Detailed guide for SPN 110 FMI 2
Back to top ↑What SPN 110 FMI 2 means
SPN 110 identifies engine coolant temperature. FMI 2 indicates data that is erratic, intermittent or incorrect.
Detroit troubleshooting information describes this condition as coolant temperature outside the expected rational range or a temperature signal that has drifted high or low.
What to check first
Compare the coolant-temperature reading with engine oil temperature, ambient conditions and actual engine warm-up behavior.
Inspect the coolant-temperature sensor connector for corrosion, loose terminals or contamination. Check the harness for intermittent opens, shorts or damage.
Monitor live coolant-temperature data while the engine warms. An implausible jump, drop or value that does not track actual engine temperature can indicate a sensor or circuit problem.
Before replacing parts
Do not replace cooling-system components solely because of an FMI 2 fault. First determine whether the engine is actually overheating or whether the temperature signal itself is inaccurate.
Use OEM specifications because acceptable temperature differences and rationality limits vary between engine families.
Mechanic community notes for SPN 110 FMI 2
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