Detailed guide for SPN 110 FMI 4
Back to top ↑What SPN 110 FMI 4 means
SPN 110 identifies engine coolant outlet temperature.
FMI 4 indicates sensor voltage below normal or a circuit shorted toward a low source.
Detroit documentation describes SPN 110 FMI 4 as an engine coolant outlet temperature circuit failed-low condition.
What you may notice
The malfunction indicator lamp and check-engine light may illuminate.
The electronic coolant-temperature value may appear unrealistically low or may not represent actual engine temperature.
What to check first
Inspect the coolant-temperature sensor wiring for chafing, damaged insulation or a short to ground.
Check the connector for corrosion, bent terminals or poor contact.
Verify the sensor supply, ground and signal circuit using the OEM wiring diagram.
Important
This is primarily an electrical sensor-circuit fault. Do not replace thermostats, radiators or other cooling-system components until actual coolant temperature and sensor-circuit operation have been verified.
Mechanic community notes for SPN 110 FMI 4
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