Engine Coolant Temperature High
The engine coolant temperature is too high for normal operations.
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What it means (plain English)
The computer is detecting that the coolant is hotter than it should be, usually over 230°F (110°C), which can lead to overheating.
What the computer is actually seeing
The engine control module (ECM) sees a coolant temperature sensor (CTS) reading that exceeds the normal operating range, usually over 230°F (110°C).
What a healthy reading looks like
Normal coolant temperature should be between 180°F (82°C) and 220°F (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 coolant level in the reservoir. It should be above minimum. If low, add coolant and check for leaks.
- 22. Inspect wiring and connectors at the coolant temperature sensor for damage or corrosion. Fix any issues found.
- 33. Use a scan tool to monitor the coolant temperature sensor reading in real-time. Should be between 180°F (82°C) and 220°F (104°C) under normal operating conditions.
- 44. If the reading is still high, allow the vehicle to cool and then check the thermostat by removing it and testing its operation. Replace if stuck open or closed.
- 55. Check for any blockages in the radiator or hoses that could restrict coolant flow. Clear any found.
Common causes
- Faulty coolant temperature sensor
- Low coolant level
- Cooling system leaks
- Faulty thermostat
- Blocked radiator
- Bad wiring or connectors to the sensor
Typical repair cost
$$
Related codes
Frequently asked questions
Is it safe to drive with this code active?
No, it can lead to engine overheating and potential damage.
Will this code come back after clearing it?
Yes, if the underlying issue is not fixed, the code will return.
Why does this code appear with other sensor codes?
High coolant temperature can affect sensor performance and trigger multiple codes.
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