Code
P0125
Generic
P — Powertrain
Insufficient Coolant Temperature for Closed Loop Fuel Control
Views:
UK: 15
EN: 67
RU: 48
AI status
Completed
Completed
100%
Causes
- Stuck‑open or failed thermostat (engine not reaching operating temperature)
- Low or contaminated engine coolant / air trapped in cooling system
- Faulty engine coolant temperature (ECT) sensor or poor sensor circuit connection
- Wiring harness damage or connector corrosion in ECT circuit
- Water pump circulation failure or blocked coolant passages
- Aftermarket thermostat or incorrect thermostat installed
Symptoms
- Extended cold‑engine warm‑up time
- Long engine run-in rich condition / poor fuel economy
- Rough or high idle until engine warms
- Increased cold emissions / failed warm‑up emissions test
- Heater output may be reduced or delayed
What to check
- Retrieve freeze‑frame and live data with a scan tool: monitor ECT sensor value from cold start and time to reach operating temp
- Visual inspection: coolant level, leaks, radiator and hoses, thermostat housing and sensor connectors
- Verify correct thermostat type and installation if recently replaced
- Check for stored related codes (P0115/P0117/P0118/P0128) and pending faults
- Inspect ECT sensor wiring for damage, corrosion, poor pin contact
- Confirm vehicle was a genuine cold start (ambient temp) when code set
Signal parameters
- Expected warm‑up: ECT should rise steadily from ambient to ~70–95 °C (160–203 °F) depending on engine/thermostat
- Typical closed‑loop entry temperature: often ~60–80 °C (140–176 °F) — manufacturer specific
- ECT sensor output: typical 0–5 V thermistor signal (voltage decreases as temperature rises) or resistance falls with rising temp
- Time to reach operating temp: usually within several minutes under normal ambient; code sets if temp stays below threshold past a manufacturer time limit
Diagnostic algorithm
- Verify conditions: confirm freeze‑frame shows cold start and note ambient temperature and elapsed cranking/running time.
- Scan tool live data: start engine cold and record ECT temperature every 30 seconds. If temp rises normally, retest for intermittent behavior.
- Check coolant level and condition with engine cold. Top up to specified level and bleed air from system per vehicle procedure; retest warm‑up.
- Inspect thermostat: with cold engine, remove thermostat housing (if applicable) or perform temperature drop test across radiator and engine to see if thermostat opens. Replace if stuck open or out of spec.
- Test ECT sensor: measure sensor resistance or voltage vs temperature and compare to manufacturer chart. Wiggle test wiring and backprobe connector to check for intermittent faults.
- Inspect and test wiring: check for open/short/poor ground between sensor and ECM, repair damaged wiring or corroded connector pins.
- Check cooling system flow: verify water pump operation and look for clogged radiator or blocked passages; pressure test cooling system for leaks.
- If thermostat and sensor are good, replace suspect components one at a time starting with thermostat (common and inexpensive) and retest. Clear codes and perform multiple cold starts to confirm repair.
- If code persists after repairs, consult OEM service information for specific timing/temperature thresholds and ECM diagnostic tests.
Likely causes
- Thermostat stuck open — most common cause
- Low coolant level or air in system preventing proper flow/temperature rise
- Open/short or high resistance in ECT sensor wiring or corroded connector
- Faulty ECT sensor giving false low temperature reading
- Weak coolant circulation (worn water pump or clogged radiator)
Fault status
Status
Insufficient coolant temperature detected for closed‑loop fuel control — engine not reaching expected temperature within allowed time. Check thermostat, coolant level, ECT sensor and related wiring.
Repair difficulty: Medium
Diagnostic time: 0.5-2.0 hours
Similar codes
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Workshop ManualLand Rover Defender Workshop Manual Supplement & Body Repair Manual (1999 & 2002 MY)
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Workshop ManualYour experience will help others
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Code
P0125
GWM
P — Powertrain
- Coolant temperature too low or too high
Views:
UK: 2
EN: 10
RU: 13
AI status
Completed
Completed
100%
Causes
- Stuck‑open or failed thermostat (engine not reaching operating temperature)
- Low or contaminated engine coolant / air trapped in cooling system
- Faulty engine coolant temperature (ECT) sensor or poor sensor circuit connection
- Wiring harness damage or connector corrosion in ECT circuit
- Water pump circulation failure or blocked coolant passages
- Aftermarket thermostat or incorrect thermostat installed
Symptoms
- Extended cold‑engine warm‑up time
- Long engine run-in rich condition / poor fuel economy
- Rough or high idle until engine warms
- Increased cold emissions / failed warm‑up emissions test
- Heater output may be reduced or delayed
What to check
- Retrieve freeze‑frame and live data with a scan tool: monitor ECT sensor value from cold start and time to reach operating temp
- Visual inspection: coolant level, leaks, radiator and hoses, thermostat housing and sensor connectors
- Verify correct thermostat type and installation if recently replaced
- Check for stored related codes (P0115/P0117/P0118/P0128) and pending faults
- Inspect ECT sensor wiring for damage, corrosion, poor pin contact
- Confirm vehicle was a genuine cold start (ambient temp) when code set
Signal parameters
- Expected warm‑up: ECT should rise steadily from ambient to ~70–95 °C (160–203 °F) depending on engine/thermostat
- Typical closed‑loop entry temperature: often ~60–80 °C (140–176 °F) — manufacturer specific
- ECT sensor output: typical 0–5 V thermistor signal (voltage decreases as temperature rises) or resistance falls with rising temp
- Time to reach operating temp: usually within several minutes under normal ambient; code sets if temp stays below threshold past a manufacturer time limit
Diagnostic algorithm
- Verify conditions: confirm freeze‑frame shows cold start and note ambient temperature and elapsed cranking/running time.
