OBD-II code · Powertrain (generic)
P01F0 Coolant Temperature Relapsed Below Diagnostic Monitoring Temperature
Coolant temperature dropped below the diagnostic monitoring threshold after warm-up. Often thermostat stuck open or stuck-open coolant heater bypass.
Is it safe to drive with P01F0?
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
Repair at a glance
- Difficulty
- Medium
- DIY friendly
- Often, with basic tools
- Typical labour
- 0.5–3 h
- Emissions test
- Likely to fail
- After the fix
- A drive cycle is needed before the light stays off
- Parts involved
- Thermostat, Coolant Circuit
Related codes
Code data: OBDex open dataset (CC0). Labour times are typical ranges, not a quote.