Engine Coolant Temperature Above Normal Operating Range
The engine coolant temperature has exceeded the normal operating range.
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What it means (plain English)
When the engine coolant temperature gets too high, it means the engine is running hotter than it should. This can be caused by low coolant levels, a bad thermostat, or a blocked radiator.
What the computer is actually seeing
The module monitors coolant temperature. It expects the temperature to be between about 180°F (82°C) and 220°F (104°C). If it sees a temperature above 220°F (104°C) for more than a defined period (usually a few seconds), it sets this code.
What a healthy reading looks like
Engine coolant temperature should be between 180°F (82°C) and 220°F (104°C) under normal operating conditions.
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. Is it low? If yes, fill to the proper level and recheck. If not low, proceed to step 2.
- 22. Inspect the coolant temperature sensor connector and wiring for damage or corrosion. Is everything intact? If yes, replace the sensor, if no, repair as needed and recheck.
- 33. With a scan tool, monitor the engine coolant temperature while the engine is running. Is it exceeding 220°F (104°C) during operation? If yes, proceed to step 4. If no, the issue may be intermittent or wiring related, continue to monitor.
- 44. Check the thermostat operation. Remove and test the thermostat in hot water, does it fully open at manufacturer specified temperature? If not, replace the thermostat. If it works correctly, proceed to step 5.
- 55. Inspect the radiator for blockages or poor airflow. Can you easily see through the radiator core? If blocked, clean or replace the radiator.
Common causes
- Low coolant level
- Faulty coolant temperature sensor
- Thermostat stuck closed
- Radiator blockage
- Cooling fan failure
Typical repair cost
$$$
Related codes
Frequently asked questions
Is it safe to drive with this code?
No, it’s not safe to drive. The engine could overheat, leading to severe damage.
Will the code come back after I fix it?
If the underlying issue is resolved, the code should not return. If there’s still a problem, yes, it might come back.
Why does this code pair with low coolant level?
Low coolant causes the engine to run hotter, which triggers this temperature code.
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