Engine Coolant Temperature Sensor Out of Range
The engine coolant temperature sensor (ECT) reading is abnormal.
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What it means (plain English)
The engine coolant temperature sensor measures how hot the engine coolant is. If the reading is too high or too low, it means there is a problem, which can lead to engine overheating or poor performance.
What the computer is actually seeing
The engine control module (ECM) is seeing a coolant temperature reading outside the expected range, usually below 30°C (86°F) or above 120°C (248°F).
What a healthy reading looks like
Typically, the coolant temperature should be between 85°C (185°F) and 105°C (221°F) when the engine is at operating temperature.
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 wiring and connectors for the coolant temperature sensor for any signs of damage or corrosion.
- 22. Measure the voltage at the coolant temperature sensor connector. Expect around 0.5V to 4.5V depending on coolant temperature.
- 33. If voltage is out of range, replace the coolant temperature sensor and retest.
- 44. If voltage is normal, check for coolant leaks around the sensor and inspect coolant level.
- 55. Check the engine thermostat operation; it should open within the normal operating temperature range.
Common causes
- Faulty coolant temperature sensor
- Wiring issues or poor connections
- Coolant leaks affecting temperature readings
- Faulty engine thermostat
Typical repair cost
$$
Related codes
Frequently asked questions
Is it safe to drive with this code?
It's recommended to fix this issue soon as it can lead to engine overheating, which can cause severe damage.
Will this issue come back after repair?
If the source of the problem is accurately identified and fixed, it should not return.
Why does this code sometimes appear with others?
This code often pairs with other codes related to temperature or engine performance, indicating a broader issue with engine cooling.
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