HEAD 1265060 - Caterpillar

Table 6
Troubleshooting Test Steps Values Results
6. Replace the Affected DEF Pump Filters
A. Clean the area around the affected pump filters.
B. Replace the DEF pump suction line filter fitting and DEF pump filter on the affected DEF pump.
DEF Pump Filters
Result: The affected DEF pump filters were replaced.
Proceed to Test Step 7.
7. Check the DEF Pump
A. Turn the keyswitch to ON. Do not start the engine.
B. Connect Cat ET.
C. Select the appropriate 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"
- For Aftertreatment #2 DEF System #1 perform the "Aftertreatment #2 DEF Dosing System #1 Prime Test"
- For Aftertreatment #2 DEF System #2 perform the "Aftertreatment #2 DEF Dosing System #2 Prime Test"
E. Use Cat ET to monitor the DEF Pressure during the test to see if the pressure stabilizes.
DEF Pump
Result: The DEF pump maintained at least 800 kPa (116 psi) during the test.
Proceed to Test Step 9.
Result: The DEF pump did not maintain at least 800 kPa (116 psi) during the test.
Proceed to Test Step 8.
Illustration 3 g06300725
(8) DEF backflow valve for Aftertreatment #1 DEF pump #1 system (blue)
(9) DEF backflow valve for Aftertreatment #1 DEF pump #2 system (green)
(10) DEF backflow valve for Aftertreatment #2 DEF pump #1 system (yellow)
(11) DEF backflow valve for Aftertreatment #2 DEF pump #2 system (red)
Table 7
Troubleshooting Test Steps Values Results
8. Check the Backflow Valve
A. Turn the keyswitch to OFF. Allow 2 minutes to elapse before proceeding.
B. Disconnect the electrical and DEF line connections from the affected backflow valve.
C. Remove the affected backflow valve from the pump electronics tank unit (PETU) assembly.
D. Pour water or blow low-pressure air through the large fitting on the backflow valve. Do NOT pour water or blow air through the small fitting as this may lift the valve off the seat and cause the backflow valve to appear to be failed.
Note: The backflow valve is normally closed and water/low-pressure air should not flow through the large fitting to the small fitting on the backflow valve assembly.
Backflow Valve
Result: The water/low-pressure air does not flow through the backflow valve.
Repair: Replace the DEF pump. Refer to the Disassembly and Assembly manual for additional information.
Proceed to Test Step 10.
Result: The water/low-pressure air flows through the backflow valve.
Repair: Replace the failed backflow valve. Refer to the Disassembly and Assembly manual for additional information.
Proceed to Test Step 10.
Illustration 4 g06300820
(12) DEF header
(13) Sock filter
(14) DEF header filter
Table 8
Troubleshooting Test Steps Values Results
9. Replace the Filters and Flush the DEF Tank
A. Turn the keyswitch to OFF.
B. Remove the DEF header from the DEF tank.
C. Flush the DEF tank. Refer to Testing and Adjusting, "Diesel Exhaust Fluid Tank - Flush" for additional information.
D. Replace the DEF header filter and DEF header sock filter on each of the DEF headers. Refer to Testing and Adjusting, "Diesel Exhaust Fluid Tank - Flush" for additional information.
DEF Tank Filters
Result: The DEF tank was