Engine Coolant Temperature Sensor
The engine coolant temperature is out of range.
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What it means (plain English)
Your engine coolant temperature sensor is reporting a temperature that's too high or too low, which can lead to overheating or inefficient engine performance.
What the computer is actually seeing
The Engine Control Module (ECM) is monitoring the engine coolant temperature through a sensor that should normally read between 180°F and 220°F when the engine is at operating temperature. If it reads outside this range, a fault code is triggered.
What a healthy reading looks like
Normal readings should range between 180°F to 220°F; sensor resistance should be consistent with these temperatures (approximately 2,000-3,000 ohms at 180°F).
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 — should be above the minimum mark. If low, top it off and recheck code after a short drive. Decision: If code returns, proceed to next step; if not, fix leaks.
- 22. Inspect wires and connectors at the coolant temperature sensor for damage or corrosion. Decision: If damaged, repair or replace wiring; check code again.
- 33. Use a scan tool to monitor the coolant temperature while the engine runs at operating temperature. It should show between 180°F and 220°F. Decision: If reading is out of range, replace the coolant temperature sensor; if in range, investigate further for temperature sensor circuit issues.
Common causes
- Failed coolant temperature sensor
- Wiring issue (broken or shorted wire)
- Poor connector contact
- Low coolant level
- Cooling system leaks
Typical repair cost
$$
Related codes
Frequently asked questions
Is it safe to drive with this code?
It's moderate severity; you can drive but should fix it soon to avoid overheating or performance issues.
Will this problem come back after repairs?
If wiring and the sensor are replaced properly and there's no coolant issue, it shouldn't come back.
Why do I see this code if the engine seems to run fine?
The ECM still needs accurate data to optimize performance and prevent engine damage, even if you don't notice immediate issues.
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