Engine Coolant Temperature Above Normal Operating Range
The engine coolant temperature is too high for proper operation.
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 detects that the coolant is running hotter than it should, usually over about 220°F (104°C).
What the computer is actually seeing
The Engine Control Unit (ECU) sees a coolant temperature reading over the threshold set, indicating a potential overheating situation.
What a healthy reading looks like
Expected coolant temperature readings should be between 180°F (82°C) and 220°F (104°C) under normal operating conditions.
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 in the reservoir and radiator. Make sure it’s full. If low, refill and check for leaks.
- 22. Inspect hoses and connections for any signs of leakage or damage.
- 33. Test the coolant temperature sensor with a multimeter: expected resistance should be around 2000 ohms at 80°C (176°F).
- 44. Check the thermostat operation: when heated in water, it should open at approximately 195°F (91°C). If it doesn’t, replace it.
- 55. Verify that the water pump is circulating coolant effectively and there are no blockages in the cooling system.
Common causes
- Low coolant level
- Coolant leak in the system
- Faulty thermostat
- Failed water pump
- Blocked radiator or faulty fan operation
Typical repair cost
$$
Related codes
Frequently asked questions
Is it safe to drive with this code?
It can lead to engine overheating, so fix it soon to avoid serious damage.
Will this issue come back after fixing?
If the root cause (like a leak or defective component) isn't addressed, it likely will.
Why does this code sometimes pair with SPN 1009?
SPN 1009 relates to the engine oil temperature, and both overheating symptoms can be related to coolant issues.
Working a real vehicle right now?
Let DiagCoach walk you through it live with your specific symptoms, vehicle, and what you've already checked.
Start guided diagnostic →