Engine Temperature Sensor Out of Range
Engine coolant temperature sensor reading is outside of expected range.
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What it means (plain English)
The engine temperature sensor is measuring the coolant temperature incorrectly, indicating your engine might be too hot or too cold.
What the computer is actually seeing
The engine control module (ECM) sees a coolant temperature reading that is outside the range of -40°C to 125°C (-40°F to 257°F).
What a healthy reading looks like
Coolant temperature should be between 80°C and 100°C (176°F to 212°F) under normal operating conditions.
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. If low, top it off and recheck symptoms. Decision: If coolant was low, monitor system for leaks. If not low, proceed.
- 22. Inspect wiring and connectors for damage at the engine coolant temperature sensor. Decision: If damaged, repair/replace. If not damaged, proceed.
- 33. Test the engine coolant temperature sensor with a multimeter. Expected resistance should be around 2.5k ohms at 20°C (68°F). Decision: If out of range, replace the sensor. If within range, proceed.
- 44. Clear the fault code and run the engine to see if the code returns. Decision: If it returns, further investigate potential wiring issues or replace the ECM.
Common causes
- Faulty engine coolant temperature sensor
- Wiring issues or damaged connectors
- Coolant leaks affecting sensor readings
Typical repair cost
$$
Related codes
Frequently asked questions
Can I still drive with this code?
Yes, but monitor engine temperature closely to avoid overheating.
Will this code come back after clearing?
It might if there's an underlying issue with the sensor or wiring.
Why does this code pair with SPN 1901?
SPN 1901 indicates sensor performance issues, which often go hand-in-hand with SPN 1902.
Working a real vehicle right now?
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