Engine Temperature Sensor Circuit Low
The engine temperature sensor signal is too low.
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What it means (plain English)
The computer is reading a temperature that's lower than what it should be for normal engine operation, indicating a potential issue with the temperature sensor or wiring.
What the computer is actually seeing
The Engine Control Module (ECM) expects to see a signal from the engine temperature sensor within a range of 0.5V to 4.5V, corresponding to temperatures from about -40°C to +125°C. A value below 0.5V is considered too low.
What a healthy reading looks like
0.5V to 4.5V; temperatures between -40°C and +125°C are typical.
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.
- 1Confirm there are no leaks in the coolant system and the level is adequate.
- 2Inspect the wiring and connectors for damage, corrosion, or loose connections.
- 3Test the resistance of the engine temperature sensor; it should change with temperature. Cold engine should read around 2,500 to 3,500 ohms at 25°C, and decrease as it heats up.
- 4Check the voltage at the sensor connector with the engine running; it should fall within expected values (0.5V to 4.5V). If it's lower, replace the sensor.
- 5If the sensor checks out, inspect the engine control module for faults.
Common causes
- Faulty temperature sensor
- Wiring or connector issues (corrosion, breaks)
- Poor engine coolant level (low coolant might affect readings)
- Faulty ECM
- Short circuits in sensor circuit
Typical repair cost
$$$ - $$$$
Related codes
Frequently asked questions
Is it safe to drive with this code active?
It's moderate; you should fix it soon, especially if the temperature readings seem incorrect.
Will this code come back after clearing?
Yes, it can return if the underlying issue isn't fixed.
Why does this code sometimes pair with other codes?
Multiple sensor failures or related wiring issues can trigger several codes at once.
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