Cooling System Temperature Above Normal Operating Range
Indicates that the engine coolant temperature is too high.
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What it means (plain English)
The engine control module (ECM) is reading that the temperature of the coolant is above the normal operating range, typically around 220°F (104°C). When coolant reaches around 250°F (121°C), this code can be set, indicating potential overheating.
What the computer is actually seeing
The ECM monitors the engine coolant temperature via a sensor. When the sensor reports a temperature above the set threshold (commonly 250°F), the ECM triggers this fault code.
What a healthy reading looks like
Normal engine coolant temperature should be between 180°F and 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.
- 1Check coolant level in the reservoir and radiator. If low, refill and monitor for leaks—decision point: refilled? If yes, monitor; if no, investigate for leaks.
- 2Visually inspect the coolant temperature sensor and wiring for damage or corrosion. Repair as necessary—decision point: damaged? If yes, repair; if no, proceed to next step.
- 3Monitor the engine coolant temperature with a scan tool. Is it above 250°F (121°C) during operation?—decision point: overheat? If yes, investigate cooling system components; if no, potential sensor issue.
Common causes
- Low coolant level
- Cooling system leak
- Faulty coolant temperature sensor
- Failed water pump
- Clogged radiator
Typical repair cost
$$
Related codes
Frequently asked questions
Is it safe to drive with this code?
No, the vehicle should not be driven until the overheating issue is resolved to prevent serious engine damage.
Will this code come back?
If the underlying issue causing the overheating is not fixed, this code will likely return.
Why does this code pair with others?
Codes related to coolant functioning, such as low coolant or sensor issues, can occur simultaneously if there's a systemic cooling problem.
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