Engine Coolant Temperature Sensor
Indicates an issue with the engine coolant temperature sensor or its circuit.
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What it means (plain English)
The engine coolant temperature sensor measures the temperature of the coolant flowing through the engine. If this sensor is faulty, the engine may not get the right data to adjust fuel and timing, which can lead to performance issues.
What the computer is actually seeing
The engine control module (ECM) expects the coolant temperature to fall within a specific range. If the sensor reports a temperature that is too high or too low (outside of expected values), the ECM triggers a fault code.
What a healthy reading looks like
The expected value range is typically between 75°C and 110°C (167°F to 230°F) during normal operation.
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. If low, refill it and see if the code returns. If not low, go to step 2.
- 22. Inspect the wiring and connectors for the coolant temperature sensor. Look for damage, corrosion, or loose connections. Fix any issues found and retest.
- 33. Use a scan tool to monitor the coolant temperature readings as the engine warms up. Compare readings to expected values. If incorrect, replace the sensor. If readings are correct, further diagnose the ECM.
Common causes
- Faulty engine coolant temperature sensor
- Wiring or connector issues in the sensor circuit
- Low coolant level affecting sensor readings
- Corroded or damaged connectors
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 keep an eye on engine temperature; if it overheats, stop immediately.
Will this code come back after clearing?
If the underlying issue isn’t fixed, yes, it will likely come back.
Why does it pair with other sensor codes?
Faulty sensors can influence each other's performance. If one fails, it can cause incorrect readings in related systems.
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