OBD-II code · Powertrain (generic)
P0125 Insufficient Coolant Temperature for Closed Loop Fuel Control
The engine has run long enough that closed-loop fuel control should be active, but the coolant temperature has not risen high enough. Often caused by a stuck-open thermostat or a failed coolant temperature sensor.
Is it safe to drive with P0125?
Usually safe to drive in the short term. Get it diagnosed when convenient, sooner if the car drives differently.
Common causes
- Most likelyThermostat stuck open
- PossibleCoolant temp sensor reading low
Repair at a glance
- Difficulty
- Medium
- DIY friendly
- Often, with basic tools
- Typical labour
- 0.5–2.5 h
- Emissions test
- Likely to fail
- After the fix
- A drive cycle is needed before the light stays off
- Parts involved
- Thermostat, Coolant Temperature Sensor
Related codes
- P0122Throttle/Pedal Position Sensor "A" Low Input
- P0123Throttle/Pedal Position Sensor "A" High Input
- P0124Throttle/Pedal Position Sensor "A" Circuit Intermittent
- P0126Insufficient Coolant Temperature for Stable Operation
- P0127Intake Air Temperature Too High
- P0128Coolant Thermostat Below Regulating Temperature
Code data: OBDex open dataset (CC0). Labour times are typical ranges, not a quote.