Powertrain
AI status
Completed
ready
Completed 100%
Page language: EN

Causes

  • Faulty engine coolant temperature (ECT) sensor
  • Open/short or intermittent wiring between sensor and ECU
  • Poor connector connection or corrosion at sensor or ECU
  • Stuck or faulty thermostat causing abnormal coolant temperature behavior
  • Air pocket or low coolant level causing incorrect readings
  • Incorrect sensor installed (wrong type or resistance curve)

Symptoms

  • Illuminated MIL / Check Engine Light
  • Difficult cold starts, extended cranking or poor idle until warm
  • Erratic engine temperature gauge or incorrect dash temperature readings
  • Reduced fuel economy or rich/lean running from incorrect fueling
  • Cooling fan not operating properly or running continuously
  • Possible overheating or poor heater performance

What to check

  • Retrieve freeze frame and live data for ECT, ambient air temp, intake temp and coolant temp during cold start and warm‑up
  • Check for additional related DTCs (P0115, P0116, P0117, P0118, thermostat codes)
  • Visually inspect ECT sensor connector and wiring for corrosion, breaks or damage
  • Measure ECT sensor resistance vs known temperature chart or manufacturer specs
  • Backprobe sensor signal and measure voltage reference and ground with ignition on
  • Verify coolant level and check for air in cooling system; pressurize and inspect for leaks

Signal parameters

  • Sensor type: typically a negative temperature coefficient (NTC) thermistor; resistance decreases as temp rises
  • Typical signal voltage range: 0.0–5.0 V (varies by model and sensor); at cold 2.5–4.5 V, at warm 0.1–1.5 V (manufacturer-specific)
  • Reference supply: usually stable 5 V reference from ECU
  • Expected behavior: smooth monotonic change with temperature and consistent with ambient/engine conditions during warm‑up

Diagnostic algorithm

  1. Verify: Read code, note freeze frame, and check for related codes. Clear code and attempt to reproduce.
  2. Observe live data: With a scan tool monitor ECT, ambient air temp and intake air temp during cold start and warm up. Look for implausible jumps, flatlines or values inconsistent with ambient.
  3. Visual inspection: Check sensor connector for corrosion, bent pins, water intrusion, and secure mounting. Inspect wiring to ECU for damage.
  4. Electrical tests: With ignition on, backprobe: verify ECU 5 V reference present, good ground, and that sensor signal voltage moves with temperature. Check for shorts to power/ground.
  5. Resistance check: Remove sensor and measure resistance at known coolant temperatures (compare to BMW spec or typical NTC curve). Replace if out of spec.
  6. Functional check in‑vehicle: If safe, warm engine and observe ECT change. If ECT reads incorrectly but sensor bench test is good, suspect wiring or ECU.
  7. Cooling system check: Verify coolant level, bleed air from system, and confirm thermostat opens at correct temp — a stuck thermostat can create implausible sensor behavior.
  8. Repair: Replace sensor or repair wiring/connectors as required. If wiring and sensor are good consider ECU/software update or module fault diagnosis.
  9. Confirm: After repair, clear codes and road test to verify correct temperature behavior and that P1115 does not return.

Likely causes

  • Damaged sensor or internal sensor drift
  • Damaged harness (chafing, pinched, water intrusion) between sensor and ECU
  • Loose or corroded sensor connector
  • Thermostat stuck open/closed affecting temperature ramp
  • Low coolant or entrapped air in cooling system

Fault status

⚠️ Status
The engine control module detected an implausible engine coolant temperature signal. The coolant temperature reading is inconsistent with expected values or other sensors. Possible causes include a faulty coolant temperature sensor, wiring/connector faults, thermostat or cooling system issues, or a control module problem.
🟡 Repair difficulty: Medium
⏱️ Diagnostic time: 1.0-3.0 hours

Similar codes

P0115 P0116 P0117 P0118 P0125 P0128
626

Browse 626 VOLKSWAGEN manuals: repair procedures, diagnostics, wiring diagrams, component locations, service data and Labor Times by year, model and trim.

VOLKSWAGEN

Your experience will help others
+100 karma for a short comment :)
Keep it short and practical. Up to 500 characters.
Send to email

Report

Harassment or bullying behavior
Contains mature or sensitive content
Contains misleading or false information
Contains abusive or derogatory content
Contains spam, fake content or potential malware

Block Member?

Please confirm you want to block this member.

You will no longer be able to:

  • See blocked member's posts
  • Mention this member in posts
  • Invite this member to groups
  • Message this member
  • Add this member as a connection

Please note: This action will also remove this member from your connections and send a report to the site admin. Please allow a few minutes for this process to complete.

Report

You have already reported this .