OBD-II code · Powertrain (generic)
P0115 Engine Coolant Temperature Sensor Circuit Malfunction
A general fault has been detected in the engine coolant temperature (ECT) sensor circuit. The ECU uses ECT for fuel enrichment during cold start, fan control, and closed-loop entry timing.
Is it safe to drive with P0115?
Usually safe to drive in the short term. Get it diagnosed when convenient, sooner if the car drives differently.
Common causes
- Most likelyCoolant temperature sensor failed
- PossibleWiring or connector fault
Symptoms
- Check engine light on
- Cooling fan runs constantly or not at all
- Cabin heater weak or excessively hot
- Possible long warm-up time or hard cold start
Repair at a glance
- Difficulty
- Easy
- DIY friendly
- Often, with basic tools
- Typical labour
- 0.3–1.5 h
- Emissions test
- Likely to fail
- After the fix
- A drive cycle is needed before the light stays off
- Parts involved
- Coolant Temperature Sensor, Coolant Temperature Sensor Wiring
Related codes
Code data: OBDex open dataset (CC0). Labour times are typical ranges, not a quote.