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Home / DTC / P1188 — Fuel Control Bank 1 Sensor 1

P1188 — Fuel Control Bank 1 Sensor 1

Detailed page for trouble code P1188.

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Code

P1188

BMW P — Powertrain

Fuel Control Bank 1 Sensor 1

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

Causes

  • Faulty Bank 1 Sensor 1 (upstream O2/AFR sensor)
  • Damaged wiring or poor connector contact to the sensor
  • Heater circuit failure in the sensor
  • Exhaust leaks upstream of the sensor (false air)
  • Fuel pressure or injector problems causing out-of-range AFR
  • Contaminated sensor (oil, coolant, silicone)

Symptoms

  • Check Engine Light (MIL) on
  • Poor idle quality or rough running
  • Elevated or unstable fuel trims (long or short term)
  • Reduced fuel economy
  • Hesitation, stumble or reduced drivability under load
  • Possible hard starting or stalling

What to check

  • Read freeze frame and stored data for fuel trims and sensor values
  • Scan live upstream O2/AFR sensor (Bank 1 Sensor 1) voltage or AFR trace
  • Check for additional DTCs (fuel trims, injector, MAP/MAF, fuel pressure, leaks)
  • Inspect sensor connector for corrosion, damage, or moisture
  • Visually inspect wiring harness for chafing, pinches or breaks
  • Perform smoke test or visual check for vacuum/exhaust leaks upstream of sensor

Signal parameters

  • Typical narrowband upstream O2 voltage: ~0.1–0.9 V (switching rapidly around 0.45 V)
  • Heater circuit: resistance typically low ohms (varies by sensor, often ~2–10 Ω) — consult vehicle spec
  • Sensor should switch rich/lean quickly at idle; slow or fixed readings indicate fault
  • Wideband/AFR sensors (if fitted) use different signal ranges — consult OEM spec for voltage/current/serial data

Diagnostic algorithm

  1. Connect a full-function OBD-II scanner and record freeze frame, stored codes and live data for Bank 1 Sensor 1 and fuel trims
  2. Confirm P1188 is current and note accompanying codes that narrow cause (fuel trims, injector, MAF, MAP, fuel pressure)
  3. With engine warm at idle, observe Bank 1 Sensor 1 waveform or AFR: a healthy narrowband sensor should switch regularly; wideband should follow commanded AFR
  4. Inspect sensor connector and wiring. Wiggle test harness while monitoring live data for intermittent changes
  5. Measure heater circuit: with connector disconnected measure resistance between heater pins and to ground for shorts; with ignition on measure heater supply voltage (consult wiring diagram)
  6. Check continuity between sensor pins and ECU connector; repair any opens/shorts
  7. Perform smoke/leak test of intake/exhaust for leaks upstream of the sensor and correct leaks found
  8. Verify fuel pressure and injector operation to ensure proper fueling; repair fuel-system faults
  9. If wiring and fuel system are good and sensor signals out of spec, replace Bank 1 Sensor 1 with OEM-equivalent and clear codes
  10. After repair, erase codes and perform road test / monitor live data to confirm normal sensor switching and normalized fuel trims

Likely causes

  • Failed or degraded Bank 1 Sensor 1
  • Open/short or intermittent wiring/connector to the sensor
  • Heater element open or no power to heater circuit
  • Vacuum/exhaust leak upstream of the sensor causing incorrect readings
  • Low/high fuel pressure or injector fault affecting AFR

Fault status

⚠️ Status
Fuel control fault detected on Bank 1 Sensor 1 — upstream oxygen/AFR sensor signal or heater circuit out of specification, affecting closed-loop fuel control.
🟡 Repair difficulty: Medium
⏱️ Diagnostic time: 1-2 hours

Similar codes

P0130 P0131 P0132 P0133 P0134 P0135
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Code

P1188

BUICK P — Powertrain

EOT Sensor Circuit High Voltage

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

Causes

  • Faulty Bank 1 Sensor 1 (upstream O2/AFR sensor)
  • Damaged wiring or poor connector contact to the sensor
  • Heater circuit failure in the sensor
  • Exhaust leaks upstream of the sensor (false air)
  • Fuel pressure or injector problems causing out-of-range AFR
  • Contaminated sensor (oil, coolant, silicone)

Symptoms

  • Check Engine Light (MIL) on
  • Poor idle quality or rough running
  • Elevated or unstable fuel trims (long or short term)
  • Reduced fuel economy
  • Hesitation, stumble or reduced drivability under load
  • Possible hard starting or stalling

What to check

  • Read freeze frame and stored data for fuel trims and sensor values
  • Scan live upstream O2/AFR sensor (Bank 1 Sensor 1) voltage or AFR trace
  • Check for additional DTCs (fuel trims, injector, MAP/MAF, fuel pressure, leaks)
  • Inspect sensor connector for corrosion, damage, or moisture
  • Visually inspect wiring harness for chafing, pinches or breaks
  • Perform smoke test or visual check for vacuum/exhaust leaks upstream of sensor

Signal parameters

  • Typical narrowband upstream O2 voltage: ~0.1–0.9 V (switching rapidly around 0.45 V)
  • Heater circuit: resistance typically low ohms (varies by sensor, often ~2–10 Ω) — consult vehicle spec
  • Sensor should switch rich/lean quickly at idle; slow or fixed readings indicate fault
  • Wideband/AFR sensors (if fitted) use different signal ranges — consult OEM spec for voltage/current/serial data

Diagnostic algorithm

  1. Connect a full-function OBD-II scanner and record freeze frame, stored codes and live data for Bank 1 Sensor 1 and fuel trims
  2. Confirm P1188 is current and note accompanying codes that narrow cause (fuel trims, injector, MAF, MAP, fuel pressure)
  3. With engine warm at idle, observe Bank 1 Sensor 1 waveform or AFR: a healthy narrowband sensor should switch regularly; wideband should follow commanded AFR
  4. Inspect sensor connector and wiring. Wiggle test harness while monitoring live data for intermittent changes
  5. Measure heater circuit: with connector disconnected measure resistance between heater pins and to ground for shorts; with ignition on measure heater supply voltage (consult wiring diagram)
  6. Check continuity between sensor pins and ECU connector; repair any opens/shorts
  7. Perform smoke/leak test of intake/exhaust for leaks upstream of the sensor and correct leaks found
  8. Verify fuel pressure and injector operation to ensure proper fueling; repair fuel-system faults
  9. If wiring and fuel system are good and sensor signals out of spec, replace Bank 1 Sensor 1 with OEM-equivalent and clear codes
  10. After repair, erase codes and perform road test / monitor live data to confirm normal sensor switching and normalized fuel trims

Likely causes

  • Failed or degraded Bank 1 Sensor 1
  • Open/short or intermittent wiring/connector to the sensor
  • Heater element open or no power to heater circuit
  • Vacuum/exhaust leak upstream of the sensor causing incorrect readings
  • Low/high fuel pressure or injector fault affecting AFR

Fault status

⚠️ Status
Fuel control fault detected on Bank 1 Sensor 1 — upstream oxygen/AFR sensor signal or heater circuit out of specification, affecting closed-loop fuel control.
🟡 Repair difficulty: Medium
⏱️ Diagnostic time: 1-2 hours

Similar codes

P0130 P0131 P0132 P0133 P0134 P0135
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Code

P1188

CADILLAC P — Powertrain

EOT Sensor Circuit High Voltage

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

Causes

  • Faulty Bank 1 Sensor 1 (upstream O2/AFR sensor)
  • Damaged wiring or poor connector contact to the sensor
  • Heater circuit failure in the sensor
  • Exhaust leaks upstream of the sensor (false air)
  • Fuel pressure or injector problems causing out-of-range AFR
  • Contaminated sensor (oil, coolant, silicone)

Symptoms

  • Check Engine Light (MIL) on
  • Poor idle quality or rough running
  • Elevated or unstable fuel trims (long or short term)
  • Reduced fuel economy
  • Hesitation, stumble or reduced drivability under load
  • Possible hard starting or stalling

What to check

  • Read freeze frame and stored data for fuel trims and sensor values
  • Scan live upstream O2/AFR sensor (Bank 1 Sensor 1) voltage or AFR trace
  • Check for additional DTCs (fuel trims, injector, MAP/MAF, fuel pressure, leaks)
  • Inspect sensor connector for corrosion, damage, or moisture
  • Visually inspect wiring harness for chafing, pinches or breaks
  • Perform smoke test or visual check for vacuum/exhaust leaks upstream of sensor

Signal parameters

  • Typical narrowband upstream O2 voltage: ~0.1–0.9 V (switching rapidly around 0.45 V)
  • Heater circuit: resistance typically low ohms (varies by sensor, often ~2–10 Ω) — consult vehicle spec
  • Sensor should switch rich/lean quickly at idle; slow or fixed readings indicate fault
  • Wideband/AFR sensors (if fitted) use different signal ranges — consult OEM spec for voltage/current/serial data

