LINES GP-AUXILIARY HYDRAULIC 1538819 - Caterpillar

Introduction
The problem that is identified below does not have a known permanent solution. Until a permanent solution is known, use the solution that is identified below.Problem
The in-line fuel filters for the Aftertreatment Regeneration Device (ARD) can become plugged. The plugging of the in-line filters can cause issues with regeneration that can result in a "3711-31 Insufficient temperature to regenerate", "3474-31 Loss of combustion", "3473-31 Failure to ignite", and "3556-7 nozzle not responding" codes. The sources of debris that can plug the filters can be from the following: factory assembly, component replacement in the field and repair procedures.Solution
The new procedure for flushing the fuel system must be followed when replacing the ARD combustion head or one of the fuel control valves on Caterpillar truck engines that are equipped with an Aftertreatment Regeneration Device.
It is critical to the system that NO lubricant is used on the filter fittings threads. There have been instances of these fuel filters plugging from technicians using anti-seize on the threads.
When troubleshooting leads to replacing the ARD head for the codes mentioned above and the amperage is correct for the heated nozzle, proceed to the following steps:
Perform the procedure to flush the fuel system. Refer to Special Instruction, REHS3848, "Procedure to Flush the Fuel System for the Aftertreatment Regeneration Device (ARD)" for the proper procedure.
Replace the fittings that contain the in-line fuel filters.
Perform a stationary regeneration in order to test the system after a repair.
If the new in-line fuel filters did not repair the engine then the ARD head can be replaced. Do not replace the in-line fuel filters again.When troubleshooting leads to replacing the pilot or main fuel control valves for the codes mentioned above and the amperage is correct for the heated nozzle, proceed to the following steps:
Replace the control valve.
Perform the procedure to flush the fuel system. Refer to Special Instruction, REHS3848, "Procedure to Flush the Fuel System for the Aftertreatment Regeneration Device (ARD)" for the proper procedure.
Replace in-line fuel filters.
Perform a regeneration after the repair in order to test the system.Note: The in-line fuel filters are being recalled so the filters should be handled properly.