50212-ZV4-000 Honda BLOCK, FRICTION (Honda Code 2798080).

Table 1
J1939 Code and Description CDL Code and Description Comments
4334-15
Aftertreatment #1 DEF #1 Pressure (absolute) : High - least severe (1) 3090-20
Aftertreatment #1 DEF Pressure Sensor : Data Drifted High The Diesel Exhaust Fluid Control Unit (DCU) detects that the Diesel Exhaust Fluid (DEF) pump 1 pressure is above the acceptable range.
The code is logged.
4334-16
Aftertreatment #1 DEF #1 Pressure (absolute) : High - moderate severity (2) E930 (1)
High Aftertreatment #1 DEF Pressure The DCU detects that the DEF pump 1 pressure is above the acceptable range.
The code is logged.
7459-15
Aftertreatment #1 DEF Doser #2 Absolute Pressure : High - least severe (1) 5006-20
Aftertreatment #1 Diesel Exhaust Fluid Pressure #2 Sensor : Data Drifted High The DCU detects that the DEF pump 2 pressure is above the acceptable range.
The code is logged.
7459-16
Aftertreatment #1 DEF Doser #2 Absolute Pressure : High - moderate severity (2) E1705 (1)
High Aftertreatment #1 DEF Pressure #2 The DCU detects that the DEF pump 2 pressure is above the acceptable range.
The code is logged. Probable Causes
Codes
Backflow line
DEF pump
Backflow valveRecommended Actions
Illustration 1 g06074147
The DEF pumps are on the front side of the Pump Electronic Tank Unit (PETU).
(1) DEF pump 1
(2) Coolant diverter valve for pump 2 system
(3) DEF header for pump 1 system
(4) Backflow valve for pump 1 system
(5) Electrical connection for DEF header 2
(6) Coolant diverter valve for pump 1 system
(7) DEF pump 2
(8) Electrical connection for DEF header 1
(9) DEF header for pump 2 system
(10) Backflow valve for pump 2 system
Table 2
Troubleshooting Test Steps Values Results
1. Check the 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 any associated codes before continuing with this test.
Result: A code is active or logged.
Proceed to Test Step 2.
2. Check the Backflow Lines for a Restriction
A. Turn the keyswitch to the OFF position. Allow 2 minutes to elapse before proceeding.
B. Remove the appropriate backflow line between the backflow valve and the Diesel Exhaust Fluid (DEF) tank header.
C. Inspect the backflow lines for obstructions. Flush line with water/low pressure air if necessary.
Possible obstructions are ice, DEF deposits, or debris.
Restriction
Result: An obstruction was found in the backflow line.
Repair: Flush the line or replace the line.
Proceed to Test Step 5.
Result: An obstruction was not found in the backflow line.
Proceed to Test Step 3.
Illustration 2 g06026979
Table 3
3. Check for a Restriction in the DEF Pump
A. Reinstall the backflow line onto the DEF pump. Place the end of the line that would normally be installed onto the backflow valve into a beaker to collect the DEF.
B. Turn the keyswitch to the ON position. Do not start the engine.
C. Connect Cat ET.
D. Select the "Catalyst Reduction System".
E. Use Cat ET to 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 CANCEL to abort the test.
DEF
Result: DEF flowed from the backflow line into the container.
Reinstall the backflow line onto the backflow valve.
Proceed to Test Step 4.
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 additional information.
Proceed to Test Step 5.
4. Check for a Failed Backflow Valve
A. Reinstall the backflow line onto the backflow valve. Place the end of the line that would normally be installed onto the DEF header into a beaker to collect the DEF.
B. Turn the keyswitch to the ON position. Do not start the engine.
C. Connect Cat ET.
D. Select the "Catalyst Reduction System".
E. Use Cat ET to 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 CANCEL to abort the test.
DEF
Result: DEF flowed from the backflow line into the container.
Reinstall the backflow line onto the DEF header.
Proceed to Test Step 5.
Result: DEF did not flow from the DEF backflow line into the container.
Repair: Replace the backflow valve and reinstall all DEF lines. Refer to the Disassembly and Assembly manual for the additional information.
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. Use Cat ET to 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.
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).