What is SPN 157 FMI 10 & How to Solve It?

What is SPN 157 FMI 10:

SPN 157 FMI 10 refers to a high voltage condition in the Coolant Temperature Sensor Circuit. FMI 10 indicates that the ECM is receiving a voltage higher than expected, which can lead to incorrect temperature readings and potentially cause the engine to overheat.

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Why This Happens:

• Faulty coolant temperature sensor.
  
• Shorted or damaged wiring in the sensor circuit.
  
• High voltage supply affecting the sensor’s output.
  
• Loose or corroded sensor connectors.
  
• ECM misinterpreting the sensor data.
  
  

How to Fix It:

1. Inspect the coolant temperature sensor for visible damage.
   
2. Test the sensor’s signal to ensure it is within the expected range.
   
3. Check wiring and connectors for visible damage, corrosion, or loose connections.
   
4. Replace the faulty sensor if necessary.
   
5. Ensure proper voltage regulation and check the ECM for proper signal interpretation.
   
   

How to Avoid It Before It Happens:

• Regularly inspect the coolant temperature sensor and its wiring.
  
• Maintain proper coolant levels and replace coolant as needed.
  
• Keep connectors clean and free from corrosion.
  
• Perform routine diagnostic checks to monitor sensor performance.
  
• Clue’s Equipment Maintenance services help ensure coolant systems and sensors are functioning optimally, preventing issues before they affect engine health.