Powertrain
generic / SAE
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.
SystemPowertrain
Typegeneric / SAE
GroupP0
Range / number1 / 15
Possible causes
- Coolant temperature sensor failed high
- Wiring or connector fault medium
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
Inspection / repair
- Difficulty: easy
- DIY: possible
- Estimated cost: 30–200 €
- Estimated time: 0.3–1.5 h
- Component: coolant temperature sensor
- Component: coolant temperature sensor wiring
- MIL / check engine light
- emissions-relevant
- drive cycle required
Sources
References
sae:J2012