Engine Over Temperature
The engine coolant temperature exceeds the normal operating range.
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 computer is saying the engine is running too hot. This could happen if the coolant is low, the thermostat is stuck, or the water pump isn't working right.
What the computer is actually seeing
The engine control module (ECM) measures coolant temperature from the sensor, typically in degrees Fahrenheit or Celsius. If it reads above 240°F (115°C) for a set duration, it triggers this code.
What a healthy reading looks like
Normal coolant temperature should be between 180°F to 220°F (82°C to 104°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 proper mark. If low, fill it and see if the code reappears.
- 22. Inspect the coolant temperature sensor connector and wiring for damage. Repair if necessary.
- 33. Test the coolant temperature sensor with a multimeter; it should output 0.5V - 4.5V based on temperature. Replace if out of spec.
- 44. Check the thermostat operation by starting a cold engine and seeing if the upper radiator hose warms up within 10-15 minutes; if not, replace the thermostat.
- 55. Inspect the water pump for leaks or failure; the pump should circulate coolant properly with no strange noises. Replace if defective.
- 66. Ensure the cooling fan operates when the engine reaches normal temperature; if it does not, test the fan and its relay.
Common causes
- Low coolant level
- Thermostat failure
- Water pump failure
- Cooling fan not operating
- Clogged radiator
- Blocked coolant passages
Typical repair cost
$$
Related codes
Frequently asked questions
Is it safe to drive with this code?
No, driving with an over-temperature condition can damage the engine.
Will the code come back if I clear it?
It may come back if the underlying issue isn't fixed.
Why does this code sometimes pair with other codes?
Other codes may appear if there are related issues, like cooling system faults.
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