AdBlue/DEF systems are essential for modern diesel engines, but they often experience faults that lead to machine downtime, increased maintenance costs, and performance issues. This guide covers the most common DEF system problems and how to troubleshoot them effectively.

Common AdBlue/DEF System Faults and Solutions

1. DEF Warning Light Staying On

Possible Causes:

  • DEF fluid is low or contaminated.
  • DEF sensor malfunction.
  • Blocked or frozen DEF injector.

Solution:

  • Refill with fresh, high-quality DEF fluid.
  • Check and clean the DEF injector.
  • Inspect sensor wiring and replace faulty components if necessary.

2. Engine Power Reduction (Limp Mode)

Possible Causes:

  • DEF system failure detected by ECU.
  • Faulty SCR catalyst.
  • DEF pump or injector blockage.

Solution:

  • Perform a system scan using diagnostic tools.
  • Clean or replace the SCR catalyst if clogged.
  • Ensure the DEF pump is functioning properly and free of blockages.

3. DEF Crystallization in the System

Possible Causes:

  • DEF fluid has evaporated and left crystallized deposits.
  • The DEF injector is clogged due to deposits.
  • Temperature fluctuations causing fluid breakdown.

Solution:

  • Flush the system with warm water (do not use chemicals).
  • Regularly inspect and clean the DEF injector.
  • Store DEF fluid at optimal temperatures (between -11°C and 30°C).

4. DEF Pump Failure

Possible Causes:

  • Clogged or contaminated DEF fluid.
  • DEF filter is blocked.
  • Electrical issues with the pump.

Solution:

  • Replace DEF filters regularly to prevent clogging.
  • Check electrical connections and fuses related to the pump.
  • Flush the DEF tank and refill with fresh DEF fluid.

5. SCR Efficiency Below Threshold

Possible Causes:

  • DEF quality is poor.
  • SCR catalyst is degraded.
  • DEF dosing system malfunction.

Solution:

  • Use only high-quality DEF that meets ISO 22241 standards.
  • Replace the SCR catalyst if it shows signs of wear.
  • Test and calibrate the DEF dosing system.

How a DEF Delete Emulator Can Help

If your construction machine is experiencing recurring DEF system failures, a DEF Delete Emulator can bypass these faults and prevent costly downtime. These emulators mimic a functional DEF system, ensuring uninterrupted performance. Learn more about when and how to safely disable the DEF system in our full guide.

Final Tips for DEF System Maintenance

  • Always use high-quality DEF fluid to avoid contamination issues.
  • Regularly inspect and clean DEF components such as injectors, pumps, and filters.
  • Keep the system’s software updated to prevent compatibility issues.
  • Consider a DEF Delete Emulator if your machine operates in a non-regulated area.

Need Assistance? Contact Us!

If you’re struggling with DEF system issues, our team is here to help. Get in touch for expert troubleshooting and solutions.

This troubleshooting guide ensures that machine operators can identify and resolve common DEF system issues quickly.

Still troubleshooting issues? Our DEF Delete Emulator guide may offer a long-term solution.

Similar Posts