What is SPN 1485 & How to Solve It?

What is SPN 1485:

SPN 1485 refers to the Aftertreatment DPF Differential Pressure — this code without an FMI generally signals a general malfunction in measuring pressure across the DPF.

It’s a critical parameter for triggering and validating regen cycles, and failure can result in over-sooting and performance reduction.

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Why This Happens

• Clogged or broken pressure sensor tubes.
  
• DPF pressure sensor beginning to fail.
  
• Leaking or cracked exhaust pre- or post-DPF.
  
• Electrical issue in sensor signal or reference.
  

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How to Fix It

1. Inspect and clean both sides of the DPF sensor tubes.
2. Test the sensor with diagnostics and compare to spec.
3. Replace the sensor if pressure readings are unstable.
4. Check for exhaust leaks around the sensor fittings.
5. Clear the fault and confirm successful regen trigger.
   

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How to Avoid It Before It Happens

1. Include tube cleaning in all PM inspections.
   
2. Replace sensors with drifting signals before failure.
   
3. Track regen intervals and pressure data routinely.
   
4. Watch for climbing soot loads outside normal schedule.