Engine Coolant Temperature Above Normal Operating Range
The engine coolant temperature is too high for normal operation.
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What it means (plain English)
The engine computer monitors the coolant temperature, and if it senses a temperature above the normal range (usually over 230°F or 110°C), it will trigger this code to prevent engine damage.
What the computer is actually seeing
The ECM sees a coolant temperature reading that exceeds predetermined limits; if it stays above this limit for too long, it sets the fault code.
What a healthy reading looks like
Normal coolant temperature is typically between 190°F to 220°F (88°C to 104°C). Above 230°F (110°C) triggers code.
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 in the reservoir and system. Top off if low and monitor. If good, proceed.
- 22. Inspect for coolant leaks around hoses, the radiator, and engine. Repair any leaks found.
- 33. Measure the temperature at the outlet of the thermostat using a digital thermometer; compare with ECM readings. This confirms if the sensor is faulty.
- 44. Check the radiator fan operation; the fan should engage when temperatures exceed 230°F (110°C). If not, check wiring and relay.
- 55. If all preceding checks are normal, replace the thermostat and flush the cooling system.
Common causes
- Low coolant level
- Failed thermostat
- Cooling system leak
- Inoperative radiator fan
- Faulty temperature sensor
Typical repair cost
$$$
Related codes
Frequently asked questions
Is it safe to drive with this code?
No, this can lead to engine damage or overheating, so fix immediately.
Will this code return after clearing?
Yes, if the underlying issue isn't fixed, the code will likely return.
Why does this code sometimes appear with SPN 110?
SPN 110 concerns engine overheating. If the engine runs too hot, both codes may trigger.
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