SPN 110 — Engine Coolant Temperature
System: Cooling
Temperature of the engine coolant, usually measured near the thermostat housing.
Can I keep running it?
STOP — shut down if the condition is real
If the engine is truly overheating, stop and let it cool. Never open a hot radiator cap.
Likely causes
- Low coolant level or leak
- Stuck thermostat
- Fan clutch or fan drive not engaging
- Plugged radiator or debris on the cooling stack
- Failed water pump
- Sensor or wiring fault
Checks & fixes (easiest first)
- Check coolant level (engine cool)
- Clean debris from radiator and coolers
- Verify fan engagement
- Compare sensor reading to an infrared thermometer
- Pressure-test the cooling system
Common FMIs with SPN 110
- SPN 110 FMI 0Value too high (most severe)
- SPN 110 FMI 2Data erratic, intermittent, or incorrect
- SPN 110 FMI 3Voltage above normal or shorted high
- SPN 110 FMI 4Voltage below normal or shorted low
- SPN 110 FMI 15Value too high (least severe)
- SPN 110 FMI 16Value too high (moderately severe)
- SPN 110 FMI 17Value too low (least severe)
Related codes
FAQ
What does SPN 110 mean?
SPN 110 is Engine Coolant Temperature. Temperature of the engine coolant, usually measured near the thermostat housing.
Can I keep running with SPN 110?
If the engine is truly overheating, stop and let it cool. Never open a hot radiator cap.
What causes SPN 110?
Low coolant level or leak; Stuck thermostat; Fan clutch or fan drive not engaging; Plugged radiator or debris on the cooling stack; Failed water pump; Sensor or wiring fault.