Coolant Temperature Sensor Circuit Out of Range
The coolant temperature sensor is reporting a temperature outside of the expected range.
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What it means (plain English)
The engine's computer sees that the coolant temperature is either too low or too high, which means the engine might not be running at the right temperature.
What the computer is actually seeing
The ECM (Engine Control Module) expects the coolant temperature to be between 185°F and 210°F (85°C to 99°C) during normal operation. Values outside this range trigger the fault code.
What a healthy reading looks like
Coolant temperatures should typically range from 185°F to 210°F (85°C to 99°C).
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. Add coolant if needed, and inspect for leaks. If low, fill and test drive to see if the code returns.
- 22. Inspect the wiring and connectors at the coolant temperature sensor for damage or corrosion. Repair any found issues and retest.
- 33. Use a scan tool to check the live data of the coolant temperature sensor. Compare the reading with an external thermometer to see if it's accurate.
- 44. If the sensor reading is still out of range during normal operating conditions, replace the coolant temperature sensor.
- 55. Clear codes and test drive the vehicle to check for reappearance.
Common causes
- Faulty coolant temperature sensor
- Wiring issues or corrosion in connections
- Coolant leaks or low coolant level
- Engine overheating due to external factors
Typical repair cost
$$
Related codes
Frequently asked questions
Is it safe to drive with this code?
It's okay for short distances, but fix it soon to avoid overheating or inefficiencies.
Will this code come back after clearing it?
It can return if the underlying issue isn't addressed, like a bad sensor or wiring.
Why does it pair with other SPNs?
Codes like SPN 4444 may relate to the same sensor or circuit, indicating a shared issue.
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