CONTROL GP-STEERING 2591644 - Caterpillar

Illustration 14 g01384472
Trip line for a check valve that is stuck
A stuck check valve can cause the purge pressure to be below trip line (B).
Refer to Illustration 14. Identify your barometric pressure on the chart. Compare the pressure readings to the trip line on the chart. Expected Result:The pilot pressure or the main pressure was below the trip line.Results:
No - Both pressures were above the trip line. One cleaning solved the problem. Proceed to Test Step 9.
Yes - The pilot pressure or the main pressure was below the trip line. Cleaning the check valves did not solve the problem.Repair: The ARD combustion head must be replaced. Perform the following steps in order to replace the ARD combustion head:Note: The fuel system must be flushed and the connector filters must be replaced before installing a new ARD head.Note: There is a third connector filter that needs to be replaced in a system that has an ARD purge air pump. The third connector filter is also located in the manifold for the lines to the ARD head. The filter is for ARD purge air to the ARD head.
Illustration 15 g01731615
Fuel lines on the ARD combustion head
Illustration 16 g01731617
The connector filters are located in the manifold for the lines to the ARD head.
(26) Location of the connector filters on C15 applications
(27) Location of the connector filters on certain C13 applications
Flush the fuel system and replace the connector filters exactly as instructed in the Special Instruction, REHS3848, "Procedure to Flush the Fuel System for the Aftertreatment Regeneration Device (ARD)". Refer to illustration 15 and illustration 16.
Install a new ARD head. Ensure that all electrical connections are connected. Ensure that all fuel connections are connected. Use the correct torque on all fuel line fittings.
You must check the fuel lines for leaks after the ARD combustion head and the connectors are installed. Refer to Special Instruction, REHS3412, "Inspecting the Fuel System for the Aftertreatment Regeneration Device". Proceed to Test Step 9.Test Step 8. Isolate the Problem
Turn the keyswitch to the off position. Clear the 3490-6 diagnostic trouble code.
Disconnect the 4-pin connectors for the pump.
Turn the keyswitch to the on position. The ECM will send a command signal to the pump after a 15 second delay.
Look for an active 3490-6 diagnostic trouble code after the 15 second delay. Expected Result:A 3490-6 diagnostic trouble code becomes active.Results:
Yes -