Engine Coolant Temperature Sensor Out of Range
Engine coolant temperature sensor reading is outside expected values.
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What it means (plain English)
The engine coolant temperature sensor measures the temperature of the engine coolant to help manage engine performance. When it reads too high or too low, it signals potential overheating or cooling issues.
What the computer is actually seeing
The engine control module (ECM) computes the coolant temperature based on sensor voltage. A normal operating range is typically between 175°F and 225°F (80°C to 107°C). If the voltage exceeds 4.9V or drops below 0.1V, the ECM flags this code.
What a healthy reading looks like
Normal coolant temperature should read between 175°F (80°C) and 225°F (107°C). Values outside this range trigger the fault code.
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 coolant level in the reservoir. Is it within the normal range?
- 22. Inspect the wiring and connectors to the coolant temperature sensor for damage or corrosion. Any visible issues?
- 33. Measure the voltage output at the coolant temperature sensor harness with a multimeter. Is it between 0.1V and 4.9V?
- 44. If the voltage is out of range, replace the coolant temperature sensor. Did the problem resolve?
- 55. If the voltage is correct, check ECM inputs. Using a scan tool, are other sensor readings normal?
- 66. If problems persist with correct readings, consider testing or replacing the ECM.
Common causes
- Faulty engine coolant temperature sensor
- Wiring issues or short circuit between sensor and ECM
- Low coolant levels or coolant leaks
- Failing ECM (rare)
Typical repair cost
$$
Related codes
Frequently asked questions
Can I drive with this code?
Yes, but it’s advisable to fix soon to prevent overheating or efficiency issues.
Will this fault come back after clearing?
It can if the underlying issue isn't fixed, like a bad sensor or wiring problem.
Why does this code pair with low coolant level?
Low coolant levels can cause incorrect readings from the temperature sensor, triggering this fault.
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