Engine Coolant Temperature Too High

The computer monitors the engine coolant temperature to prevent overheating. If it reads too high, it could mean the engine is at risk of damage due to excessive heat.

The engine control module (ECM) checks the temperature sensor and expects values between 180°F and 220°F (82°C and 104°C). If it detects a temperature above 230°F (110°C), it triggers this code.

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 engine coolant level. If low, top off the coolant and check for leaks before proceeding. Decision: If low and leaks are found, repair the leak; if coolant is normal, proceed to step 2.
2. 22. Inspect the wiring and connectors at the coolant temperature sensor for damages or corrosion. Decision: If damaged, repair or replace as necessary; if wiring is intact, proceed to step 3.
3. 33. Test the coolant temperature sensor with a multimeter while monitoring with a scan tool. Expected resistance should match specifications at various temperatures. Decision: If the sensor reading is incorrect, replace it; if readings are accurate, proceed to step 4.
4. 44. Check the thermostat operation by feeling the upper radiator hose. If it doesn’t get hot after the engine reaches operating temperature (around 180°F), the thermostat might be stuck closed. Decision: Replace thermostat if it’s not opening; if it opens and engine is still hot, look for potential blockages in radiator or issues with the water pump.

• Low coolant level due to leaks
• Faulty thermostat stuck closed
• Blocked radiator or cooling passages
• Failed water pump
• Wiring issues to the coolant temperature sensor

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