- Scan tool live data: start engine cold and record ECT temperature every 30 seconds. If temp rises normally, retest for intermittent behavior.
- Check coolant level and condition with engine cold. Top up to specified level and bleed air from system per vehicle procedure; retest warm‑up.
- Inspect thermostat: with cold engine, remove thermostat housing (if applicable) or perform temperature drop test across radiator and engine to see if thermostat opens. Replace if stuck open or out of spec.
- Test ECT sensor: measure sensor resistance or voltage vs temperature and compare to manufacturer chart. Wiggle test wiring and backprobe connector to check for intermittent faults.
- Inspect and test wiring: check for open/short/poor ground between sensor and ECM, repair damaged wiring or corroded connector pins.
- Check cooling system flow: verify water pump operation and look for clogged radiator or blocked passages; pressure test cooling system for leaks.
- If thermostat and sensor are good, replace suspect components one at a time starting with thermostat (common and inexpensive) and retest. Clear codes and perform multiple cold starts to confirm repair.
- If code persists after repairs, consult OEM service information for specific timing/temperature thresholds and ECM diagnostic tests.
Likely causes
- Thermostat stuck open — most common cause
- Low coolant level or air in system preventing proper flow/temperature rise
- Open/short or high resistance in ECT sensor wiring or corroded connector
- Faulty ECT sensor giving false low temperature reading
- Weak coolant circulation (worn water pump or clogged radiator)
Fault status
Status
Insufficient coolant temperature detected for closed‑loop fuel control — engine not reaching expected temperature within allowed time. Check thermostat, coolant level, ECT sensor and related wiring.
Repair difficulty: Medium
Diagnostic time: 0.5-2.0 hours
Similar codes
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Code
P0125
HUMMER
P — Powertrain
Engine Coolant Temperature (ECT) Insufficient for Closed Loop Fuel Control
Views:
UK: 7
EN: 44
RU: 34
AI status
Completed
Completed
100%
Causes
- Stuck‑open or failed thermostat (engine not reaching operating temperature)
- Low or contaminated engine coolant / air trapped in cooling system
- Faulty engine coolant temperature (ECT) sensor or poor sensor circuit connection
- Wiring harness damage or connector corrosion in ECT circuit
- Water pump circulation failure or blocked coolant passages
- Aftermarket thermostat or incorrect thermostat installed
Symptoms
- Extended cold‑engine warm‑up time
- Long engine run-in rich condition / poor fuel economy
- Rough or high idle until engine warms
- Increased cold emissions / failed warm‑up emissions test
- Heater output may be reduced or delayed
What to check
- Retrieve freeze‑frame and live data with a scan tool: monitor ECT sensor value from cold start and time to reach operating temp
- Visual inspection: coolant level, leaks, radiator and hoses, thermostat housing and sensor connectors
- Verify correct thermostat type and installation if recently replaced
- Check for stored related codes (P0115/P0117/P0118/P0128) and pending faults
- Inspect ECT sensor wiring for damage, corrosion, poor pin contact
- Confirm vehicle was a genuine cold start (ambient temp) when code set
Signal parameters
- Expected warm‑up: ECT should rise steadily from ambient to ~70–95 °C (160–203 °F) depending on engine/thermostat
- Typical closed‑loop entry temperature: often ~60–80 °C (140–176 °F) — manufacturer specific
- ECT sensor output: typical 0–5 V thermistor signal (voltage decreases as temperature rises) or resistance falls with rising temp
- Time to reach operating temp: usually within several minutes under normal ambient; code sets if temp stays below threshold past a manufacturer time limit
Diagnostic algorithm
- Verify conditions: confirm freeze‑frame shows cold start and note ambient temperature and elapsed cranking/running time.
- Scan tool live data: start engine cold and record ECT temperature every 30 seconds. If temp rises normally, retest for intermittent behavior.
