What is SPN 520342 & How to Solve It?

What is SPN 520342:

SPN 520342 is a generic fault code related to the Aftertreatment Control Module (ACM). It typically signals a communication or configuration issue within the aftertreatment system, which includes components like the Diesel Particulate Filter (DPF), Selective Catalytic Reduction (SCR), and DEF systems. This code often appears when the ACM fails to receive or transmit expected data to the Engine Control Module (ECM), impacting emissions control and potentially triggering a derate.

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Why This Happens

• Loss of communication between ACM and ECM.
  
• Faulty or outdated ACM software.
  
• Corrupted configuration or calibration file.
  
• Damaged wiring or poor ground connections.
  
• Control module hardware failure.
  
  

How to Fix It

1. Scan for any related fault codes and communication errors.
   
2. Inspect ACM wiring, connectors, and grounds for damage or corrosion.
   
3. Verify the ACM software and calibration match OEM specifications.
   
4. Reflash or reprogram the ACM if needed.
   
5. Replace the ACM if it fails diagnostics or cannot be updated.
   
   

How to Avoid It Before It Happens

• Keep ECM and ACM software up to date using OEM tools.
  
• Avoid interrupting power during software updates.
  
• Routinely inspect harnesses and module connectors for wear.
  
• Use proper diagnostic equipment to catch early communication faults.
  
• Follow OEM guidelines when replacing or programming any emission-related modules.
• Use Clue’s Preventive Maintenance to ensure regular inspections of the ACM wiring and software updates, keeping the aftertreatment system running optimally.