Engine Coolant Temperature Too High

The computer thinks the engine is overheating because the coolant temperature is too high, which can cause serious damage if not addressed.

The engine control unit (ECU) shows a coolant temperature reading that exceeds the predetermined maximum threshold, typically over 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 the coolant level in the reservoir and radiator; it should be between the minimum and maximum marks. If low, add the appropriate coolant and check for leaks.
2. 22. Inspect all coolant hoses for leaks or blockages; repair any issues found before proceeding.
3. 33. Test the operation of the thermostat by observing temperature changes as the engine warms up. If it stays closed or opens at incorrect temperatures, replace it.
4. 44. Check the function of the water pump. Look for leaks or listen for unusual noises indicating wear or failure. If defective, replace it.
5. 55. Use a scan tool to check the coolant temperature sensor signal. At operating temperature, it should read close to engine temperature. If not, replace the sensor.

• Low coolant level
• Faulty thermostat
• Inoperative water pump
• Blocked coolant passages
• Faulty temperature sensor

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