Diagnostic algorithm

  1. Connect a full-function OBD-II scanner and record freeze frame, stored codes and live data for Bank 1 Sensor 1 and fuel trims
  2. Confirm P1188 is current and note accompanying codes that narrow cause (fuel trims, injector, MAF, MAP, fuel pressure)
  3. With engine warm at idle, observe Bank 1 Sensor 1 waveform or AFR: a healthy narrowband sensor should switch regularly; wideband should follow commanded AFR
  4. Inspect sensor connector and wiring. Wiggle test harness while monitoring live data for intermittent changes
  5. Measure heater circuit: with connector disconnected measure resistance between heater pins and to ground for shorts; with ignition on measure heater supply voltage (consult wiring diagram)
  6. Check continuity between sensor pins and ECU connector; repair any opens/shorts
  7. Perform smoke/leak test of intake/exhaust for leaks upstream of the sensor and correct leaks found
  8. Verify fuel pressure and injector operation to ensure proper fueling; repair fuel-system faults
  9. If wiring and fuel system are good and sensor signals out of spec, replace Bank 1 Sensor 1 with OEM-equivalent and clear codes
  10. After repair, erase codes and perform road test / monitor live data to confirm normal sensor switching and normalized fuel trims

Likely causes

  • Failed or degraded Bank 1 Sensor 1
  • Open/short or intermittent wiring/connector to the sensor
  • Heater element open or no power to heater circuit
  • Vacuum/exhaust leak upstream of the sensor causing incorrect readings
  • Low/high fuel pressure or injector fault affecting AFR

Fault status

⚠️ Status
Fuel control fault detected on Bank 1 Sensor 1 — upstream oxygen/AFR sensor signal or heater circuit out of specification, affecting closed-loop fuel control.
🟡 Repair difficulty: Medium
⏱️ Diagnostic time: 1-2 hours

Similar codes

P0130 P0131 P0132 P0133 P0134 P0135
206

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Code

P1188

CHEVROLET P — Powertrain

EOT Sensor Circuit High Voltage

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

Causes

  • Faulty Bank 1 Sensor 1 (upstream O2/AFR sensor)
  • Damaged wiring or poor connector contact to the sensor
  • Heater circuit failure in the sensor
  • Exhaust leaks upstream of the sensor (false air)
  • Fuel pressure or injector problems causing out-of-range AFR
  • Contaminated sensor (oil, coolant, silicone)

Symptoms

  • Check Engine Light (MIL) on
  • Poor idle quality or rough running
  • Elevated or unstable fuel trims (long or short term)
  • Reduced fuel economy
  • Hesitation, stumble or reduced drivability under load
  • Possible hard starting or stalling

What to check

  • Read freeze frame and stored data for fuel trims and sensor values
  • Scan live upstream O2/AFR sensor (Bank 1 Sensor 1) voltage or AFR trace
  • Check for additional DTCs (fuel trims, injector, MAP/MAF, fuel pressure, leaks)
  • Inspect sensor connector for corrosion, damage, or moisture
  • Visually inspect wiring harness for chafing, pinches or breaks
  • Perform smoke test or visual check for vacuum/exhaust leaks upstream of sensor

Signal parameters

  • Typical narrowband upstream O2 voltage: ~0.1–0.9 V (switching rapidly around 0.45 V)
  • Heater circuit: resistance typically low ohms (varies by sensor, often ~2–10 Ω) — consult vehicle spec
  • Sensor should switch rich/lean quickly at idle; slow or fixed readings indicate fault
  • Wideband/AFR sensors (if fitted) use different signal ranges — consult OEM spec for voltage/current/serial data

Diagnostic algorithm

  1. Connect a full-function OBD-II scanner and record freeze frame, stored codes and live data for Bank 1 Sensor 1 and fuel trims
  2. Confirm P1188 is current and note accompanying codes that narrow cause (fuel trims, injector, MAF, MAP, fuel pressure)
  3. With engine warm at idle, observe Bank 1 Sensor 1 waveform or AFR: a healthy narrowband sensor should switch regularly; wideband should follow commanded AFR
  4. Inspect sensor connector and wiring. Wiggle test harness while monitoring live data for intermittent changes
  5. Measure heater circuit: with connector disconnected measure resistance between heater pins and to ground for shorts; with ignition on measure heater supply voltage (consult wiring diagram)
  6. Check continuity between sensor pins and ECU connector; repair any opens/shorts
  7. Perform smoke/leak test of intake/exhaust for leaks upstream of the sensor and correct leaks found
  8. Verify fuel pressure and injector operation to ensure proper fueling; repair fuel-system faults
  9. If wiring and fuel system are good and sensor signals out of spec, replace Bank 1 Sensor 1 with OEM-equivalent and clear codes
  10. After repair, erase codes and perform road test / monitor live data to confirm normal sensor switching and normalized fuel trims

Likely causes

  • Failed or degraded Bank 1 Sensor 1
  • Open/short or intermittent wiring/connector to the sensor
  • Heater element open or no power to heater circuit
  • Vacuum/exhaust leak upstream of the sensor causing incorrect readings
  • Low/high fuel pressure or injector fault affecting AFR

Fault status

⚠️ Status
Fuel control fault detected on Bank 1 Sensor 1 — upstream oxygen/AFR sensor signal or heater circuit out of specification, affecting closed-loop fuel control.
🟡 Repair difficulty: Medium
⏱️ Diagnostic time: 1-2 hours

Similar codes

P0130 P0131 P0132 P0133 P0134 P0135
917

Browse 917 CHEVROLET manuals: repair procedures, diagnostics, wiring diagrams, component locations, service data and Labor Times by year, model and trim.

CHEVROLET

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Code

P1188

CHRYSLER P — Powertrain

EOT Sensor Circuit High Voltage

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

Causes

  • Faulty Bank 1 Sensor 1 (upstream O2/AFR sensor)
  • Damaged wiring or poor connector contact to the sensor
  • Heater circuit failure in the sensor
  • Exhaust leaks upstream of the sensor (false air)
  • Fuel pressure or injector problems causing out-of-range AFR
  • Contaminated sensor (oil, coolant, silicone)

Symptoms

  • Check Engine Light (MIL) on
  • Poor idle quality or rough running
  • Elevated or unstable fuel trims (long or short term)
  • Reduced fuel economy
  • Hesitation, stumble or reduced drivability under load
  • Possible hard starting or stalling

What to check

  • Read freeze frame and stored data for fuel trims and sensor values
  • Scan live upstream O2/AFR sensor (Bank 1 Sensor 1) voltage or AFR trace
  • Check for additional DTCs (fuel trims, injector, MAP/MAF, fuel pressure, leaks)
  • Inspect sensor connector for corrosion, damage, or moisture
  • Visually inspect wiring harness for chafing, pinches or breaks
  • Perform smoke test or visual check for vacuum/exhaust leaks upstream of sensor

Signal parameters

  • Typical narrowband upstream O2 voltage: ~0.1–0.9 V (switching rapidly around 0.45 V)
  • Heater circuit: resistance typically low ohms (varies by sensor, often ~2–10 Ω) — consult vehicle spec
  • Sensor should switch rich/lean quickly at idle; slow or fixed readings indicate fault
  • Wideband/AFR sensors (if fitted) use different signal ranges — consult OEM spec for voltage/current/serial data

Diagnostic algorithm

  1. Connect a full-function OBD-II scanner and record freeze frame, stored codes and live data for Bank 1 Sensor 1 and fuel trims
  2. Confirm P1188 is current and note accompanying codes that narrow cause (fuel trims, injector, MAF, MAP, fuel pressure)
  3. With engine warm at idle, observe Bank 1 Sensor 1 waveform or AFR: a healthy narrowband sensor should switch regularly; wideband should follow commanded AFR
  4. Inspect sensor connector and wiring. Wiggle test harness while monitoring live data for intermittent changes
  5. Measure heater circuit: with connector disconnected measure resistance between heater pins and to ground for shorts; with ignition on measure heater supply voltage (consult wiring diagram)
  6. Check continuity between sensor pins and ECU connector; repair any opens/shorts
  7. Perform smoke/leak test of intake/exhaust for leaks upstream of the sensor and correct leaks found
  8. Verify fuel pressure and injector operation to ensure proper fueling; repair fuel-system faults
  9. If wiring and fuel system are good and sensor signals out of spec, replace Bank 1 Sensor 1 with OEM-equivalent and clear codes
  10. After repair, erase codes and perform road test / monitor live data to confirm normal sensor switching and normalized fuel trims

Likely causes

  • Failed or degraded Bank 1 Sensor 1
  • Open/short or intermittent wiring/connector to the sensor
  • Heater element open or no power to heater circuit
  • Vacuum/exhaust leak upstream of the sensor causing incorrect readings
  • Low/high fuel pressure or injector fault affecting AFR

Fault status

⚠️ Status
Fuel control fault detected on Bank 1 Sensor 1 — upstream oxygen/AFR sensor signal or heater circuit out of specification, affecting closed-loop fuel control.
🟡 Repair difficulty: Medium
⏱️ Diagnostic time: 1-2 hours

Similar codes

P0130 P0131 P0132 P0133 P0134 P0135
193

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

CHRYSLER

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+100 karma for a short comment :)
Keep it short and practical. Up to 500 characters.
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Code

P1188

CITROEN P — Powertrain

Multifunction double relay control malfunction

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

Causes

  • Faulty Bank 1 Sensor 1 (upstream O2/AFR sensor)
  • Damaged wiring or poor connector contact to the sensor
  • Heater circuit failure in the sensor
  • Exhaust leaks upstream of the sensor (false air)
  • Fuel pressure or injector problems causing out-of-range AFR
  • Contaminated sensor (oil, coolant, silicone)

Symptoms

  • Check Engine Light (MIL) on
  • Poor idle quality or rough running
  • Elevated or unstable fuel trims (long or short term)
  • Reduced fuel economy
  • Hesitation, stumble or reduced drivability under load
  • Possible hard starting or stalling

