Radiator Coolant Temperature Sensor Circuit Range/Performance
Radiator coolant sensor reading implausible compared to engine coolant or expected behavior. 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.
Affected components
- Radiator coolant temp sensor
- Thermostat
Common causes
- High likelihood: Thermostat stuck open
- Low likelihood: Sensor element aged beyond calibration window
- Low likelihood: Sensor mounting loose - signal damping
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.