Engine Coolant Temperature Sensor Out of Range
The engine coolant temperature sensor is reporting a temperature outside the expected range.
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What it means (plain English)
The engine coolant temperature sensor measures how hot the engine coolant is. If it reads too high or too low, the engine control unit (ECU) thinks there's a problem and might adjust engine performance.
What the computer is actually seeing
The ECU monitors the coolant temperature sensor signal, looking for voltage levels corresponding to temperatures between 180°F and 220°F (82°C to 104°C). If the voltage is above 4.8V or below 0.1V, it throws this code.
What a healthy reading looks like
Expected voltage range is 0.5V to 4.5V representing coolant temperatures from 180°F to 220°F.
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 engine coolant level. Ensure it's within the proper range.
- 22. Visually inspect the wiring and connector for damage or corrosion.
- 33. Use a multimeter to check the voltage at the coolant temperature sensor connector with the ignition on. Expected voltage should be between 0.5V and 4.5V.
- 44. If voltage is out of range, replace the coolant temperature sensor.
- 55. If sensor tests good, test the wiring continuity from the sensor to the ECM. Open or short will affect readings.
- 66. If wiring is good but still getting the code, check for any erratic readings when the engine is running by monitoring live data with a scan tool.
Common causes
- Faulty coolant temperature sensor
- Open or short in the sensor wiring
- Poor connections at the sensor or ECU
- Coolant level too low
- Thermostat stuck open or closed
Typical repair cost
$$
Related codes
Frequently asked questions
Is it safe to drive with this code?
It's a moderate severity code. You can drive, but the engine may run inefficiently, and overheating could occur.
Will this code come back after clearing?
If the underlying issue isn't fixed, yes, this code will likely reappear.
Why does this code sometimes pair with SPN 1008?
SPN 1008 indicates the engine temperature is too high, which can occur if the coolant temperature sensor is faulty.
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