CORE ASSEM. 6N9218 - Caterpillar

Table 1
J1939 Code and Description CDL Code and Description Comments
4334–7
Aftertreatment 1 Diesel Exhaust Fluid Doser Absolute Pressure: Not Responding Properly 3090–7
Aftertreatment 1 Diesel Exhaust Fluid Doser Absolute Pressure: Not Responding Properly DEF pump pressure is not stable after the initial priming sequence or the DEF pump is not able to supply DEF after the line heaters have been energized and a heating cycle has been completed.
4334-18
Aftertreatment #1 DEF Doser absolute Pressure Low - moderate severity (2) E931(1)
Aftertreatment #1 DEF Doser absolute Pressure Low - moderate severity (2) Diesel Exhaust Fluid (DEF) system pressure dropped below the acceptable threshold during dosing
5392–31
Aftertreatment Diesel Exhaust Fluid Dosing Unit Loss of Prime E1370(1)
Aftertreatment Diesel Exhaust Fluid Dosing Unit Loss of Prime Diesel Exhaust Fluid (DEF) system pressure was not achieved during priming Reference: Refer to the Disassembly and Assembly for the appropriate procedure for the removal and installation of components.
Table 2
Troubleshooting Test Steps Values Results
1. Check the Diesel Exhaust Fluid (DEF) Tank Filler Cap.
A. Clean dirt and debris from around the tank cap before removing the cap. Blockages can be caused by a build-up of dirt and debris around the cap.
Note : A blocked DEF filler cap can cause a code.
B. Remove and inspect the filler cap for blockages.
DEF Filler Cap
Result : A blockage was not found.
Proceed to Test Step 2.
Result : A blockage was found.
Repair : Rinse the cap gently with clean water or replace the cap. The cap contains a membrane so care must be taken not to damage the membrane. If the cap cannot be cleaned, replace the cap.
Proceed to Test Step 2.
2. Check the Diesel Exhaust Fluid (DEF) Gauge.
A. Turn the keyswitch to ON. Do not start the engine.
B. Check the current position of the DEF gauge.
C. Turn the keyswitch to OFF.
D. Clean dirt and debris from around the tank cap before removing the cap. Add or remove DEF from the DEF tank.
Note : Only use DEF that meets ISO 22241 quality standards.
E. Turn the keyswitch to ON. Do not start the engine.
F. Check for a change in the DEF gauge position.
DEF Gauge
Result : The gauge did not move by adding or removing DEF from the tank.
Proceed to Test Step 3.
Result : The gauge moved by adding or removing DEF from the tank.
Proceed to Test Step 4.
3. Check the Electrical Connection at the DEF Tank Header.
A. Turn the keyswitch to OFF.
B. Inspect the electrical connections to the DEF tank header. Refer to Troubleshooting, "Electrical Connectors - Inspect" for further information.
C. Inspect the connections for corrosion or loose wires.
Electrical Connections
Result : The electrical connections are free of corrosion and loose wires.
Repair : Replace the DEF tank header.
Proceed to Test Step 10.
Result : The electrical connections are not free of corrosion or loose wires.
Repair : Make the necessary repairs.
Proceed to Test Step 10.
4. Inspect the DEF lines for leaks.
A. Turn the keyswitch to ON. Do not start the engine.
B. Connect to the "Aftertreatment Diesel Exhaust Fluid Controller #1" using Cat ET.
C. Navigate to "Diagnostics Tests".
D. Perform the "DEF Dosing System