15631-ZW1-000ZA Honda EXTENSION, OIL FILLER *NH8* (Honda Code 4897666). (DARK GRAY)

Table 1
J1939 Code and Description CDL Code and Description Comments
7598-5
Aftertreatment #1 DEF Backflow Valve #1 : Current Below Normal 5024-5
Aftertreatment #1 Diesel Exhaust Fluid Backflow Valve #1 : Current Below Normal This code indicates that there is a problem with the aftertreatment #1 DEF backflow valve #1 and/or the electrical circuit for the backflow valve.
7598-6
Aftertreatment #1 DEF Backflow Valve #1 : Current Above Normal 5024-6
Aftertreatment #1 Diesel Exhaust Fluid Backflow Valve #1 : Current Above Normal This code indicates that there is a problem with the aftertreatment #1 DEF backflow valve #1 and/or the electrical circuit for the backflow valve.
7599-5
Aftertreatment #1 DEF Backflow Valve #2 : Current Below Normal 5025-5
Aftertreatment #1 Diesel Exhaust Fluid Backflow Valve #2 : Current Below Normal This code indicates that there is a problem with the aftertreatment #1 DEF backflow valve #2 and/or the electrical circuit for the backflow valve.
7599-6
Aftertreatment #1 DEF Backflow Valve #2 : Current Above Normal 5025-6
Aftertreatment #1 Diesel Exhaust Fluid Backflow Valve #2 : Current Above Normal This code indicates that there is a problem with the aftertreatment #1 DEF backflow valve #2 and/or the electrical circuit for the backflow valve.
Table 2
Required Tools
Part Number Part Name Qty
372-5260 Test Lead Tool Group 1
Illustration 1 g06072314
Illustration 2 g06063896
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) Electrical connection for DEF header 2
(5) Coolant diverter valve for pump 1 system
(6) Backflow valve for pump 1 system
(7) DEF pump 2
(8) Electrical connection for DEF header 1
(9) Backflow valve for pump 2 system
(10) DEF header for pump 2 system
Illustration 3 g06063900
The DEF injectors are on the inlet of the Clean Emissions Module (CEM).
(11) DEF injector 2 (DEF pump 1)
(12) DEF injector 3 (DEF pump 1)
(13) DEF injector 1 (DEF pump 2)
(14) DEF injector 4 (DEF pump 2)
Table 3
Troubleshooting Test Steps Values Results
1. Check for Codes
A. Connect Cat® Electronic Technician (ET) to the service tool connector.
B. Determine if a code is active or logged.
Codes
Result: A -5 code is active or logged.
Proceed to Test Step 2.
Result: A -6 code is active or logged.
Proceed to Test Step 3.
2. Check the Backflow Valve Wiring Harness for an Open Circuit
A. Turn the keyswitch to the OFF position. The keyswitch must be OFF for 2 minutes to allow the DEF pump to purge, reset the code, and reset the Diesel Exhaust Fluid Controllers (DCU’s).
B. Disconnect the Pump Electronic Tank Unit (PETU) wiring harness from the affected DEF backflow valve and the affected DCU.
C. Connect the 398-5063 Probe to the DCU connector.
The probe must be used to prevent damage to the DCU connector.
D. Measure the resistance between the following terminals on the affected DEF backflow valve wiring harness connector and the affected 86-pin DCU wiring harness connector:
- For Aftertreatment #1 DCU #1, Terminal 1 (Supply) on the affected DEF backflow valve wiring harness connector and Terminal 11 (DEF Backflow Valve (+)) on the 86-pin DCU connector.
- For Aftertreatment #1 DCU #1, Terminal 2 (Return) on the affected DEF backflow valve wiring harness connector and Terminal 31 (DEF Backflow Valve (-)) on the 86-pin DCU connector.
- For Aftertreatment #1 DCU #2, Terminal 1 (Supply) on the affected DEF backflow valve wiring harness connector and Terminal 11 (DEF Backflow Valve (+)) on the 86-pin DCU connector.
- For Aftertreatment #1 DCU #2, Terminal 2 (Return) on the affected DEF backflow valve wiring harness connector and Terminal 31 (DEF Backflow Valve (-)) on the 86-pin DCU connector.
Open Circuit
Result: There were less than 10 Ohms of resistance on all the circuit wires between the affected backflow valve and the affected DCU.
Proceed to Test Step 3.
Result: There were more than 10 Ohms of resistance on all the circuit wires between the affected backflow valve and the affected DCU.
Repair: An open circuit has been detected. Repair or replace the wiring harness.
Verify that the repair eliminated the problem.
Proceed to Test Step 5.
3. Check the Backflow Valve Wiring Harness for a Short Circuit
A. Turn the keyswitch to the OFF position. The keyswitch must be OFF for 2 minutes to allow the DEF pump to purge, reset the code, and reset the DCU’s.
B. Disconnect the PETU wiring harness from the affected DEF backflow valve and the affected DCU.
C. Connect the 398-5063 Probe to the DCU connector.
The probe must be used to prevent damage to the DCU connector.
D. Measure the resistance between the following terminals on the affected DEF backflow valve wiring harness connector and a known good chassis ground:
- For Aftertreatment #1 DCU #1, Terminal 1 (Supply) on the affected DEF backflow valve wiring harness connector and a known good ground.
- For Aftertreatment #1 DCU #1, Terminal 2 (Return) on the affected DEF backflow valve wiring harness connector and a known good ground.
- For Aftertreatment #1 DCU #2, Terminal 1 (Supply) on the affected DEF backflow valve wiring harness connector and a known good ground.
- For Aftertreatment #1 DCU #2, Terminal 2 (Return) on the affected DEF backflow valve wiring harness connector and a known good ground.
Short Circuit
Result: There were more than 100K Ohms of resistance on all the circuit wires between the affected backflow valve and a known good ground.
Proceed to Test Step 4.
Result: There were less than 100K Ohms of resistance on all the circuit wires between the affected backflow valve and a known good ground.
Repair: A short circuit has been detected. Repair or replace the wiring harness.
Verify that the repair eliminated the problem.
Proceed to Test Step 5.
4. Check the DCU Wiring Harness Connector for a Short Circuit
A. Turn the keyswitch to the OFF position. The keyswitch must be OFF for 2 minutes to allow the DEF pump to purge, reset the code, and reset the DCU’s.
B. Disconnect the PETU wiring harness from the affected DEF backflow valve and the affected DCU.
C. Connect the 398-5096 Probe to the DCU connector.
The probes must be used to prevent damage to the DCU connector.