- Check coolant level and condition with engine cold. Top up to specified level and bleed air from system per vehicle procedure; retest warm‑up.
- Inspect thermostat: with cold engine, remove thermostat housing (if applicable) or perform temperature drop test across radiator and engine to see if thermostat opens. Replace if stuck open or out of spec.
- Test ECT sensor: measure sensor resistance or voltage vs temperature and compare to manufacturer chart. Wiggle test wiring and backprobe connector to check for intermittent faults.
- Inspect and test wiring: check for open/short/poor ground between sensor and ECM, repair damaged wiring or corroded connector pins.
- Check cooling system flow: verify water pump operation and look for clogged radiator or blocked passages; pressure test cooling system for leaks.
- If thermostat and sensor are good, replace suspect components one at a time starting with thermostat (common and inexpensive) and retest. Clear codes and perform multiple cold starts to confirm repair.
- If code persists after repairs, consult OEM service information for specific timing/temperature thresholds and ECM diagnostic tests.
Likely causes
- Thermostat stuck open — most common cause
- Low coolant level or air in system preventing proper flow/temperature rise
- Open/short or high resistance in ECT sensor wiring or corroded connector
- Faulty ECT sensor giving false low temperature reading
- Weak coolant circulation (worn water pump or clogged radiator)
Fault status
Status
Insufficient coolant temperature detected for closed‑loop fuel control — engine not reaching expected temperature within allowed time. Check thermostat, coolant level, ECT sensor and related wiring.
Repair difficulty: Medium
Diagnostic time: 0.5-2.0 hours
Similar codes
Your experience will help others
+100 karma for a short comment :)
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Code
P0125
LAND ROVER
P — Powertrain
Insufficient coolant temperature for control of fuel in circuit
Views:
UK: 4
EN: 25
RU: 26
AI status
Completed
Completed
100%
Causes
- Stuck‑open or failed thermostat (engine not reaching operating temperature)
- Low or contaminated engine coolant / air trapped in cooling system
- Faulty engine coolant temperature (ECT) sensor or poor sensor circuit connection
- Wiring harness damage or connector corrosion in ECT circuit
- Water pump circulation failure or blocked coolant passages
- Aftermarket thermostat or incorrect thermostat installed
Symptoms
- Extended cold‑engine warm‑up time
- Long engine run-in rich condition / poor fuel economy
- Rough or high idle until engine warms
- Increased cold emissions / failed warm‑up emissions test
- Heater output may be reduced or delayed
What to check
- Retrieve freeze‑frame and live data with a scan tool: monitor ECT sensor value from cold start and time to reach operating temp
- Visual inspection: coolant level, leaks, radiator and hoses, thermostat housing and sensor connectors
- Verify correct thermostat type and installation if recently replaced
- Check for stored related codes (P0115/P0117/P0118/P0128) and pending faults
- Inspect ECT sensor wiring for damage, corrosion, poor pin contact
- Confirm vehicle was a genuine cold start (ambient temp) when code set
Signal parameters
- Expected warm‑up: ECT should rise steadily from ambient to ~70–95 °C (160–203 °F) depending on engine/thermostat
- Typical closed‑loop entry temperature: often ~60–80 °C (140–176 °F) — manufacturer specific
- ECT sensor output: typical 0–5 V thermistor signal (voltage decreases as temperature rises) or resistance falls with rising temp
- Time to reach operating temp: usually within several minutes under normal ambient; code sets if temp stays below threshold past a manufacturer time limit
Diagnostic algorithm
- Verify conditions: confirm freeze‑frame shows cold start and note ambient temperature and elapsed cranking/running time.
- Scan tool live data: start engine cold and record ECT temperature every 30 seconds. If temp rises normally, retest for intermittent behavior.
- Check coolant level and condition with engine cold. Top up to specified level and bleed air from system per vehicle procedure; retest warm‑up.
- Inspect thermostat: with cold engine, remove thermostat housing (if applicable) or perform temperature drop test across radiator and engine to see if thermostat opens. Replace if stuck open or out of spec.
- Test ECT sensor: measure sensor resistance or voltage vs temperature and compare to manufacturer chart. Wiggle test wiring and backprobe connector to check for intermittent faults.
- Inspect and test wiring: check for open/short/poor ground between sensor and ECM, repair damaged wiring or corroded connector pins.
- Check cooling system flow: verify water pump operation and look for clogged radiator or blocked passages; pressure test cooling system for leaks.
- If thermostat and sensor are good, replace suspect components one at a time starting with thermostat (common and inexpensive) and retest. Clear codes and perform multiple cold starts to confirm repair.
- If code persists after repairs, consult OEM service information for specific timing/temperature thresholds and ECM diagnostic tests.