What to check

  • Read freeze frame and stored data for fuel trims and sensor values
  • Scan live upstream O2/AFR sensor (Bank 1 Sensor 1) voltage or AFR trace
  • Check for additional DTCs (fuel trims, injector, MAP/MAF, fuel pressure, leaks)
  • Inspect sensor connector for corrosion, damage, or moisture
  • Visually inspect wiring harness for chafing, pinches or breaks
  • Perform smoke test or visual check for vacuum/exhaust leaks upstream of sensor

Signal parameters

  • Typical narrowband upstream O2 voltage: ~0.1–0.9 V (switching rapidly around 0.45 V)
  • Heater circuit: resistance typically low ohms (varies by sensor, often ~2–10 Ω) — consult vehicle spec
  • Sensor should switch rich/lean quickly at idle; slow or fixed readings indicate fault
  • Wideband/AFR sensors (if fitted) use different signal ranges — consult OEM spec for voltage/current/serial data

Diagnostic algorithm

  1. Connect a full-function OBD-II scanner and record freeze frame, stored codes and live data for Bank 1 Sensor 1 and fuel trims
  2. Confirm P1188 is current and note accompanying codes that narrow cause (fuel trims, injector, MAF, MAP, fuel pressure)
  3. With engine warm at idle, observe Bank 1 Sensor 1 waveform or AFR: a healthy narrowband sensor should switch regularly; wideband should follow commanded AFR
  4. Inspect sensor connector and wiring. Wiggle test harness while monitoring live data for intermittent changes
  5. Measure heater circuit: with connector disconnected measure resistance between heater pins and to ground for shorts; with ignition on measure heater supply voltage (consult wiring diagram)
  6. Check continuity between sensor pins and ECU connector; repair any opens/shorts
  7. Perform smoke/leak test of intake/exhaust for leaks upstream of the sensor and correct leaks found
  8. Verify fuel pressure and injector operation to ensure proper fueling; repair fuel-system faults
  9. If wiring and fuel system are good and sensor signals out of spec, replace Bank 1 Sensor 1 with OEM-equivalent and clear codes
  10. After repair, erase codes and perform road test / monitor live data to confirm normal sensor switching and normalized fuel trims

Likely causes

  • Failed or degraded Bank 1 Sensor 1
  • Open/short or intermittent wiring/connector to the sensor
  • Heater element open or no power to heater circuit
  • Vacuum/exhaust leak upstream of the sensor causing incorrect readings
  • Low/high fuel pressure or injector fault affecting AFR

Fault status

⚠️ Status
Fuel control fault detected on Bank 1 Sensor 1 — upstream oxygen/AFR sensor signal or heater circuit out of specification, affecting closed-loop fuel control.
🟡 Repair difficulty: Medium
⏱️ Diagnostic time: 1-2 hours

Similar codes

P0130 P0131 P0132 P0133 P0134 P0135
Your experience will help others
+100 karma for a short comment :)
Keep it short and practical. Up to 500 characters.
Send to email
Code

P1188

DS P — Powertrain

Multifunction double relay control malfunction

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

Causes

  • Faulty Bank 1 Sensor 1 (upstream O2/AFR sensor)
  • Damaged wiring or poor connector contact to the sensor
  • Heater circuit failure in the sensor
  • Exhaust leaks upstream of the sensor (false air)
  • Fuel pressure or injector problems causing out-of-range AFR
  • Contaminated sensor (oil, coolant, silicone)

Symptoms

  • Check Engine Light (MIL) on
  • Poor idle quality or rough running
  • Elevated or unstable fuel trims (long or short term)
  • Reduced fuel economy
  • Hesitation, stumble or reduced drivability under load
  • Possible hard starting or stalling

What to check

  • Read freeze frame and stored data for fuel trims and sensor values
  • Scan live upstream O2/AFR sensor (Bank 1 Sensor 1) voltage or AFR trace
  • Check for additional DTCs (fuel trims, injector, MAP/MAF, fuel pressure, leaks)
  • Inspect sensor connector for corrosion, damage, or moisture
  • Visually inspect wiring harness for chafing, pinches or breaks
  • Perform smoke test or visual check for vacuum/exhaust leaks upstream of sensor

Signal parameters

  • Typical narrowband upstream O2 voltage: ~0.1–0.9 V (switching rapidly around 0.45 V)
  • Heater circuit: resistance typically low ohms (varies by sensor, often ~2–10 Ω) — consult vehicle spec
  • Sensor should switch rich/lean quickly at idle; slow or fixed readings indicate fault
  • Wideband/AFR sensors (if fitted) use different signal ranges — consult OEM spec for voltage/current/serial data

Diagnostic algorithm

  1. Connect a full-function OBD-II scanner and record freeze frame, stored codes and live data for Bank 1 Sensor 1 and fuel trims
  2. Confirm P1188 is current and note accompanying codes that narrow cause (fuel trims, injector, MAF, MAP, fuel pressure)
  3. With engine warm at idle, observe Bank 1 Sensor 1 waveform or AFR: a healthy narrowband sensor should switch regularly; wideband should follow commanded AFR
  4. Inspect sensor connector and wiring. Wiggle test harness while monitoring live data for intermittent changes
  5. Measure heater circuit: with connector disconnected measure resistance between heater pins and to ground for shorts; with ignition on measure heater supply voltage (consult wiring diagram)
  6. Check continuity between sensor pins and ECU connector; repair any opens/shorts
  7. Perform smoke/leak test of intake/exhaust for leaks upstream of the sensor and correct leaks found
  8. Verify fuel pressure and injector operation to ensure proper fueling; repair fuel-system faults
  9. If wiring and fuel system are good and sensor signals out of spec, replace Bank 1 Sensor 1 with OEM-equivalent and clear codes
  10. After repair, erase codes and perform road test / monitor live data to confirm normal sensor switching and normalized fuel trims

Likely causes

  • Failed or degraded Bank 1 Sensor 1
  • Open/short or intermittent wiring/connector to the sensor
  • Heater element open or no power to heater circuit
  • Vacuum/exhaust leak upstream of the sensor causing incorrect readings
  • Low/high fuel pressure or injector fault affecting AFR

Fault status

⚠️ Status
Fuel control fault detected on Bank 1 Sensor 1 — upstream oxygen/AFR sensor signal or heater circuit out of specification, affecting closed-loop fuel control.
🟡 Repair difficulty: Medium
⏱️ Diagnostic time: 1-2 hours

Similar codes

P0130 P0131 P0132 P0133 P0134 P0135
Your experience will help others
+100 karma for a short comment :)
Keep it short and practical. Up to 500 characters.
Send to email
Code

P1188

FORD P — Powertrain

Calibration Memory Fault

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

Causes

  • Faulty Bank 1 Sensor 1 (upstream O2/AFR sensor)
  • Damaged wiring or poor connector contact to the sensor
  • Heater circuit failure in the sensor
  • Exhaust leaks upstream of the sensor (false air)
  • Fuel pressure or injector problems causing out-of-range AFR
  • Contaminated sensor (oil, coolant, silicone)

Symptoms

  • Check Engine Light (MIL) on
  • Poor idle quality or rough running
  • Elevated or unstable fuel trims (long or short term)
  • Reduced fuel economy
  • Hesitation, stumble or reduced drivability under load
  • Possible hard starting or stalling

What to check

  • Read freeze frame and stored data for fuel trims and sensor values
  • Scan live upstream O2/AFR sensor (Bank 1 Sensor 1) voltage or AFR trace
  • Check for additional DTCs (fuel trims, injector, MAP/MAF, fuel pressure, leaks)
  • Inspect sensor connector for corrosion, damage, or moisture
  • Visually inspect wiring harness for chafing, pinches or breaks
  • Perform smoke test or visual check for vacuum/exhaust leaks upstream of sensor

Signal parameters

  • Typical narrowband upstream O2 voltage: ~0.1–0.9 V (switching rapidly around 0.45 V)
  • Heater circuit: resistance typically low ohms (varies by sensor, often ~2–10 Ω) — consult vehicle spec
  • Sensor should switch rich/lean quickly at idle; slow or fixed readings indicate fault
  • Wideband/AFR sensors (if fitted) use different signal ranges — consult OEM spec for voltage/current/serial data

Diagnostic algorithm

  1. Connect a full-function OBD-II scanner and record freeze frame, stored codes and live data for Bank 1 Sensor 1 and fuel trims
  2. Confirm P1188 is current and note accompanying codes that narrow cause (fuel trims, injector, MAF, MAP, fuel pressure)
  3. With engine warm at idle, observe Bank 1 Sensor 1 waveform or AFR: a healthy narrowband sensor should switch regularly; wideband should follow commanded AFR
  4. Inspect sensor connector and wiring. Wiggle test harness while monitoring live data for intermittent changes
  5. Measure heater circuit: with connector disconnected measure resistance between heater pins and to ground for shorts; with ignition on measure heater supply voltage (consult wiring diagram)
  6. Check continuity between sensor pins and ECU connector; repair any opens/shorts
  7. Perform smoke/leak test of intake/exhaust for leaks upstream of the sensor and correct leaks found
  8. Verify fuel pressure and injector operation to ensure proper fueling; repair fuel-system faults
  9. If wiring and fuel system are good and sensor signals out of spec, replace Bank 1 Sensor 1 with OEM-equivalent and clear codes
  10. After repair, erase codes and perform road test / monitor live data to confirm normal sensor switching and normalized fuel trims

