GOVERNOR GP 1799978 - Caterpillar

Table 1
J1939 Code and Description CDL Code and Description Comments
4334-15
Aftertreatment #1 DEF #1 Pressure (absolute) : High - least severity (1) E903 (1)
High Aftertreatment #1 DEF Pressure #1 The engine Electronic Control Module (ECM) detects that the DEF pump pressure is above the acceptable range.
The code is logged.
4334-16
Aftertreatment #1 DEF #1 Pressure (absolute) : High - moderate severity (2) E930 (2)
High Aftertreatment #1 DEF Pressure #1 The engine Electronic Control Module (ECM) detects that the DEF pump pressure is above the acceptable range.
The code is logged.
Table 2
Troubleshooting Test Steps Values Results
1. Check the Backflow Line for a Restriction
A. Turn the keyswitch to OFF. Allow 2 minutes to elapse before proceeding.
B. Remove the backflow line from the DEF header and the DEF pump.
C. Inspect the backflow line for obstructions. Flush line with water/low pressure air if necessary.
Note: Possible obstructions are ice, DEF deposits, or debris.
Restriction
Result: An obstruction was not found.
Proceed to Test Step 2.
Result: An obstruction was found.
Repair: Flush the line or replace the line.
Proceed to Test Step 4.
2. Replace the Backflow Fitting
A. Replace the backflow fitting on the DEF pump. Refer to the Disassembly and Assembly manual for the correct procedure.
Replace Backflow Fitting
Result: The fitting was replaced.
Proceed to Test Step 3.
3. Check for a Restriction in the DEF Pump
A. Reinstall the backflow line onto the DEF pump. Place the other end of the line into a bucket or beaker to collect the DEF.
B. Turn the keyswitch to ON. Do not start the engine.
C. Connect to the "Engine ECM" in Cat® Electronic Technician (ET).
D. Perform the "DEF Dosing System Verification Test". Refer to Troubleshooting, "Cat ET Service Features" for more information.
DEF Present
Result: DEF did not flow from the DEF backflow line into the container.
Repair: Replace the DEF pump and reinstall all DEF lines. Refer to the Disassembly and Assembly manual for the correct procedure.
Proceed to Test Step 4.
Result: DEF flowed from the backflow line into the container.
Repair: Reinstall the backflow line onto the DEF header.
Proceed to Test Step 4.
4. Perform a "Aftertreatment System Functional Test"
A. Start the engine.
B. Connect to the engine ECM in Cat ET.
C. Perform the "Aftertreatment System Functional Test".
"Aftertreatment System Functional Test"
Result: The test was successful.
Return the unit to service.
Result: The test was not successful. There are more codes.
Repair: Troubleshoot the additional codes. Refer to Troubleshooting for the correct procedure. Verify that the problem is resolved.
If the procedure did not correct the issue, contact your Cat dealer Technical Communicator (TC). For further assistance, your TC can confer with the Dealer Solutions Network (DSN).