Engine Coolant Temperature Above Normal Operating Range
The engine coolant temperature is too high, indicating an overheating condition.
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What it means (plain English)
The engine coolant sensor is showing that the engine is running hotter than it should, usually over 240°F (116°C). This might be due to a failing thermostat, a clogged radiator, or low coolant levels causing poor cooling.
What the computer is actually seeing
The engine control module (ECM) is monitoring the coolant temperature sensor and sees a temperature reading exceeding the safe threshold.
What a healthy reading looks like
Normal operating temperature should be between 180°F to 220°F (82°C to 104°C).
Guided diagnostic — the DiagCoach way
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.
- 11. Check the coolant level in the reservoir. If it's low, refill to the proper level and recheck the code after driving.
- 22. Inspect for any visible leaks in the cooling system; repair any leaks found.
- 33. Test the thermostat operation. Use a scan tool to monitor coolant temperature as the engine warms up. If it doesn't open by about 200°F (93°C), replace it.
- 44. Check the radiator for blockage and airflow issues. Ensure that it's not clogged with debris and the cooling fans are functioning when temperatures rise.
- 55. If all checks pass, test the coolant temperature sensor itself for proper operation using a multimeter. Resistance should match the expected temperature readings.
Common causes
- Low coolant level
- Faulty thermostat
- Clogged radiator
- Failed water pump
- Cooling fan issues
Typical repair cost
$$ - $$$
Related codes
Frequently asked questions
Is it safe to drive with this code?
No, it's not safe. Driving with an overheating engine can cause severe damage.
Will this issue come back after clearing the code?
It might if the underlying issue isn't resolved. Monitor coolant temperature after repairs.
Why does this code sometimes appear with low coolant?
If coolant is low, the sensor may read inaccurate temperatures, leading to the code.
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