Likely causes

  • Failed or degraded Bank 1 Sensor 1
  • Open/short or intermittent wiring/connector to the sensor
  • Heater element open or no power to heater circuit
  • Vacuum/exhaust leak upstream of the sensor causing incorrect readings
  • Low/high fuel pressure or injector fault affecting AFR

Fault status

⚠️ Status
Fuel control fault detected on Bank 1 Sensor 1 — upstream oxygen/AFR sensor signal or heater circuit out of specification, affecting closed-loop fuel control.
🟡 Repair difficulty: Medium
⏱️ Diagnostic time: 1-2 hours

Similar codes

P0130 P0131 P0132 P0133 P0134 P0135
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Code

P1188

GM P — Powertrain

EOT Sensor Circuit High Voltage

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

Causes

  • Faulty Bank 1 Sensor 1 (upstream O2/AFR sensor)
  • Damaged wiring or poor connector contact to the sensor
  • Heater circuit failure in the sensor
  • Exhaust leaks upstream of the sensor (false air)
  • Fuel pressure or injector problems causing out-of-range AFR
  • Contaminated sensor (oil, coolant, silicone)

Symptoms

  • Check Engine Light (MIL) on
  • Poor idle quality or rough running
  • Elevated or unstable fuel trims (long or short term)
  • Reduced fuel economy
  • Hesitation, stumble or reduced drivability under load
  • Possible hard starting or stalling

What to check

  • Read freeze frame and stored data for fuel trims and sensor values
  • Scan live upstream O2/AFR sensor (Bank 1 Sensor 1) voltage or AFR trace
  • Check for additional DTCs (fuel trims, injector, MAP/MAF, fuel pressure, leaks)
  • Inspect sensor connector for corrosion, damage, or moisture
  • Visually inspect wiring harness for chafing, pinches or breaks
  • Perform smoke test or visual check for vacuum/exhaust leaks upstream of sensor

Signal parameters

  • Typical narrowband upstream O2 voltage: ~0.1–0.9 V (switching rapidly around 0.45 V)
  • Heater circuit: resistance typically low ohms (varies by sensor, often ~2–10 Ω) — consult vehicle spec
  • Sensor should switch rich/lean quickly at idle; slow or fixed readings indicate fault
  • Wideband/AFR sensors (if fitted) use different signal ranges — consult OEM spec for voltage/current/serial data

Diagnostic algorithm

  1. Connect a full-function OBD-II scanner and record freeze frame, stored codes and live data for Bank 1 Sensor 1 and fuel trims
  2. Confirm P1188 is current and note accompanying codes that narrow cause (fuel trims, injector, MAF, MAP, fuel pressure)
  3. With engine warm at idle, observe Bank 1 Sensor 1 waveform or AFR: a healthy narrowband sensor should switch regularly; wideband should follow commanded AFR
  4. Inspect sensor connector and wiring. Wiggle test harness while monitoring live data for intermittent changes
  5. Measure heater circuit: with connector disconnected measure resistance between heater pins and to ground for shorts; with ignition on measure heater supply voltage (consult wiring diagram)
  6. Check continuity between sensor pins and ECU connector; repair any opens/shorts
  7. Perform smoke/leak test of intake/exhaust for leaks upstream of the sensor and correct leaks found
  8. Verify fuel pressure and injector operation to ensure proper fueling; repair fuel-system faults
  9. If wiring and fuel system are good and sensor signals out of spec, replace Bank 1 Sensor 1 with OEM-equivalent and clear codes
  10. After repair, erase codes and perform road test / monitor live data to confirm normal sensor switching and normalized fuel trims

Likely causes

  • Failed or degraded Bank 1 Sensor 1
  • Open/short or intermittent wiring/connector to the sensor
  • Heater element open or no power to heater circuit
  • Vacuum/exhaust leak upstream of the sensor causing incorrect readings
  • Low/high fuel pressure or injector fault affecting AFR

Fault status

⚠️ Status
Fuel control fault detected on Bank 1 Sensor 1 — upstream oxygen/AFR sensor signal or heater circuit out of specification, affecting closed-loop fuel control.
🟡 Repair difficulty: Medium
⏱️ Diagnostic time: 1-2 hours

Similar codes

P0130 P0131 P0132 P0133 P0134 P0135
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Code

P1188

GMC P — Powertrain

EOT Sensor Circuit High Voltage

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

Causes

  • Faulty Bank 1 Sensor 1 (upstream O2/AFR sensor)
  • Damaged wiring or poor connector contact to the sensor
  • Heater circuit failure in the sensor
  • Exhaust leaks upstream of the sensor (false air)
  • Fuel pressure or injector problems causing out-of-range AFR
  • Contaminated sensor (oil, coolant, silicone)

Symptoms

  • Check Engine Light (MIL) on
  • Poor idle quality or rough running
  • Elevated or unstable fuel trims (long or short term)
  • Reduced fuel economy
  • Hesitation, stumble or reduced drivability under load
  • Possible hard starting or stalling

What to check

  • Read freeze frame and stored data for fuel trims and sensor values
  • Scan live upstream O2/AFR sensor (Bank 1 Sensor 1) voltage or AFR trace
  • Check for additional DTCs (fuel trims, injector, MAP/MAF, fuel pressure, leaks)
  • Inspect sensor connector for corrosion, damage, or moisture
  • Visually inspect wiring harness for chafing, pinches or breaks
  • Perform smoke test or visual check for vacuum/exhaust leaks upstream of sensor

Signal parameters

  • Typical narrowband upstream O2 voltage: ~0.1–0.9 V (switching rapidly around 0.45 V)
  • Heater circuit: resistance typically low ohms (varies by sensor, often ~2–10 Ω) — consult vehicle spec
  • Sensor should switch rich/lean quickly at idle; slow or fixed readings indicate fault
  • Wideband/AFR sensors (if fitted) use different signal ranges — consult OEM spec for voltage/current/serial data

Diagnostic algorithm

  1. Connect a full-function OBD-II scanner and record freeze frame, stored codes and live data for Bank 1 Sensor 1 and fuel trims
  2. Confirm P1188 is current and note accompanying codes that narrow cause (fuel trims, injector, MAF, MAP, fuel pressure)
  3. With engine warm at idle, observe Bank 1 Sensor 1 waveform or AFR: a healthy narrowband sensor should switch regularly; wideband should follow commanded AFR
  4. Inspect sensor connector and wiring. Wiggle test harness while monitoring live data for intermittent changes
  5. Measure heater circuit: with connector disconnected measure resistance between heater pins and to ground for shorts; with ignition on measure heater supply voltage (consult wiring diagram)
  6. Check continuity between sensor pins and ECU connector; repair any opens/shorts
  7. Perform smoke/leak test of intake/exhaust for leaks upstream of the sensor and correct leaks found
  8. Verify fuel pressure and injector operation to ensure proper fueling; repair fuel-system faults
  9. If wiring and fuel system are good and sensor signals out of spec, replace Bank 1 Sensor 1 with OEM-equivalent and clear codes
  10. After repair, erase codes and perform road test / monitor live data to confirm normal sensor switching and normalized fuel trims

Likely causes

  • Failed or degraded Bank 1 Sensor 1
  • Open/short or intermittent wiring/connector to the sensor
  • Heater element open or no power to heater circuit
  • Vacuum/exhaust leak upstream of the sensor causing incorrect readings
  • Low/high fuel pressure or injector fault affecting AFR

Fault status

⚠️ Status
Fuel control fault detected on Bank 1 Sensor 1 — upstream oxygen/AFR sensor signal or heater circuit out of specification, affecting closed-loop fuel control.
🟡 Repair difficulty: Medium
⏱️ Diagnostic time: 1-2 hours

Similar codes

P0130 P0131 P0132 P0133 P0134 P0135
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Code

P1188

HUMMER P — Powertrain

EOT Sensor Circuit High Voltage

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

Causes

  • Faulty Bank 1 Sensor 1 (upstream O2/AFR sensor)
  • Damaged wiring or poor connector contact to the sensor
  • Heater circuit failure in the sensor
  • Exhaust leaks upstream of the sensor (false air)
  • Fuel pressure or injector problems causing out-of-range AFR
  • Contaminated sensor (oil, coolant, silicone)

Symptoms

  • Check Engine Light (MIL) on
  • Poor idle quality or rough running
  • Elevated or unstable fuel trims (long or short term)
  • Reduced fuel economy
  • Hesitation, stumble or reduced drivability under load
  • Possible hard starting or stalling

What to check

  • Read freeze frame and stored data for fuel trims and sensor values
  • Scan live upstream O2/AFR sensor (Bank 1 Sensor 1) voltage or AFR trace
  • Check for additional DTCs (fuel trims, injector, MAP/MAF, fuel pressure, leaks)
  • Inspect sensor connector for corrosion, damage, or moisture
  • Visually inspect wiring harness for chafing, pinches or breaks
  • Perform smoke test or visual check for vacuum/exhaust leaks upstream of sensor

Signal parameters

  • Typical narrowband upstream O2 voltage: ~0.1–0.9 V (switching rapidly around 0.45 V)
  • Heater circuit: resistance typically low ohms (varies by sensor, often ~2–10 Ω) — consult vehicle spec
  • Sensor should switch rich/lean quickly at idle; slow or fixed readings indicate fault
  • Wideband/AFR sensors (if fitted) use different signal ranges — consult OEM spec for voltage/current/serial data

