DEF Pressure Is High
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| Diagnostic Trouble Codes for DEF Pressure Is High | |||
|---|---|---|---|
| J1939 Code | CDL Code | Code Description (code descriptions may vary) |
Comments |
| 4334-16 | E930 (2) | Aftertreatment #1 DEF #1 Pressure (absolute) : High - moderate severity (2) | The DCU detects that the DEF pump pressure is above the acceptable range. The code is logged. |
| Follow the troubleshooting procedure in order to identify the root cause of the fault. | |||
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 | |
| Illustration 1 | g03843796 |
(1) Backflow line connection at the DEF tank header (2) Backflow line connection at the DEF Pump (3) Connector for pressure line at the DEF pump | |
Complete the procedure in the order in which the steps are listed.
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| Troubleshooting Test Steps | Values | Results |
|---|---|---|
1. Check the DEF Lines for a Restriction A. Turn the keyswitch to the OFF position. Allow 2 minutes to elapse before proceeding. B. Remove the backflow line from DEF tank header (1) and DEF pump (2) . C. Remove the pressure line from the DEF pump (3) and the DEF injector. D. Inspect the removed lines for obstructions. Note: Possible obstructions are ice, DEF deposits, debris, or a trapped line. |
DEF return line restriction |
Result: An obstruction was found. Repair: If the line is blocked, flush line with water/low pressure air. If the line is trapped, reroute the line. If necessary, replace the line. Proceed to Test Step 4. Result: An obstruction was not found. Proceed to Test Step 2. |
2. Replace the Pressure and Backflow Fittings A. Replace the pressure and backflow fittings on the DEF pump. Refer to Disassembly and Assembly, "Diesel Exhaust Fluid Pump - Remove and Install" for the correct procedure. |
Replace Backflow Fitting |
Result: The fittings were replaced. Proceed to Test Step 3. |
3. Check for a Restriction in the DEF Pump A. Connect the pressure line to DEF pump (3) and the DEF injector. B. Connect the backflow line to DEF pump (2) . Place the other end of the line into a suitable container to collect the DEF. C. Turn the keyswitch to the ON position. Do not start the engine. D. Connect to the electronic service tool. E. Perform the "DEF Dosing System Verification Test". Refer to Systems Operation, Testing, and Adjusting, "Aftertreatment SCR System Dosing Test". Wait for the test to complete. |
DEF pump restriction |
Result: DEF did not flow from the DEF backflow line into the container. Repair: Replace the DEF pump. Refer to Disassembly and Assembly, "Diesel Exhaust Fluid Pump - Remove and Install" for the correct procedure. Proceed to Test Step 4. Result: DEF flowed from the backflow line into the container. Repair: Connect the backflow line to DEF tank header (1) . Proceed to Test Step 4. |
| 4. Perform a "Aftertreatment System Functional Test " A. Start the engine. B. Connect to the electronic service tool. C. Perform the "Aftertreatment System Functional Test ". |
Diagnostic code |
Result: The test was successful. Return the unit to service. Result: The test was not successful. There are additional codes. Repair: Troubleshoot the additional codes. Refer to Troubleshooting, "Diagnostic Trouble Codes". Repeat Test Step 4. Result: The test was not successful. There are no additional codes. Contact the Dealer Solutions Network (DSN). |
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