Engine Cooling System Temperature Too High
The engine is overheating or has low coolant levels.
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)
When the engine temperature sensor detects the coolant temperature above the normal operating limits, the warning is triggered. Normally, the engine should run at about 190°F to 220°F. If it goes beyond 240°F, the alert is set to warn about potential overheating.
What the computer is actually seeing
The ECU is monitoring the temperature signal from the coolant temperature sensor. If the temperature reading goes over 240°F for more than 2 seconds, the code is triggered.
What a healthy reading looks like
Normal coolant temperature ranges from 190°F to 220°F; values exceeding 240°F are problematic.
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. If it's low, fill it to the specified level. Decision: If it was low, top off and retest; if not, proceed to step 2.
- 22. Inspect for visible coolant leaks in hoses, radiator, and engine area. Decision: If leaks are found, fix them and refill coolant; if no leaks, proceed to step 3.
- 33. Test the coolant temperature sensor by measuring resistance (should be around 2.5 kΩ at 200°F). If out of spec, replace the sensor and retest; if within spec, proceed to step 4.
- 44. Check the operation of the thermostat by observing the engine temperature during operation. Should open at around 195°F. If it doesn't, replace the thermostat; if it operates correctly, proceed to step 5.
- 55. Inspect the cooling fan operation. When the temp exceeds 220°F, the fan should activate. If it doesn't, test the fan; if the fan is faulty, replace it and retest.
Common causes
- Low coolant level
- Coolant leak
- Faulty coolant temperature sensor
- Thermostat stuck closed
- Cooling fan not operating properly
Typical repair cost
$$$
Related codes
Frequently asked questions
Is it safe to drive with this code active?
No, driving with an overheating engine can cause severe engine damage.
Will this code come back if the issue is fixed?
If the underlying issue is resolved, the code should not return.
Why do I see this code alongside SPN 1334?
Both codes relate to cooling system problems, often triggered under the same conditions.
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