0394716 JOHNSON FUEL PUMP ASSY., Lower

Table 1
J1939 Code and Description CDL Code and Description Comments
4334-7
Aftertreatment #1 DEF #1 Pressure (absolute) : Not Responding Properly 3090-7
Aftertreatment #1 DEF Pressure Sensor : Not Responding Properly The Aftertreatment #1 Diesel Exhaust Fluid Control Unit (DCU) #1 detects signal voltage that is not in the acceptable range.
The code is logged.
7459-7
Aftertreatment #1 DEF Doser #2 Absolute Pressure : Not Responding Properly 5006-7
Aftertreatment #1 Diesel Exhaust Fluid Pressure #2 Sensor : Not Responding The Aftertreatment #1 DCU #2 detects signal voltage that is not in the acceptable range.
The code is logged.
Table 2
Required Tools
Part Number Part Name Qty
441-0451 Tool Gp 1 Probable Causes
Codes
DEF lines
Pump filters
Header filters
DEF injector
Backflow valveRecommended Actions
Table 3
Troubleshooting Test Steps Values Results
1. Check for Codes
A. Connect Cat® Electronic Technician (ET) to the service tool connector.
B. Look for active codes that are associated with the system for the event code.
Codes
Result: An associated code is active.
Repair: Troubleshoot the associated code before continuing with this test.
Result: A code is active or logged.
Proceed to Test Step 2.
Illustration 1 g06022979
The DEF pumps are on the front side of the Pump Electronic Tank Unit (PETU).
(1) DEF pump 1
(2) DEF pump 2
Illustration 2 g06023592
The DEF injectors are on the inlet of the Clean Emissions Module (CEM).
(3) DEF injector 2 (DEF pump 1)
(4) DEF injector 3 (DEF pump 1)
(5) DEF injector 1 (DEF pump 2)
(6) DEF injector 4 (DEF pump 2)
Table 4
Troubleshooting Test Steps Values Results
2. Inspect all the DEF Lines for Leaks
A. Turn the keyswitch to the ON position. Do not start the engine.
B. Connect Cat ET.
C. Select the appropriate "Diesel Exhaust Fluid Control Unit (DCU)".
D. Perform the following diagnostic test to pressurize the system:
- For DEF System #1 perform the "Aftertreatment #1 DEF Dosing System #1 Prime Test"
- For DEF System #2 perform the "Aftertreatment #1 DEF Dosing System #2 Prime Test"
Refer to Troubleshooting, Cat ET Service Features for additional information.
E. Visually inspect all DEF lines from the tank to the DEF injectors. Look for pinched, damaged, or disconnected lines.
F. Turn the keyswitch to the OFF position.
DEF Lines
Result: The lines are not leaking, damaged, pinched, or disconnected.
Proceed to Test Step 3.
Repair: The lines are leaking, damaged, pinched, or disconnected.
Result: Repair or replace the damaged components.
If the problem is not resolved, proceed to Test Step 3.
3. Verify that the DEF Lines Installed Correctly
A. Check each of the following locations:
- DEF pump
- DEF header
- Backflow valve
- DEF injectors
B. Check for excessive bending, pinching, or restrictions in the DEF lines.
Connections
Result: The DEF lines are routed to the correct locations.
Proceed to Test Step 2.
Repair: The DEF lines are not to the correct locations.
Result: Route the DEF lines to the correct locations.
Proceed to Test Step 10.
Illustration 3 g06029326
(7) DEF suction line filter fitting
(8) DEF pump
(9) DEF pump filter cap
Table 5
Troubleshooting Test Steps Values Results
4. Replace the DEF Pump Filters
A. Turn the keyswitch to the OFF position. Allow 2 minutes to elapse before proceeding.
B. Clean the area around the DEF pump filters.
C. Disconnect the suction line from the appropriate DEF pump.
D. Replace the DEF pump suction line filter fitting and DEF pump filter on the appropriate DEF pump. Refer to the Disassembly and Assembly manual for the additional information.
DEF Pump Filters
Result: The DEF pump filters were replaced.
Proceed to Test Step 5.
5. Perform an "Aftertreatment Dosing System Functional Test"
A. Turn the keyswitch to the ON position. Do not start the engine.
B. Connect Cat ET.
C. Select the "Selective Catalyst Reduction System".
D. Perform the following diagnostic test:
-"Aftertreatment Dosing System Functional Test"
Refer to Troubleshooting, Cat ET Service Features for additional information.
Note: When the test prompts to proceed to clear active diagnostics, select ACCEPT.
Test
Result: The test was successful.
Return to service.
Result: The test was not successful.
Proceed to Test Step 6.
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