Engine Coolant Temperature Out of Range
The engine's coolant temperature is reading too high or too low.
Heads up: this code wasn't in our hand-written library yet, so DiagCoach AI built this page on the fly. Double-check critical specs against service info before condemning parts.
What it means (plain English)
The engine's computer is seeing a coolant temperature that's either way too hot or too cold—like over 250°F or below 150°F. This can confuse the engine about how to run properly.
What the computer is actually seeing
The ECM (Engine Control Module) receives coolant temperature data from the sensor, which should normally fluctuate between 170°F and 210°F. If the reading is above 250°F or below 150°F, it will trigger this fault code.
What a healthy reading looks like
Coolant temperature should be between 170°F and 210°F (77°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; it should be at the recommended level in the reservoir. Decision: If low, top it off and retest. If full, continue.
- 22. Inspect the wiring and connectors for the coolant temperature sensor. Look for frays, corrosion, or loose connections. Decision: Repair any issues found, then retest.
- 33. Use a scan tool to monitor the coolant temperature; compare the reading to the ambient temperature. Decision: If the reading is drastically off (above 250°F or below 150°F), replace the coolant temperature sensor.
- 44. Check the thermostat operation. Start the engine and observe the temperature rise; it should reach operating temperature gradually. Decision: If it doesn't, replace the thermostat and retest.
Common causes
- Faulty coolant temperature sensor
- Wiring issues (shorts/open circuits)
- Coolant level low
- Thermostat stuck open/closed
Typical repair cost
$$
Related codes
Frequently asked questions
Is it safe to drive with this code?
Moderately safe, but keep an eye on engine temperature; avoiding overheating is crucial.
Will this code come back after clearing?
If the underlying issue isn't fixed, yes, it will return.
Why do I see this with other codes?
Related codes often indicate the same condition affecting the engine's cooling system.
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