What is SPN 157 FMI 15 & How to Solve It?

What is SPN 157 FMI 15:

SPN 157 FMI 15 refers to a high voltage issue in the Engine Coolant Temperature Sensor Circuit. FMI 15 indicates that the coolant temperature sensor is sending a voltage signal higher than expected, which can cause overheating or engine mismanagement.

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Why This Happens:

• Faulty coolant temperature sensor.
  
• Damaged or shorted wiring in the sensor circuit.
  
• Corroded or loose sensor connectors.
  
• ECM misinterpretation of the sensor signal.
  
• Low coolant levels causing sensor malfunction.
  
  

How to Fix It:

1. Inspect the coolant temperature sensor for visible damage or wear.
   
2. Test the sensor to ensure the voltage and resistance fall within manufacturer specifications.
   
3. Check wiring and connectors for damage or corrosion.
   
4. Replace the faulty sensor if necessary.
   
5. Ensure proper coolant levels and check the cooling system.
   
   

How to Avoid It Before It Happens:

• Regularly inspect the coolant temperature sensor and wiring.
  
• Keep connectors clean and free from corrosion.
  
• Maintain proper coolant levels and replace coolant as needed.
  
• Perform routine diagnostic checks to monitor sensor accuracy.
  
• Clue’s Equipment Maintenance services help track coolant temperature sensors and prevent potential issues before they cause engine overheating.