Likely causes
- Thermostat stuck open — most common cause
- Low coolant level or air in system preventing proper flow/temperature rise
- Open/short or high resistance in ECT sensor wiring or corroded connector
- Faulty ECT sensor giving false low temperature reading
- Weak coolant circulation (worn water pump or clogged radiator)
Fault status
Status
Insufficient coolant temperature detected for closed‑loop fuel control — engine not reaching expected temperature within allowed time. Check thermostat, coolant level, ECT sensor and related wiring.
Repair difficulty: Medium
Diagnostic time: 0.5-2.0 hours
Similar codes
Workshop Manuals
Repair manuals for LAND ROVER
3
Land Rover Defender 300Tdi — Workshop Manual (1996 model year)
Workshop ManualLand Rover Defender Workshop Manual Supplement & Body Repair Manual (1999 & 2002 MY)
Workshop ManualLand Rover Range Rover — Electrical Library (LRL 0453ENG, 2002)
Workshop ManualYour experience will help others
+100 karma for a short comment :)
Was this AI description helpful?
Your feedback helps improve AI descriptions.
👍 Like
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Send to email
Code
P0125
MITSUBISHI
P — Powertrain
Feedback system
Views:
UK: 6
EN: 41
RU: 29
AI status
Completed
Completed
100%
Causes
- Stuck‑open or failed thermostat (engine not reaching operating temperature)
- Low or contaminated engine coolant / air trapped in cooling system
- Faulty engine coolant temperature (ECT) sensor or poor sensor circuit connection
- Wiring harness damage or connector corrosion in ECT circuit
- Water pump circulation failure or blocked coolant passages
- Aftermarket thermostat or incorrect thermostat installed
Symptoms
- Extended cold‑engine warm‑up time
- Long engine run-in rich condition / poor fuel economy
- Rough or high idle until engine warms
- Increased cold emissions / failed warm‑up emissions test
- Heater output may be reduced or delayed
What to check
- Retrieve freeze‑frame and live data with a scan tool: monitor ECT sensor value from cold start and time to reach operating temp
- Visual inspection: coolant level, leaks, radiator and hoses, thermostat housing and sensor connectors
- Verify correct thermostat type and installation if recently replaced
- Check for stored related codes (P0115/P0117/P0118/P0128) and pending faults
- Inspect ECT sensor wiring for damage, corrosion, poor pin contact
- Confirm vehicle was a genuine cold start (ambient temp) when code set
Signal parameters
- Expected warm‑up: ECT should rise steadily from ambient to ~70–95 °C (160–203 °F) depending on engine/thermostat
- Typical closed‑loop entry temperature: often ~60–80 °C (140–176 °F) — manufacturer specific
- ECT sensor output: typical 0–5 V thermistor signal (voltage decreases as temperature rises) or resistance falls with rising temp
- Time to reach operating temp: usually within several minutes under normal ambient; code sets if temp stays below threshold past a manufacturer time limit
Diagnostic algorithm
- Verify conditions: confirm freeze‑frame shows cold start and note ambient temperature and elapsed cranking/running time.
- Scan tool live data: start engine cold and record ECT temperature every 30 seconds. If temp rises normally, retest for intermittent behavior.
- Check coolant level and condition with engine cold. Top up to specified level and bleed air from system per vehicle procedure; retest warm‑up.
- Inspect thermostat: with cold engine, remove thermostat housing (if applicable) or perform temperature drop test across radiator and engine to see if thermostat opens. Replace if stuck open or out of spec.
- Test ECT sensor: measure sensor resistance or voltage vs temperature and compare to manufacturer chart. Wiggle test wiring and backprobe connector to check for intermittent faults.
- Inspect and test wiring: check for open/short/poor ground between sensor and ECM, repair damaged wiring or corroded connector pins.
- Check cooling system flow: verify water pump operation and look for clogged radiator or blocked passages; pressure test cooling system for leaks.
- If thermostat and sensor are good, replace suspect components one at a time starting with thermostat (common and inexpensive) and retest. Clear codes and perform multiple cold starts to confirm repair.
- If code persists after repairs, consult OEM service information for specific timing/temperature thresholds and ECM diagnostic tests.
Likely causes
- Thermostat stuck open — most common cause
- Low coolant level or air in system preventing proper flow/temperature rise
- Open/short or high resistance in ECT sensor wiring or corroded connector
- Faulty ECT sensor giving false low temperature reading
- Weak coolant circulation (worn water pump or clogged radiator)
Fault status
Status
Insufficient coolant temperature detected for closed‑loop fuel control — engine not reaching expected temperature within allowed time. Check thermostat, coolant level, ECT sensor and related wiring.
Repair difficulty: Medium
Diagnostic time: 0.5-2.0 hours
Similar codes
Your experience will help others
+100 karma for a short comment :)
Was this AI description helpful?
Your feedback helps improve AI descriptions.
👍 Like
0
👎 Dislike
0
Send to email