Faulty Engine Coolant Temperature Sensor
The engine coolant temperature sensor is reporting out of range values.
Heads up: this code wasn't in our hand-written library yet, so DiagCoach AI built this page on the fly. Double-check critical specs against service info before condemning parts.
What it means (plain English)
The computer is getting a reading from the coolant temperature sensor that is too high or too low than what it should be, affecting how the engine runs.
What the computer is actually seeing
The Engine Control Unit (ECU) sees voltages from the coolant temperature sensor that should be between 0.5V (cold) and 4.5V (hot) but is getting values outside this range.
What a healthy reading looks like
The expected voltage should be between 0.5V and 4.5V, correlating to a temperature range of approximately -40°C to 125°C (-40°F to 257°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. Inspect the wiring and connectors of the coolant temperature sensor for any damage or corrosion. If found, repair and retest.
- 22. Check the coolant level in the reservoir. If it's low, top it off and see if the code clears.
- 33. Verify the voltage reading at the coolant temperature sensor connector using a multimeter. Look for voltages between 0.5V and 4.5V. If it's outside this range, replace the sensor.
- 44. If the voltage is within range, check the ECU for any unrelated faults that may affect readings. If no issues, it may be a problem with the ECU itself.
Common causes
- Faulty coolant temperature sensor
- Wiring issues (shorts or opens)
- Engine overheating issues
- Coolant level too low
Typical repair cost
$$ ($100 - $300)
Related codes
Frequently asked questions
Is it safe to drive with this code?
It's moderate; you can drive but should fix soon to avoid potential overheating.
Will this code come back after clearing?
If the root cause isn't fixed, it likely will return.
Why does this sensor code pair with other codes?
Multiple codes may indicate a broader issue with the cooling system or engine management.
Working a real vehicle right now?
Let DiagCoach walk you through it live with your specific symptoms, vehicle, and what you've already checked.
Start guided diagnostic →