What is SPN 5842 FMI 14 & How to Solve It?

What is SPN 5842 FMI 14:

SPN 5842 FMI 14 indicates a problem with the Diesel Exhaust Fluid (DEF) Quality Sensor Circuit, usually a communication or signal fault. This sensor checks the quality of the DEF to ensure proper emissions reduction. When faulty, it can cause inaccurate readings, affecting emission controls.

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Why This Happens

Common causes include:

• Faulty DEF quality sensor.
  
• Damaged or corroded wiring or connectors.
  
• Contaminated or degraded DEF fluid.
  
• Sensor communication errors or calibration issues.

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How to Fix It

To fix this issue:

1. Inspect the DEF quality sensor and wiring for damage or corrosion.
   
2. Test sensor signals; replace the sensor if faulty.
   
3. Replace DEF fluid if contaminated.
   
4. Clear the fault and confirm proper system operation.

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How to Avoid It Before It Happens

Prevent this fault by:

• Using clean, quality DEF fluid.
  
• Regularly checking the sensor and wiring.
  
• Keeping the DEF system clean and maintained.
• Utilize Clue’s Equipment Tracking to monitor DEF quality sensor performance in real-time, catching issues early before they affect emissions control.