What is SPN 102 FMI 4:
SPN 102 FMI 4 refers to a fault in the Engine Coolant Temperature Sensor Circuit. FMI 4 indicates that the ECM is receiving an out-of-range voltage from the sensor, which can lead to engine mismanagement, poor performance, and potential overheating.
Why This Happens:
- Faulty coolant temperature sensor.
- Damaged or shorted wiring in the sensor circuit.
- Corroded or loose sensor connectors.
- Low coolant levels affecting the sensor’s ability to measure temperature accurately.
- ECM failure to interpret the sensor’s data.
How to Fix It:
- Inspect the coolant temperature sensor for visible damage or wear.
- Test the sensor’s voltage and resistance to ensure it falls within manufacturer specifications.
- Check the wiring and connectors for damage or corrosion.
- Replace the faulty coolant temperature sensor if necessary.
- Ensure that coolant levels are correct and that the cooling system is functioning.
How to Avoid It Before It Happens:
- Regularly inspect the coolant system and sensors for damage or wear.
- Keep connectors clean and free from moisture and corrosion.
- Ensure coolant levels are maintained and the system is regularly serviced.
- Use diagnostic tools to monitor sensor accuracy and coolant system performance.
- Clue’s Equipment Maintenance services help monitor coolant system health and prevent potential issues before they lead to engine overheating or damage.
