What is SPN 191 FMI 9
- SPN 191: Refers to a fault in the engine coolant temperature sensor, indicating that the sensor is providing inaccurate or out-of-range temperature readings.
- FMI 9: Indicates that the signal from the coolant temperature sensor is invalid or out of range.
Together, SPN 191 FMI 9 signals that the engine coolant temperature sensor is not functioning correctly, potentially affecting the cooling system and engine performance.
Why It Happened
This fault is commonly caused by:
- Low coolant levels or coolant leaks.
- A malfunctioning coolant temperature sensor.
- Wiring issues or poor connections between the sensor and ECM.
- Contamination or debris in the coolant affecting sensor readings.
How to Resolve It
To resolve SPN 191 FMI 9:
- Check the coolant level and top off if necessary.
- Inspect the coolant temperature sensor for faults and replace it if needed.
- Check the wiring for any signs of damage or corrosion.
- After repairs, clear the fault code and restart the engine.
How to Avoid Before It Happens
To prevent SPN 191 FMI 9:
- Regularly inspect the coolant system and monitor coolant levels.
- Ensure proper maintenance of the coolant temperature sensor and wiring.
- Use Clue to track coolant temperature data and receive early alerts on irregular readings.
