Engine Coolant Temperature Above Normal Operating Range
The engine coolant temperature is higher than the normal range.
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What it means (plain English)
The coolant temperature sensor is reading high, which may indicate the engine is overheating.
What the computer is actually seeing
The ECU is reading a coolant temperature of 225°F (107°C) or above when it should be below 220°F (104°C).
What a healthy reading looks like
Normal operating range is 190°F to 220°F (88°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 coolant level. Low coolant can cause overheating. Fix any leaks and refill if needed.
- 22. Inspect the coolant temperature sensor connector and wiring for damage or corrosion. Repair as necessary.
- 33. Use a scan tool to read the actual coolant temperature and compare with the displayed value. If they differ significantly, the sensor is likely bad.
- 44. Check the operation of the thermostat. It should open at the specified temperature; if it’s stuck closed, replace it.
- 55. Assess the radiator for blockages (inside or outside). Ensure airflow is not obstructed. Clean if necessary.
- 66. If all previous steps check out, further investigate for internal engine issues that could be causing overheating.
Common causes
- Low coolant level
- Faulty coolant temperature sensor
- Failed thermostat
- Coolant leaks
- Clogged radiator
Typical repair cost
$$$
Related codes
Frequently asked questions
Is it safe to drive with this code?
No, it could lead to engine damage due to overheating.
Will this code come back after I repair it?
If the underlying issue is fixed (like the thermostat or coolant level), it should not return.
Why does this code sometimes appear with SPN 188?
SPN 188 indicates that the coolant temperature information is not valid or out of range, which can happen if the overheating condition affects sensor readings.
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