Diagnostic algorithm

  1. Connect a full-function OBD-II scanner and record freeze frame, stored codes and live data for Bank 1 Sensor 1 and fuel trims
  2. Confirm P1188 is current and note accompanying codes that narrow cause (fuel trims, injector, MAF, MAP, fuel pressure)
  3. With engine warm at idle, observe Bank 1 Sensor 1 waveform or AFR: a healthy narrowband sensor should switch regularly; wideband should follow commanded AFR
  4. Inspect sensor connector and wiring. Wiggle test harness while monitoring live data for intermittent changes
  5. Measure heater circuit: with connector disconnected measure resistance between heater pins and to ground for shorts; with ignition on measure heater supply voltage (consult wiring diagram)
  6. Check continuity between sensor pins and ECU connector; repair any opens/shorts
  7. Perform smoke/leak test of intake/exhaust for leaks upstream of the sensor and correct leaks found
  8. Verify fuel pressure and injector operation to ensure proper fueling; repair fuel-system faults
  9. If wiring and fuel system are good and sensor signals out of spec, replace Bank 1 Sensor 1 with OEM-equivalent and clear codes
  10. After repair, erase codes and perform road test / monitor live data to confirm normal sensor switching and normalized fuel trims

Likely causes

  • Failed or degraded Bank 1 Sensor 1
  • Open/short or intermittent wiring/connector to the sensor
  • Heater element open or no power to heater circuit
  • Vacuum/exhaust leak upstream of the sensor causing incorrect readings
  • Low/high fuel pressure or injector fault affecting AFR

Fault status

⚠️ Status
Fuel control fault detected on Bank 1 Sensor 1 — upstream oxygen/AFR sensor signal or heater circuit out of specification, affecting closed-loop fuel control.
🟡 Repair difficulty: Medium
⏱️ Diagnostic time: 1-2 hours

Similar codes

P0130 P0131 P0132 P0133 P0134 P0135
Repair manuals

Manual library for HUMMER

138

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Code

P1188

JAGUAR P — Powertrain

O2 Sensor Heater Circuit Resistance

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

Causes

  • Faulty Bank 1 Sensor 1 (upstream O2/AFR sensor)
  • Damaged wiring or poor connector contact to the sensor
  • Heater circuit failure in the sensor
  • Exhaust leaks upstream of the sensor (false air)
  • Fuel pressure or injector problems causing out-of-range AFR
  • Contaminated sensor (oil, coolant, silicone)

Symptoms

  • Check Engine Light (MIL) on
  • Poor idle quality or rough running
  • Elevated or unstable fuel trims (long or short term)
  • Reduced fuel economy
  • Hesitation, stumble or reduced drivability under load
  • Possible hard starting or stalling

What to check

  • Read freeze frame and stored data for fuel trims and sensor values
  • Scan live upstream O2/AFR sensor (Bank 1 Sensor 1) voltage or AFR trace
  • Check for additional DTCs (fuel trims, injector, MAP/MAF, fuel pressure, leaks)
  • Inspect sensor connector for corrosion, damage, or moisture
  • Visually inspect wiring harness for chafing, pinches or breaks
  • Perform smoke test or visual check for vacuum/exhaust leaks upstream of sensor

Signal parameters

  • Typical narrowband upstream O2 voltage: ~0.1–0.9 V (switching rapidly around 0.45 V)
  • Heater circuit: resistance typically low ohms (varies by sensor, often ~2–10 Ω) — consult vehicle spec
  • Sensor should switch rich/lean quickly at idle; slow or fixed readings indicate fault
  • Wideband/AFR sensors (if fitted) use different signal ranges — consult OEM spec for voltage/current/serial data

Diagnostic algorithm

  1. Connect a full-function OBD-II scanner and record freeze frame, stored codes and live data for Bank 1 Sensor 1 and fuel trims
  2. Confirm P1188 is current and note accompanying codes that narrow cause (fuel trims, injector, MAF, MAP, fuel pressure)
  3. With engine warm at idle, observe Bank 1 Sensor 1 waveform or AFR: a healthy narrowband sensor should switch regularly; wideband should follow commanded AFR
  4. Inspect sensor connector and wiring. Wiggle test harness while monitoring live data for intermittent changes
  5. Measure heater circuit: with connector disconnected measure resistance between heater pins and to ground for shorts; with ignition on measure heater supply voltage (consult wiring diagram)
  6. Check continuity between sensor pins and ECU connector; repair any opens/shorts
  7. Perform smoke/leak test of intake/exhaust for leaks upstream of the sensor and correct leaks found
  8. Verify fuel pressure and injector operation to ensure proper fueling; repair fuel-system faults
  9. If wiring and fuel system are good and sensor signals out of spec, replace Bank 1 Sensor 1 with OEM-equivalent and clear codes
  10. After repair, erase codes and perform road test / monitor live data to confirm normal sensor switching and normalized fuel trims

Likely causes

  • Failed or degraded Bank 1 Sensor 1
  • Open/short or intermittent wiring/connector to the sensor
  • Heater element open or no power to heater circuit
  • Vacuum/exhaust leak upstream of the sensor causing incorrect readings
  • Low/high fuel pressure or injector fault affecting AFR

Fault status

⚠️ Status
Fuel control fault detected on Bank 1 Sensor 1 — upstream oxygen/AFR sensor signal or heater circuit out of specification, affecting closed-loop fuel control.
🟡 Repair difficulty: Medium
⏱️ Diagnostic time: 1-2 hours

Similar codes

P0130 P0131 P0132 P0133 P0134 P0135
Your experience will help others
+100 karma for a short comment :)
Keep it short and practical. Up to 500 characters.
Send to email
Code

P1188

LAND ROVER P — Powertrain

Circuit heater resistance failure of the oxygen sensor heated (banks 1 and 2 sensor 1)

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

Causes

  • Faulty Bank 1 Sensor 1 (upstream O2/AFR sensor)
  • Damaged wiring or poor connector contact to the sensor
  • Heater circuit failure in the sensor
  • Exhaust leaks upstream of the sensor (false air)
  • Fuel pressure or injector problems causing out-of-range AFR
  • Contaminated sensor (oil, coolant, silicone)

Symptoms

  • Check Engine Light (MIL) on
  • Poor idle quality or rough running
  • Elevated or unstable fuel trims (long or short term)
  • Reduced fuel economy
  • Hesitation, stumble or reduced drivability under load
  • Possible hard starting or stalling

What to check

  • Read freeze frame and stored data for fuel trims and sensor values
  • Scan live upstream O2/AFR sensor (Bank 1 Sensor 1) voltage or AFR trace
  • Check for additional DTCs (fuel trims, injector, MAP/MAF, fuel pressure, leaks)
  • Inspect sensor connector for corrosion, damage, or moisture
  • Visually inspect wiring harness for chafing, pinches or breaks
  • Perform smoke test or visual check for vacuum/exhaust leaks upstream of sensor

Signal parameters

  • Typical narrowband upstream O2 voltage: ~0.1–0.9 V (switching rapidly around 0.45 V)
  • Heater circuit: resistance typically low ohms (varies by sensor, often ~2–10 Ω) — consult vehicle spec
  • Sensor should switch rich/lean quickly at idle; slow or fixed readings indicate fault
  • Wideband/AFR sensors (if fitted) use different signal ranges — consult OEM spec for voltage/current/serial data

Diagnostic algorithm

  1. Connect a full-function OBD-II scanner and record freeze frame, stored codes and live data for Bank 1 Sensor 1 and fuel trims
  2. Confirm P1188 is current and note accompanying codes that narrow cause (fuel trims, injector, MAF, MAP, fuel pressure)
  3. With engine warm at idle, observe Bank 1 Sensor 1 waveform or AFR: a healthy narrowband sensor should switch regularly; wideband should follow commanded AFR
  4. Inspect sensor connector and wiring. Wiggle test harness while monitoring live data for intermittent changes
  5. Measure heater circuit: with connector disconnected measure resistance between heater pins and to ground for shorts; with ignition on measure heater supply voltage (consult wiring diagram)
  6. Check continuity between sensor pins and ECU connector; repair any opens/shorts
  7. Perform smoke/leak test of intake/exhaust for leaks upstream of the sensor and correct leaks found
  8. Verify fuel pressure and injector operation to ensure proper fueling; repair fuel-system faults
  9. If wiring and fuel system are good and sensor signals out of spec, replace Bank 1 Sensor 1 with OEM-equivalent and clear codes
  10. After repair, erase codes and perform road test / monitor live data to confirm normal sensor switching and normalized fuel trims

Likely causes

  • Failed or degraded Bank 1 Sensor 1
  • Open/short or intermittent wiring/connector to the sensor
  • Heater element open or no power to heater circuit
  • Vacuum/exhaust leak upstream of the sensor causing incorrect readings
  • Low/high fuel pressure or injector fault affecting AFR

Fault status

⚠️ Status
Fuel control fault detected on Bank 1 Sensor 1 — upstream oxygen/AFR sensor signal or heater circuit out of specification, affecting closed-loop fuel control.
🟡 Repair difficulty: Medium
⏱️ Diagnostic time: 1-2 hours

Similar codes

P0130 P0131 P0132 P0133 P0134 P0135
413

Browse 413 LAND ROVER manuals: repair procedures, diagnostics, wiring diagrams, component locations, service data and Labor Times by year, model and trim.

