What is SPN 3936 FMI 18 & How to Solve It?

What is SPN 3936 FMI 18

• SPN 3936: Refers to a fault in the exhaust gas recirculation (EGR) flow rate sensor.
  
• FMI 18: Indicates that the sensor is reporting a value higher than expected, meaning the flow rate reading is too high.
  

Together, SPN 3936 FMI 18 signals a problem with the EGR flow rate sensor, indicating that the EGR flow is higher than expected, which could affect engine performance and emissions.

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Why It Happened

This fault code is typically caused by:

• A malfunctioning or faulty EGR flow rate sensor.
  
• A failure in the EGR valve or system causing excessive flow.
  
• Wiring issues or poor connections between the sensor and ECM.
  
• Contamination or blockages in the EGR system affecting sensor readings.
  
  

How to Resolve It

To resolve SPN 3936 FMI 18:

1. Inspect the EGR flow rate sensor and replace it if necessary.
   
2. Check the EGR system for excessive flow, blockages, or contamination.
   
3. Inspect the wiring and connections for damage or corrosion.
   
4. After repairs, clear the fault code and restart the engine.

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How to Avoid Before It Happens

To prevent SPN 3936 FMI 18:

• Regularly inspect the EGR system and sensor for proper function.
  
• Clean the EGR valve and check for blockages or contamination.
  
• Use Clue to monitor EGR system data in real-time and catch issues early.