FMI 2 - Engine Coolant Temperature Above Normal Operating Range

The engine computer is sensing that the coolant temperature is higher than normal, which usually indicates overheating or a malfunctioning cooling system.

The engine control module (ECM) receives voltage signals from the coolant temperature sensor (CTS). A normal operating temperature typically ranges from 180°F to 220°F. If the signal indicates temperatures above 240°F, this code triggers.

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.

1. 11. Check the coolant level; top off if low. Decision: If coolant level is normal, proceed to step 2.
2. 22. Inspect wiring and connectors to the coolant temperature sensor for damage or corrosion. Decision: If wiring is intact, proceed to step 3.
3. 33. Use a scan tool to read the current coolant temperature; compare with a handheld infrared thermometer. Decision: If significant discrepancy exists, replace sensor. If readings are similar, proceed to step 4.
4. 44. Test the thermostat operation: ensure it opens at the correct temperature. Decision: If stuck closed, replace thermostat. If operational, proceed to step 5.
5. 55. Check the operation of the cooling fan; it should engage at high temperatures. Decision: If the fan is not working, repair or replace fan assembly.

• Failed coolant temperature sensor
• Low coolant level
• Blocked radiator or cooling system
• Failed thermostat
• Cooling fan not operating

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