LAND ROVER

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Code

P1188

LINCOLN P — Powertrain

Calibration Memory Fault

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

Causes

  • Faulty Bank 1 Sensor 1 (upstream O2/AFR sensor)
  • Damaged wiring or poor connector contact to the sensor
  • Heater circuit failure in the sensor
  • Exhaust leaks upstream of the sensor (false air)
  • Fuel pressure or injector problems causing out-of-range AFR
  • Contaminated sensor (oil, coolant, silicone)

Symptoms

  • Check Engine Light (MIL) on
  • Poor idle quality or rough running
  • Elevated or unstable fuel trims (long or short term)
  • Reduced fuel economy
  • Hesitation, stumble or reduced drivability under load
  • Possible hard starting or stalling

What to check

  • Read freeze frame and stored data for fuel trims and sensor values
  • Scan live upstream O2/AFR sensor (Bank 1 Sensor 1) voltage or AFR trace
  • Check for additional DTCs (fuel trims, injector, MAP/MAF, fuel pressure, leaks)
  • Inspect sensor connector for corrosion, damage, or moisture
  • Visually inspect wiring harness for chafing, pinches or breaks
  • Perform smoke test or visual check for vacuum/exhaust leaks upstream of sensor

Signal parameters

  • Typical narrowband upstream O2 voltage: ~0.1–0.9 V (switching rapidly around 0.45 V)
  • Heater circuit: resistance typically low ohms (varies by sensor, often ~2–10 Ω) — consult vehicle spec
  • Sensor should switch rich/lean quickly at idle; slow or fixed readings indicate fault
  • Wideband/AFR sensors (if fitted) use different signal ranges — consult OEM spec for voltage/current/serial data

Diagnostic algorithm

  1. Connect a full-function OBD-II scanner and record freeze frame, stored codes and live data for Bank 1 Sensor 1 and fuel trims
  2. Confirm P1188 is current and note accompanying codes that narrow cause (fuel trims, injector, MAF, MAP, fuel pressure)
  3. With engine warm at idle, observe Bank 1 Sensor 1 waveform or AFR: a healthy narrowband sensor should switch regularly; wideband should follow commanded AFR
  4. Inspect sensor connector and wiring. Wiggle test harness while monitoring live data for intermittent changes
  5. Measure heater circuit: with connector disconnected measure resistance between heater pins and to ground for shorts; with ignition on measure heater supply voltage (consult wiring diagram)
  6. Check continuity between sensor pins and ECU connector; repair any opens/shorts
  7. Perform smoke/leak test of intake/exhaust for leaks upstream of the sensor and correct leaks found
  8. Verify fuel pressure and injector operation to ensure proper fueling; repair fuel-system faults
  9. If wiring and fuel system are good and sensor signals out of spec, replace Bank 1 Sensor 1 with OEM-equivalent and clear codes
  10. After repair, erase codes and perform road test / monitor live data to confirm normal sensor switching and normalized fuel trims

Likely causes

  • Failed or degraded Bank 1 Sensor 1
  • Open/short or intermittent wiring/connector to the sensor
  • Heater element open or no power to heater circuit
  • Vacuum/exhaust leak upstream of the sensor causing incorrect readings
  • Low/high fuel pressure or injector fault affecting AFR

Fault status

⚠️ Status
Fuel control fault detected on Bank 1 Sensor 1 — upstream oxygen/AFR sensor signal or heater circuit out of specification, affecting closed-loop fuel control.
🟡 Repair difficulty: Medium
⏱️ Diagnostic time: 1-2 hours

Similar codes

P0130 P0131 P0132 P0133 P0134 P0135
166

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

LINCOLN

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Code

P1188

MERCURY P — Powertrain

Calibration Memory Fault

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

Causes

  • Faulty Bank 1 Sensor 1 (upstream O2/AFR sensor)
  • Damaged wiring or poor connector contact to the sensor
  • Heater circuit failure in the sensor
  • Exhaust leaks upstream of the sensor (false air)
  • Fuel pressure or injector problems causing out-of-range AFR
  • Contaminated sensor (oil, coolant, silicone)

Symptoms

  • Check Engine Light (MIL) on
  • Poor idle quality or rough running
  • Elevated or unstable fuel trims (long or short term)
  • Reduced fuel economy
  • Hesitation, stumble or reduced drivability under load
  • Possible hard starting or stalling

What to check

  • Read freeze frame and stored data for fuel trims and sensor values
  • Scan live upstream O2/AFR sensor (Bank 1 Sensor 1) voltage or AFR trace
  • Check for additional DTCs (fuel trims, injector, MAP/MAF, fuel pressure, leaks)
  • Inspect sensor connector for corrosion, damage, or moisture
  • Visually inspect wiring harness for chafing, pinches or breaks
  • Perform smoke test or visual check for vacuum/exhaust leaks upstream of sensor

Signal parameters

  • Typical narrowband upstream O2 voltage: ~0.1–0.9 V (switching rapidly around 0.45 V)
  • Heater circuit: resistance typically low ohms (varies by sensor, often ~2–10 Ω) — consult vehicle spec
  • Sensor should switch rich/lean quickly at idle; slow or fixed readings indicate fault
  • Wideband/AFR sensors (if fitted) use different signal ranges — consult OEM spec for voltage/current/serial data

Diagnostic algorithm

  1. Connect a full-function OBD-II scanner and record freeze frame, stored codes and live data for Bank 1 Sensor 1 and fuel trims
  2. Confirm P1188 is current and note accompanying codes that narrow cause (fuel trims, injector, MAF, MAP, fuel pressure)
  3. With engine warm at idle, observe Bank 1 Sensor 1 waveform or AFR: a healthy narrowband sensor should switch regularly; wideband should follow commanded AFR
  4. Inspect sensor connector and wiring. Wiggle test harness while monitoring live data for intermittent changes
  5. Measure heater circuit: with connector disconnected measure resistance between heater pins and to ground for shorts; with ignition on measure heater supply voltage (consult wiring diagram)
  6. Check continuity between sensor pins and ECU connector; repair any opens/shorts
  7. Perform smoke/leak test of intake/exhaust for leaks upstream of the sensor and correct leaks found
  8. Verify fuel pressure and injector operation to ensure proper fueling; repair fuel-system faults
  9. If wiring and fuel system are good and sensor signals out of spec, replace Bank 1 Sensor 1 with OEM-equivalent and clear codes
  10. After repair, erase codes and perform road test / monitor live data to confirm normal sensor switching and normalized fuel trims

Likely causes

  • Failed or degraded Bank 1 Sensor 1
  • Open/short or intermittent wiring/connector to the sensor
  • Heater element open or no power to heater circuit
  • Vacuum/exhaust leak upstream of the sensor causing incorrect readings
  • Low/high fuel pressure or injector fault affecting AFR

Fault status

⚠️ Status
Fuel control fault detected on Bank 1 Sensor 1 — upstream oxygen/AFR sensor signal or heater circuit out of specification, affecting closed-loop fuel control.
🟡 Repair difficulty: Medium
⏱️ Diagnostic time: 1-2 hours

Similar codes

P0130 P0131 P0132 P0133 P0134 P0135
296

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

MERCURY

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Code

P1188

OLDSMOBILE P — Powertrain

EOT Sensor Circuit High Voltage

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

Causes

  • Faulty Bank 1 Sensor 1 (upstream O2/AFR sensor)
  • Damaged wiring or poor connector contact to the sensor
  • Heater circuit failure in the sensor
  • Exhaust leaks upstream of the sensor (false air)
  • Fuel pressure or injector problems causing out-of-range AFR
  • Contaminated sensor (oil, coolant, silicone)

Symptoms

  • Check Engine Light (MIL) on
  • Poor idle quality or rough running
  • Elevated or unstable fuel trims (long or short term)
  • Reduced fuel economy
  • Hesitation, stumble or reduced drivability under load
  • Possible hard starting or stalling

What to check

  • Read freeze frame and stored data for fuel trims and sensor values
  • Scan live upstream O2/AFR sensor (Bank 1 Sensor 1) voltage or AFR trace
  • Check for additional DTCs (fuel trims, injector, MAP/MAF, fuel pressure, leaks)
  • Inspect sensor connector for corrosion, damage, or moisture
  • Visually inspect wiring harness for chafing, pinches or breaks
  • Perform smoke test or visual check for vacuum/exhaust leaks upstream of sensor

Signal parameters

  • Typical narrowband upstream O2 voltage: ~0.1–0.9 V (switching rapidly around 0.45 V)
  • Heater circuit: resistance typically low ohms (varies by sensor, often ~2–10 Ω) — consult vehicle spec
  • Sensor should switch rich/lean quickly at idle; slow or fixed readings indicate fault
  • Wideband/AFR sensors (if fitted) use different signal ranges — consult OEM spec for voltage/current/serial data

Diagnostic algorithm

  1. Connect a full-function OBD-II scanner and record freeze frame, stored codes and live data for Bank 1 Sensor 1 and fuel trims
  2. Confirm P1188 is current and note accompanying codes that narrow cause (fuel trims, injector, MAF, MAP, fuel pressure)
  3. With engine warm at idle, observe Bank 1 Sensor 1 waveform or AFR: a healthy narrowband sensor should switch regularly; wideband should follow commanded AFR
  4. Inspect sensor connector and wiring. Wiggle test harness while monitoring live data for intermittent changes
  5. Measure heater circuit: with connector disconnected measure resistance between heater pins and to ground for shorts; with ignition on measure heater supply voltage (consult wiring diagram)
  6. Check continuity between sensor pins and ECU connector; repair any opens/shorts
  7. Perform smoke/leak test of intake/exhaust for leaks upstream of the sensor and correct leaks found
  8. Verify fuel pressure and injector operation to ensure proper fueling; repair fuel-system faults
  9. If wiring and fuel system are good and sensor signals out of spec, replace Bank 1 Sensor 1 with OEM-equivalent and clear codes
  10. After repair, erase codes and perform road test / monitor live data to confirm normal sensor switching and normalized fuel trims

