Engine Coolant Temperature Sensor 4 Circuit Low
Voltage on the engine coolant temperature 4 sensor signal line is below the expected window. Wire shorted to ground or sensor short.
Affected components
- Engine coolant temperature sensor 4
- Wiring harness
- Ecm
Common causes
- High likelihood: Signal wire shorted to ground
- Medium likelihood: Internal sensor short
- Low likelihood: Connector pins corroded - high contact resistance
Possible 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
Diagnostic notes
- The malfunction indicator lamp may illuminate
- This code can affect emissions
Related codes
Sources
Diagnostic information is provided for reference only. Confirm the code with a compatible scan tool and follow the vehicle manufacturer's service procedures before replacing components.