Common Symptoms
- Check engine light illuminated
- Engine runs rich or poor fuel economy
- Hard starting when engine is warm
- Cooling fans run continuously
- Engine temperature gauge reads abnormally high or pegged
- Black smoke from exhaust under acceleration
Most Likely Root Causes
- Faulty engine coolant temperature sensor
- Damaged or shorted wiring harness to coolant temperature sensor
- Corroded or loose connector at coolant temperature sensor
- Short to voltage in sensor circuit wiring
- Failed engine control module
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Component Location
The engine coolant temperature sensor is typically threaded into the engine block, cylinder head, or upper radiator hose near the thermostat housing.
Manufacturer Notes
High input codes typically indicate the ECM is reading a sensor signal voltage that is too high, suggesting an open circuit or short to power condition.
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