Engine Coolant Temperature Voltage Above Normal
The engine coolant temperature is too high for normal operation.
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What it means (plain English)
The computer is reading a coolant temperature that's too warm for safe engine operation, usually above 220°F (104°C).
What the computer is actually seeing
The engine control module (ECM) is receiving a voltage signal from the coolant temperature sensor indicating temperatures above the normal threshold.
What a healthy reading looks like
Normal coolant temperature should be between 160°F and 210°F (71°C to 99°C). Above 220°F (104°C) indicates a potential problem.
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. Ensure it’s at the recommended level. If low, top it off and recheck.
- 22. Inspect the wiring and connectors to the coolant temperature sensor for damage or corrosion. Repair as needed.
- 33. Use a multimeter to test the coolant temperature sensor output. Expect a voltage around 0.5V to 4.5V depending on temperature. If it's outside this range, replace the sensor.
- 44. Start the engine and monitor the temperature with a scan tool. If the reading stays above 220°F (104°C) even with adequate coolant and a good sensor, check the operation of the thermostat and cooling fan.
Common causes
- Faulty coolant temperature sensor
- Wiring issues or poor connections
- Low coolant levels or leaks
- Thermostat stuck closed
- Cooling fan not operating properly
Typical repair cost
$$ - $$$
Related codes
Frequently asked questions
Is it safe to drive with this code?
It's best to address this issue soon. Driving with high coolant temperatures can damage the engine.
Will this code come back after clearing it?
If the underlying issue isn't fixed, it will likely return.
Why am I getting this code with a faulty fan?
The fan is responsible for cooling the engine; if it’s not working, the coolant temperature will rise, triggering this code.
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