Engine Cooling System Temperature
Indicates a problem with engine coolant temperature reading.
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 gets a temperature reading from the coolant temperature sensor to monitor how hot the engine is running. If the reading is too high or low, it triggers this code because the engine might overheat or not run efficiently.
What the computer is actually seeing
The ECM sees the coolant temperature temperature as either too high (over 225°F) or too low (below 140°F) for a sustained period, indicating a malfunctioning sensor or a real problem with the cooling system.
What a healthy reading looks like
Expected coolant temp during normal operation is typically between 180°F and 220°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. Inspect the coolant level; ensure it is between the minimum and maximum marks.
- 22. Check the connector and wiring of the coolant temperature sensor for damage or corrosion.
- 33. Use a scanner to read the coolant temperature; it should match actual engine temp (use an infrared thermometer for verification). If it shows a constant value outside of expected range, suspect the sensor.
- 44. If the sensor's reading is erratic, check for wiring shorts or opens. Repair as needed.
- 55. If the sensor tests okay, check the thermostat for proper operation, ensuring it isn't stuck closed or open.
Common causes
- Faulty coolant temperature sensor
- Wiring issues in the sensor circuit
- Low coolant level
- Thermostat malfunction
- Cooling system leaks
Typical repair cost
$$
Related codes
Frequently asked questions
Is it safe to drive with this code?
It's not ideal, as overheating can occur; monitor temperatures closely and drive cautiously.
Will this code come back after clear?
If the issue persists (like a bad sensor), yes, it will return.
Why might this code appear alongside other codes?
Often, cooling system issues can manifest as multiple faults, especially when they affect the engine's operational safety.
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