FMI 2 - Engine Coolant Temperature too High
Engine coolant temperature is exceeding the normal range.
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 control module (ECM) gets a signal from the coolant temperature sensor, and if it’s reading above 240°F (115°C) consistently, it triggers this code.
What the computer is actually seeing
The ECM sees coolant temperature readings that repeatedly exceed the set threshold of 240°F (115°C).
What a healthy reading looks like
Normal 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.
- 11. Check the coolant level in the reservoir; top off if low. Decision: If level is low, refill and monitor. If not low, proceed to step 2.
- 22. Inspect the coolant temperature sensor wiring and connector for damage or corrosion. Decision: If damaged, repair/replace wiring. If good, proceed to step 3.
- 33. Use a scan tool to check the actual coolant temperature reading. Compare with a known good temperature gauge. Decision: If readings are inconsistent, replace the sensor. If they match, proceed to step 4.
- 44. Check for proper operation of the thermostat. Verify that the engine reaches normal operating temperature. Decision: If it does not, replace the thermostat. If it does, check for blockages in the cooling system.
Common causes
- Coolant leak
- Thermostat stuck closed
- Faulty coolant temperature sensor
- Cooling system blockage
- Low coolant level
Typical repair cost
$$$
Related codes
Frequently asked questions
Is it safe to drive with this code?
No, driving with an overheating engine can cause serious damage.
Will this issue come back if I just clear the code?
Yes, if the underlying issue isn't fixed, the code will return.
Why is my check engine light on with this code?
The ECM is protecting the engine from overheating by alerting you to a temperature anomaly.
Working a real vehicle right now?
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