Vehicle's Engine Over-temperature

The engine coolant is getting too hot, which could cause serious damage if not addressed.

The engine control unit (ECU) is reading the coolant temperature sensor (CTS) voltage and when it exceeds the predetermined threshold, typically above 240°F (116°C), this code is triggered.

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; ensure it is at the proper level. Decision: If low, top off and retest. If okay, proceed to Step 2.
2. 22. Inspect for any visible leaks in the coolant hoses and connections. Decision: If leaks found, repair and retest. If none, proceed to Step 3.
3. 33. Test the coolant temperature sensor (CTS) for proper operation. Measure voltage with a multimeter; it should vary between 0.5V (cold) to 4.5V (hot). Decision: If out of range, replace the CTS. If in range, proceed to Step 4.
4. 44. Inspect the thermostat operation by checking engine temperature. If the engine fails to reach normal operating temperature or overheats, replace the thermostat. Decision: If thermostat is fine, proceed to Step 5.
5. 55. Look for any signs of excessive engine load (e.g., heavy towing or poor airflow to the radiator). Decision: If found, address the load issues. If not, further diagnose the engine for underlying mechanical problems.

• Low coolant level
• Failed coolant temperature sensor (CTS)
• Coolant leaks or blockages
• Faulty thermostat
• Excessive engine load or overheating due to other mechanical issues

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