Radiator Coolant Temperature/Engine Coolant Temperature Correlation
Difference between radiator outlet and engine coolant temperatures is implausible — typically indicates a stuck thermostat.
Affected components
- Thermostat
- Radiator coolant temp sensor
- Engine coolant temp sensor
Common causes
- High likelihood: Thermostat stuck open (slow warm-up)
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
- A drive cycle may be required after repair
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.