Engine Coolant Temperature Too High

The engine's coolant is getting too hot, so the computer is making sure the vehicle is safe.

The engine control module (ECM) sees coolant temperatures above the programmed threshold, typically above 230°F (110°C).

Don't just throw parts at it. Walk through these in order — each step tells you whether to keep going or stop and fix what you found.

1. 11. Check coolant level in the reservoir and radiator. If low, fill to proper level and retest. Decision: If code returns, proceed to next step.
2. 22. Inspect the coolant temperature sensor wiring and connector for damage or corrosion. Repair as needed. Decision: If wiring is good, proceed to next step.
3. 33. Using a scan tool, monitor live data from the coolant temperature sensor. Compare readings to actual temperature with an infrared thermometer. Decision: If readings are off by more than 10°F (5°C), replace the sensor.
4. 44. Check the operation of the thermostat: remove it, and place it in boiling water to see if it opens at the correct temperature. Decision: If it doesn't open properly, replace the thermostat.
5. 55. Inspect the radiator for blockages or damage. If blocked, clean or replace it. Decision: If radiator is clear and problem persists, proceed to check the water pump operation.

• Low coolant level
• Faulty coolant temperature sensor
• Thermostat stuck closed
• Blocked radiator
• Failed water pump

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