Description:

This diagnostic trouble code indicates that the supply pressure of the DEF dosing unit pump is unstable. This instability can affect the accurate dosing of DEF, leading to emissions control issues.

Reaction:

The ECU may limit or adjust the operation of the DEF dosing system to manage the unstable supply pressure and ensure safe operation of the emissions control system.

Recommendations:

• Inspect DEF Pump Wiring and Connections: Check for damaged, frayed, or loose wiring and connectors associated with the DEF dosing unit pump. Repair or replace as necessary.
• Test DEF Pump Function: Use diagnostic tools to test the DEF dosing unit pump for proper operation and consistent pressure build-up. Replace the pump if it is faulty.
• Check for Blockages: Inspect the DEF system for any blockages or restrictions that might cause pressure instability.
• Verify Electrical Supply: Ensure that the electrical supply to the DEF dosing unit pump is stable and within specifications.
• Monitor Operating Conditions: Review the operating conditions that might contribute to pressure instability, such as temperature fluctuations or contaminated DEF fluid.
• Reset ECU and Monitor System: After resolving the issue, reset the ECU to clear the fault code and monitor the system to ensure stable pump pressure and normal operation.

Note:

Proper operation of the DEF dosing unit pump is crucial for accurate DEF dosing and emissions control. Regular inspections and timely maintenance can help prevent pressure-related issues.