Powertrain
generic / SAE
P01E5
Engine Coolant Temperature Sensor 3 Circuit Low
ECT sensor 3 signal voltage below expected range. The engine coolant temperature sensor feeds warm-up enrichment, fan control and closed-loop entry — a stuck-cold reading keeps the engine in open loop and rich forever.
SystemPowertrain
Typegeneric / SAE
GroupP0
Range / number1 / E5
Possible causes
- Signal wire shorted to ground high
- Connector pins corroded - high contact resistance low
- Harness chafing through insulation low
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: 40–250 €
- Estimated time: 0.3–1.5 h
- Component: ect sensor 3
- Component: sensor wiring
- MIL / check engine light
- emissions-relevant
Sources
References
sae:J2012