What is SPN 641 FMI 14 & How to Solve It?

What is SPN 641 FMI 14:

SPN 641 FMI 14 indicates a low voltage issue in the Exhaust Gas Temperature (EGT) Sensor Circuit. FMI 14 suggests that the sensor is sending a lower than expected signal to the ECM, which can lead to incorrect exhaust temperature readings and impact the exhaust after-treatment system.

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Why This Happens:

• Faulty exhaust gas temperature sensor.
  
• Damaged or shorted wiring in the sensor circuit.
  
• Loose or corroded sensor connectors.
  
• Blocked or malfunctioning exhaust system.
  
• ECM misinterpretation of the sensor’s signal.
  
  

How to Fix It:

1. Inspect the exhaust gas temperature sensor for damage or malfunction.
   
2. Test the sensor’s signal to verify it is within specifications.
   
3. Check wiring and connectors for visible damage or corrosion.
   
4. Replace the faulty sensor if necessary.
   
5. Inspect the exhaust system for blockages or contamination.
   
   

How to Avoid It Before It Happens:

• Regularly inspect the exhaust gas temperature sensor and wiring.
  
• Keep connectors clean and free from debris or corrosion.
  
• Perform routine exhaust system checks to ensure optimal performance.
  
• Monitor EGT sensor health with diagnostic tools.
  
• Clue’s Equipment Maintenance services ensure EGT sensors and exhaust systems are performing optimally, preventing issues before they arise.