Coolant Temperature Relapsed Below Diagnostic Monitoring Temperature
Coolant temperature dropped below the diagnostic monitoring threshold after warm-up. Often thermostat stuck open or stuck-open coolant heater bypass.
Affected components
- Thermostat
- Coolant circuit
Common causes
- High likelihood: Thermostat stuck open
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.