Likely causes

  • Failed or degraded Bank 1 Sensor 1
  • Open/short or intermittent wiring/connector to the sensor
  • Heater element open or no power to heater circuit
  • Vacuum/exhaust leak upstream of the sensor causing incorrect readings
  • Low/high fuel pressure or injector fault affecting AFR

Fault status

⚠️ Status
Fuel control fault detected on Bank 1 Sensor 1 — upstream oxygen/AFR sensor signal or heater circuit out of specification, affecting closed-loop fuel control.
🟡 Repair difficulty: Medium
⏱️ Diagnostic time: 1-2 hours

Similar codes

P0130 P0131 P0132 P0133 P0134 P0135
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Code

P1188

Other P — Powertrain

Calibration Memory Fault

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

Causes

  • Faulty Bank 1 Sensor 1 (upstream O2/AFR sensor)
  • Damaged wiring or poor connector contact to the sensor
  • Heater circuit failure in the sensor
  • Exhaust leaks upstream of the sensor (false air)
  • Fuel pressure or injector problems causing out-of-range AFR
  • Contaminated sensor (oil, coolant, silicone)

Symptoms

  • Check Engine Light (MIL) on
  • Poor idle quality or rough running
  • Elevated or unstable fuel trims (long or short term)
  • Reduced fuel economy
  • Hesitation, stumble or reduced drivability under load
  • Possible hard starting or stalling

What to check

  • Read freeze frame and stored data for fuel trims and sensor values
  • Scan live upstream O2/AFR sensor (Bank 1 Sensor 1) voltage or AFR trace
  • Check for additional DTCs (fuel trims, injector, MAP/MAF, fuel pressure, leaks)
  • Inspect sensor connector for corrosion, damage, or moisture
  • Visually inspect wiring harness for chafing, pinches or breaks
  • Perform smoke test or visual check for vacuum/exhaust leaks upstream of sensor

Signal parameters

  • Typical narrowband upstream O2 voltage: ~0.1–0.9 V (switching rapidly around 0.45 V)
  • Heater circuit: resistance typically low ohms (varies by sensor, often ~2–10 Ω) — consult vehicle spec
  • Sensor should switch rich/lean quickly at idle; slow or fixed readings indicate fault
  • Wideband/AFR sensors (if fitted) use different signal ranges — consult OEM spec for voltage/current/serial data

Diagnostic algorithm

  1. Connect a full-function OBD-II scanner and record freeze frame, stored codes and live data for Bank 1 Sensor 1 and fuel trims
  2. Confirm P1188 is current and note accompanying codes that narrow cause (fuel trims, injector, MAF, MAP, fuel pressure)
  3. With engine warm at idle, observe Bank 1 Sensor 1 waveform or AFR: a healthy narrowband sensor should switch regularly; wideband should follow commanded AFR
  4. Inspect sensor connector and wiring. Wiggle test harness while monitoring live data for intermittent changes
  5. Measure heater circuit: with connector disconnected measure resistance between heater pins and to ground for shorts; with ignition on measure heater supply voltage (consult wiring diagram)
  6. Check continuity between sensor pins and ECU connector; repair any opens/shorts
  7. Perform smoke/leak test of intake/exhaust for leaks upstream of the sensor and correct leaks found
  8. Verify fuel pressure and injector operation to ensure proper fueling; repair fuel-system faults
  9. If wiring and fuel system are good and sensor signals out of spec, replace Bank 1 Sensor 1 with OEM-equivalent and clear codes
  10. After repair, erase codes and perform road test / monitor live data to confirm normal sensor switching and normalized fuel trims

Likely causes

  • Failed or degraded Bank 1 Sensor 1
  • Open/short or intermittent wiring/connector to the sensor
  • Heater element open or no power to heater circuit
  • Vacuum/exhaust leak upstream of the sensor causing incorrect readings
  • Low/high fuel pressure or injector fault affecting AFR

Fault status

⚠️ Status
Fuel control fault detected on Bank 1 Sensor 1 — upstream oxygen/AFR sensor signal or heater circuit out of specification, affecting closed-loop fuel control.
🟡 Repair difficulty: Medium
⏱️ Diagnostic time: 1-2 hours

Similar codes

P0130 P0131 P0132 P0133 P0134 P0135
10,773

The library contains 10,773 repair and diagnostic manuals. Choose a brand to open the full manual tree by year, model and trim.

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Code

P1188

PEUGEOT P — Powertrain

Multifunction double relay control malfunction

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

Causes

  • Faulty Bank 1 Sensor 1 (upstream O2/AFR sensor)
  • Damaged wiring or poor connector contact to the sensor
  • Heater circuit failure in the sensor
  • Exhaust leaks upstream of the sensor (false air)
  • Fuel pressure or injector problems causing out-of-range AFR
  • Contaminated sensor (oil, coolant, silicone)

Symptoms

  • Check Engine Light (MIL) on
  • Poor idle quality or rough running
  • Elevated or unstable fuel trims (long or short term)
  • Reduced fuel economy
  • Hesitation, stumble or reduced drivability under load
  • Possible hard starting or stalling

What to check

  • Read freeze frame and stored data for fuel trims and sensor values
  • Scan live upstream O2/AFR sensor (Bank 1 Sensor 1) voltage or AFR trace
  • Check for additional DTCs (fuel trims, injector, MAP/MAF, fuel pressure, leaks)
  • Inspect sensor connector for corrosion, damage, or moisture
  • Visually inspect wiring harness for chafing, pinches or breaks
  • Perform smoke test or visual check for vacuum/exhaust leaks upstream of sensor

Signal parameters

  • Typical narrowband upstream O2 voltage: ~0.1–0.9 V (switching rapidly around 0.45 V)
  • Heater circuit: resistance typically low ohms (varies by sensor, often ~2–10 Ω) — consult vehicle spec
  • Sensor should switch rich/lean quickly at idle; slow or fixed readings indicate fault
  • Wideband/AFR sensors (if fitted) use different signal ranges — consult OEM spec for voltage/current/serial data

Diagnostic algorithm

  1. Connect a full-function OBD-II scanner and record freeze frame, stored codes and live data for Bank 1 Sensor 1 and fuel trims
  2. Confirm P1188 is current and note accompanying codes that narrow cause (fuel trims, injector, MAF, MAP, fuel pressure)
  3. With engine warm at idle, observe Bank 1 Sensor 1 waveform or AFR: a healthy narrowband sensor should switch regularly; wideband should follow commanded AFR
  4. Inspect sensor connector and wiring. Wiggle test harness while monitoring live data for intermittent changes
  5. Measure heater circuit: with connector disconnected measure resistance between heater pins and to ground for shorts; with ignition on measure heater supply voltage (consult wiring diagram)
  6. Check continuity between sensor pins and ECU connector; repair any opens/shorts
  7. Perform smoke/leak test of intake/exhaust for leaks upstream of the sensor and correct leaks found
  8. Verify fuel pressure and injector operation to ensure proper fueling; repair fuel-system faults
  9. If wiring and fuel system are good and sensor signals out of spec, replace Bank 1 Sensor 1 with OEM-equivalent and clear codes
  10. After repair, erase codes and perform road test / monitor live data to confirm normal sensor switching and normalized fuel trims

Likely causes

  • Failed or degraded Bank 1 Sensor 1
  • Open/short or intermittent wiring/connector to the sensor
  • Heater element open or no power to heater circuit
  • Vacuum/exhaust leak upstream of the sensor causing incorrect readings
  • Low/high fuel pressure or injector fault affecting AFR

Fault status

⚠️ Status
Fuel control fault detected on Bank 1 Sensor 1 — upstream oxygen/AFR sensor signal or heater circuit out of specification, affecting closed-loop fuel control.
🟡 Repair difficulty: Medium
⏱️ Diagnostic time: 1-2 hours

Similar codes

P0130 P0131 P0132 P0133 P0134 P0135
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+100 karma for a short comment :)
Keep it short and practical. Up to 500 characters.
Send to email
Code

P1188

RAM P — Powertrain

Inlet Air Pressure Sensor Circuit Range/Performance

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

Causes

  • Faulty Bank 1 Sensor 1 (upstream O2/AFR sensor)
  • Damaged wiring or poor connector contact to the sensor
  • Heater circuit failure in the sensor
  • Exhaust leaks upstream of the sensor (false air)
  • Fuel pressure or injector problems causing out-of-range AFR
  • Contaminated sensor (oil, coolant, silicone)

Symptoms

  • Check Engine Light (MIL) on
  • Poor idle quality or rough running
  • Elevated or unstable fuel trims (long or short term)
  • Reduced fuel economy
  • Hesitation, stumble or reduced drivability under load
  • Possible hard starting or stalling

What to check

  • Read freeze frame and stored data for fuel trims and sensor values
  • Scan live upstream O2/AFR sensor (Bank 1 Sensor 1) voltage or AFR trace
  • Check for additional DTCs (fuel trims, injector, MAP/MAF, fuel pressure, leaks)
  • Inspect sensor connector for corrosion, damage, or moisture
  • Visually inspect wiring harness for chafing, pinches or breaks
  • Perform smoke test or visual check for vacuum/exhaust leaks upstream of sensor

