Engine Coolant Temperature Sensor Out of Range
The engine's coolant temperature sensor reading is outside the expected range.
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What it means (plain English)
The coolant temperature sensor measures how hot the engine coolant is. If it’s reading too high or too low, it could indicate a problem with the sensor or the cooling system itself.
What the computer is actually seeing
The engine control module (ECM) expects the coolant temperature to be between 180°F and 220°F (82°C to 104°C) during normal operation. If the sensor reports a temperature lower than 150°F (65°C) or higher than 250°F (121°C), it triggers this code.
What a healthy reading looks like
Normal operational range is 180°F to 220°F (82°C to 104°C). If below 150°F (65°C) or above 250°F (121°C), it's considered out of range.
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 coolant level in the reservoir. Fill if low. Decision: Is the fluid level good? (Yes / No)
- 22. Inspect wiring and connectors at the coolant temperature sensor for damage or corrosion. Decision: Are connections secure and intact? (Yes / No)
- 33. Use a scan tool to monitor the actual coolant temperature while the engine is running. Decision: Is the reading within expected normal range? (Yes / No)
- 44. If readings are incorrect, test the coolant temperature sensor with an ohmmeter for resistance consistency. Consult manufacturer specifications for resistance values at specific temperatures. Decision: Is the sensor functioning correctly? (Yes / No)
- 55. If the sensor is faulty, replace it, but also check for potential issues with the ECM if the problem persists.
Common causes
- Faulty coolant temperature sensor
- Wiring issues or damaged connectors
- Low coolant level or coolant leaks
- Bad ECM calibration or fault
Typical repair cost
$$
Related codes
Frequently asked questions
Is it safe to drive with this code?
Moderate severity means you can drive, but monitor temperature closely. Don't ignore it for long.
Will this code come back after repairs?
If fixed properly, it shouldn't return unless there's another underlying issue.
Why does this code often pair with SPN 1001?
SPN 1001 indicates a problem with the coolant temperature sensor circuit, often tied to SPN 3012.
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