Coolant Temperature Sensor Voltage Out of Range
Indicates the coolant temperature sensor voltage is not within expected limits.
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What it means (plain English)
The computer is saying the sensor that measures the engine coolant temperature is either sending too high or too low a voltage signal, which makes it hard to know how hot the engine really is.
What the computer is actually seeing
The engine control module expects the coolant temperature to be between 0.5V and 4.5V; if it's outside of this range constantly, this code will trigger.
What a healthy reading looks like
Coolant temp expected to be between 75°C (167°F) and 115°C (239°F); voltage from sensor should range from 0.5V to 4.5V.
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. First, check the coolant level in the reservoir and radiator. Ensure it's at the proper level. If low, refill and retest.
- 22. Inspect the wiring and connector at the coolant temperature sensor for any signs of wear, damage, or corrosion. Repair as needed if found.
- 33. Using a multimeter, measure the voltage at the coolant temperature sensor while the engine is at operating temperature. Expected voltage should be between 0.5V and 4.5V. If out of range, replace the sensor.
- 44. If the voltage is within the expected range but the code persists, check the wiring from the coolant sensor to the ECM for continuity and shorts. Use a wiring diagram for guidance.
Common causes
- Faulty coolant temperature sensor
- Wiring issues or harness damage
- Poor connection at the sensor or ECM
- Coolant level too low affecting sensor performance
Typical repair cost
$$
Related codes
Frequently asked questions
Is it safe to drive with this code?
It's best to address this code soon. Running with incorrect temperature readings can lead to overheating and engine damage.
Will this code come back after clearing?
If the underlying issue isn't fixed, yes, the code will likely return.
Why does this code sometimes pair with SPN 4117?
SPN 4117 indicates a similar problem, suggesting there may be multiple issues with the coolant temperature sensor or circuit.
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