Signal parameters

  • Typical narrowband upstream O2 voltage: ~0.1–0.9 V (switching rapidly around 0.45 V)
  • Heater circuit: resistance typically low ohms (varies by sensor, often ~2–10 Ω) — consult vehicle spec
  • Sensor should switch rich/lean quickly at idle; slow or fixed readings indicate fault
  • Wideband/AFR sensors (if fitted) use different signal ranges — consult OEM spec for voltage/current/serial data

Diagnostic algorithm

  1. Connect a full-function OBD-II scanner and record freeze frame, stored codes and live data for Bank 1 Sensor 1 and fuel trims
  2. Confirm P1188 is current and note accompanying codes that narrow cause (fuel trims, injector, MAF, MAP, fuel pressure)
  3. With engine warm at idle, observe Bank 1 Sensor 1 waveform or AFR: a healthy narrowband sensor should switch regularly; wideband should follow commanded AFR
  4. Inspect sensor connector and wiring. Wiggle test harness while monitoring live data for intermittent changes
  5. Measure heater circuit: with connector disconnected measure resistance between heater pins and to ground for shorts; with ignition on measure heater supply voltage (consult wiring diagram)
  6. Check continuity between sensor pins and ECU connector; repair any opens/shorts
  7. Perform smoke/leak test of intake/exhaust for leaks upstream of the sensor and correct leaks found
  8. Verify fuel pressure and injector operation to ensure proper fueling; repair fuel-system faults
  9. If wiring and fuel system are good and sensor signals out of spec, replace Bank 1 Sensor 1 with OEM-equivalent and clear codes
  10. After repair, erase codes and perform road test / monitor live data to confirm normal sensor switching and normalized fuel trims

Likely causes

  • Failed or degraded Bank 1 Sensor 1
  • Open/short or intermittent wiring/connector to the sensor
  • Heater element open or no power to heater circuit
  • Vacuum/exhaust leak upstream of the sensor causing incorrect readings
  • Low/high fuel pressure or injector fault affecting AFR

Fault status

⚠️ Status
Fuel control fault detected on Bank 1 Sensor 1 — upstream oxygen/AFR sensor signal or heater circuit out of specification, affecting closed-loop fuel control.
🟡 Repair difficulty: Medium
⏱️ Diagnostic time: 1-2 hours

Similar codes

P0130 P0131 P0132 P0133 P0134 P0135
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+100 karma for a short comment :)
Keep it short and practical. Up to 500 characters.
Send to email
Code

P1188

SATURN P — Powertrain

EOT Sensor Circuit High Voltage

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

Causes

  • Faulty Bank 1 Sensor 1 (upstream O2/AFR sensor)
  • Damaged wiring or poor connector contact to the sensor
  • Heater circuit failure in the sensor
  • Exhaust leaks upstream of the sensor (false air)
  • Fuel pressure or injector problems causing out-of-range AFR
  • Contaminated sensor (oil, coolant, silicone)

Symptoms

  • Check Engine Light (MIL) on
  • Poor idle quality or rough running
  • Elevated or unstable fuel trims (long or short term)
  • Reduced fuel economy
  • Hesitation, stumble or reduced drivability under load
  • Possible hard starting or stalling

What to check

  • Read freeze frame and stored data for fuel trims and sensor values
  • Scan live upstream O2/AFR sensor (Bank 1 Sensor 1) voltage or AFR trace
  • Check for additional DTCs (fuel trims, injector, MAP/MAF, fuel pressure, leaks)
  • Inspect sensor connector for corrosion, damage, or moisture
  • Visually inspect wiring harness for chafing, pinches or breaks
  • Perform smoke test or visual check for vacuum/exhaust leaks upstream of sensor

Signal parameters

  • Typical narrowband upstream O2 voltage: ~0.1–0.9 V (switching rapidly around 0.45 V)
  • Heater circuit: resistance typically low ohms (varies by sensor, often ~2–10 Ω) — consult vehicle spec
  • Sensor should switch rich/lean quickly at idle; slow or fixed readings indicate fault
  • Wideband/AFR sensors (if fitted) use different signal ranges — consult OEM spec for voltage/current/serial data

Diagnostic algorithm

  1. Connect a full-function OBD-II scanner and record freeze frame, stored codes and live data for Bank 1 Sensor 1 and fuel trims
  2. Confirm P1188 is current and note accompanying codes that narrow cause (fuel trims, injector, MAF, MAP, fuel pressure)
  3. With engine warm at idle, observe Bank 1 Sensor 1 waveform or AFR: a healthy narrowband sensor should switch regularly; wideband should follow commanded AFR
  4. Inspect sensor connector and wiring. Wiggle test harness while monitoring live data for intermittent changes
  5. Measure heater circuit: with connector disconnected measure resistance between heater pins and to ground for shorts; with ignition on measure heater supply voltage (consult wiring diagram)
  6. Check continuity between sensor pins and ECU connector; repair any opens/shorts
  7. Perform smoke/leak test of intake/exhaust for leaks upstream of the sensor and correct leaks found
  8. Verify fuel pressure and injector operation to ensure proper fueling; repair fuel-system faults
  9. If wiring and fuel system are good and sensor signals out of spec, replace Bank 1 Sensor 1 with OEM-equivalent and clear codes
  10. After repair, erase codes and perform road test / monitor live data to confirm normal sensor switching and normalized fuel trims

Likely causes

  • Failed or degraded Bank 1 Sensor 1
  • Open/short or intermittent wiring/connector to the sensor
  • Heater element open or no power to heater circuit
  • Vacuum/exhaust leak upstream of the sensor causing incorrect readings
  • Low/high fuel pressure or injector fault affecting AFR

Fault status

⚠️ Status
Fuel control fault detected on Bank 1 Sensor 1 — upstream oxygen/AFR sensor signal or heater circuit out of specification, affecting closed-loop fuel control.
🟡 Repair difficulty: Medium
⏱️ Diagnostic time: 1-2 hours

Similar codes

P0130 P0131 P0132 P0133 P0134 P0135
Your experience will help others
+100 karma for a short comment :)
Keep it short and practical. Up to 500 characters.
Send to email
Code

P1188

VOLKSWAGEN P — Powertrain

Linear Oxygen Sensor Compensation Resistor Short To Ground

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

Causes

  • Faulty Bank 1 Sensor 1 (upstream O2/AFR sensor)
  • Damaged wiring or poor connector contact to the sensor
  • Heater circuit failure in the sensor
  • Exhaust leaks upstream of the sensor (false air)
  • Fuel pressure or injector problems causing out-of-range AFR
  • Contaminated sensor (oil, coolant, silicone)

Symptoms

  • Check Engine Light (MIL) on
  • Poor idle quality or rough running
  • Elevated or unstable fuel trims (long or short term)
  • Reduced fuel economy
  • Hesitation, stumble or reduced drivability under load
  • Possible hard starting or stalling

What to check

  • Read freeze frame and stored data for fuel trims and sensor values
  • Scan live upstream O2/AFR sensor (Bank 1 Sensor 1) voltage or AFR trace
  • Check for additional DTCs (fuel trims, injector, MAP/MAF, fuel pressure, leaks)
  • Inspect sensor connector for corrosion, damage, or moisture
  • Visually inspect wiring harness for chafing, pinches or breaks
  • Perform smoke test or visual check for vacuum/exhaust leaks upstream of sensor

Signal parameters

  • Typical narrowband upstream O2 voltage: ~0.1–0.9 V (switching rapidly around 0.45 V)
  • Heater circuit: resistance typically low ohms (varies by sensor, often ~2–10 Ω) — consult vehicle spec
  • Sensor should switch rich/lean quickly at idle; slow or fixed readings indicate fault
  • Wideband/AFR sensors (if fitted) use different signal ranges — consult OEM spec for voltage/current/serial data

Diagnostic algorithm

  1. Connect a full-function OBD-II scanner and record freeze frame, stored codes and live data for Bank 1 Sensor 1 and fuel trims
  2. Confirm P1188 is current and note accompanying codes that narrow cause (fuel trims, injector, MAF, MAP, fuel pressure)
  3. With engine warm at idle, observe Bank 1 Sensor 1 waveform or AFR: a healthy narrowband sensor should switch regularly; wideband should follow commanded AFR
  4. Inspect sensor connector and wiring. Wiggle test harness while monitoring live data for intermittent changes
  5. Measure heater circuit: with connector disconnected measure resistance between heater pins and to ground for shorts; with ignition on measure heater supply voltage (consult wiring diagram)
  6. Check continuity between sensor pins and ECU connector; repair any opens/shorts
  7. Perform smoke/leak test of intake/exhaust for leaks upstream of the sensor and correct leaks found
  8. Verify fuel pressure and injector operation to ensure proper fueling; repair fuel-system faults
  9. If wiring and fuel system are good and sensor signals out of spec, replace Bank 1 Sensor 1 with OEM-equivalent and clear codes
  10. After repair, erase codes and perform road test / monitor live data to confirm normal sensor switching and normalized fuel trims

Likely causes

  • Failed or degraded Bank 1 Sensor 1
  • Open/short or intermittent wiring/connector to the sensor
  • Heater element open or no power to heater circuit
  • Vacuum/exhaust leak upstream of the sensor causing incorrect readings
  • Low/high fuel pressure or injector fault affecting AFR

Fault status

⚠️ Status
Fuel control fault detected on Bank 1 Sensor 1 — upstream oxygen/AFR sensor signal or heater circuit out of specification, affecting closed-loop fuel control.
🟡 Repair difficulty: Medium
⏱️ Diagnostic time: 1-2 hours

Similar codes

P0130 P0131 P0132 P0133 P0134 P0135
626

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

VOLKSWAGEN

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