C4.4 Engines DEF Pressure Is High Caterpillar

DEF Pressure Is High

C4.4 Engines [UENR0662]

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C4.4 Engines DEF Pressure Is High

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Table 1
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 Diesel Exhaust Fluid Doser Absolute Pressure : 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 to identify the root cause of the fault.

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Table 2
Required Tools
Tool	Part Number	Part Description	Qty
A	473-2944	Exhaust Parts Kit	1

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Illustration 1	g03790973
Typical view of the Pump and Electronics Unit (PEU) (1) DEF Pump (2) DEF pressure line connector (3) DEF suction line connection

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Illustration 2	g03790991
Typical view of the DEF tank (4) DEF tank header unit (5) DEF suction line connection (6) DEF return Line connection

Complete the procedure in the order in which the steps are listed.

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Table 3
Troubleshooting Test Steps	Values	Results
1. Check that the latest available software is installed and there are no applicable Technical Information Bulletins or Special Instruction documentation released A. Ensure that the latest software is installed on the engine ECM. B. Ensure that the latest software is installed on the Dosing Control Unit (DCU) If necessary, refer to Troubleshooting, "ECM Software - Install" for the correct procedure. C. Ensure all Technical Information Bulletins and/or Special Instruction documented for the issue and/or product are reviewed and followed.	Software and Publications	Result: The latest software is not installed. Repair: Install the latest engine ECM software and then install the latest DCU software. If necessary, refer to Troubleshooting, "ECM Software - Install" for the correct procedure. Start the engine and wait for 2 minutes. If the fault is cleared, return the engine to service. If the fault is still present, proceed to Test Step 2. Result: Applicable Technical Information Bulletin/Special Instruction publication is available. Repair: Review and follow instructions provided in the available publication. Result: The latest software is installed. Proceed to Test Step 2.
2. Check the DEF Lines for Restrictions A. Turn the keyswitch to the OFF position for 15 minutes. Ensure the DEF system purge and the cool-down cycle has completed. Note: The keyswitch must be OFF until the "Wait to Disconnect" lamp switches off to allow the DEF pump to purge, reset the code, and reset the Diesel Exhaust Fluid Controller (DCU). B. Remove the DEF pressure line from the DEF pump connection (2) and the DEF injector. Install Tooling (A) on the DEF pump and injector connections. C. Remove the DEF return line from the DEF tank header connection (6) and the DEF injector. Install Tooling (A) on the DEF tank header and injector connections. D. Inspect the DEF pressure line and the DEF return line for restrictions and/or obstructions. If necessary, use low-pressure air. E. Inspect the DEF return pipe in the DEF tank header for restrictions and/or obstructions. Note: Possible obstructions are ice, DEF deposits, or debris.	DEF suction line restriction	Result: An obstruction was found in a DEF line. Repair: Flush line with deionized water or clean low-pressure air. If necessary, replace the line. Proceed to Test Step 6. Result: An obstruction was found in the DEF tank header return pipe. Repair: Remove the DEF tank header from the DEF tank. Refer to Disassembly and Assembly, Manifold (DEF Heater) - Remove and Install. Flush the return pipe with deionized water or clean low-pressure air. If necessary, replace the DEF tank header. Install the DEF tank header in the DEF tank. Refer to Disassembly and Assembly, Manifold (DEF Heater) - Remove and Install. Proceed to Test Step 6. Result: An obstruction was not found. Proceed to Test Step 3.
3. Check for a Restriction in the DEF Pump Note: If necessary, move the engine to an area where the ambient temperature is at least 10° C (50° F) to perform this step. Make sure that the DEF temperature is at least 10° C (50° F)before performing this step. The DEF system will not prime if the temperature is too low. A. Connect the DEF pressure line to DEF pump connection (2). Place the other end of the DEF pressure line into a suitable container to collect the DEF. B. Turn the keyswitch to the ON position. Run the engine and check that DEF is flowing from the DEF pressure line into the container. Note: Do not run the engine for more than 120 seconds. C. Turn the keyswitch to the OFF position. Remove the DEF pressure line from the container immediately to prevent the DEF being sucked back into the line when the DEF system purges.	DEF pump restriction	Result: DEF did not flow from the DEF pressure line into the container. Repair: Replace the DEF pump. Refer to the Disassembly and Assembly manual for the correct procedure. Proceed to Test Step 7. Result: DEF flowed from the pressure line into the container. Proceed to Test Step 4.
4. Check for a Restriction in the DEF Injector Note: If necessary, move the engine to an area where the ambient temperature is at least 10° C (50° F) to perform this step. The DEF system will not prime if the ambient temperature is too low. A. Connect the DEF pressure line and the DEF return line to the DEF injector. Place the other end of the DEF return line into a suitable container to collect the DEF. B. Turn the keyswitch to the ON position. Run the engine and check that DEF is flowing from the DEF pressure line into the container. Note: Do not run the engine for more than 120 seconds. C. Turn the keyswitch to the OFF position. Remove the DEF pressure line from the container immediately to prevent the DEF being sucked back into the line when the DEF system purges.	DEF injector restriction	Result: DEF did not flow from the DEF return line into the container. Repair: Install a replacement DEF injector. Refer to Disassembly and Assembly for the correct procedure. Proceed to Test Step 5. Result: DEF flowed from the return line into the container. Proceed to Test Step 6.
5. Perform a DEF Dosing System Accuracy Test A. Turn the keyswitch to the OFF position. B. Remove the DEF injector. Refer to Disassembly and Assembly, "DEF Injector and Mounting - Remove and Install". Note: Leave all lines connected to the DEF injector. C. Install the DEF injector into Tooling B and Tooling C. D. Turn the keyswitch to the ON position. E. Connect to the electronic service tool. F. Perform the "DEF Dosing System Accuracy Test". Refer to Testing and Adjusting, "Aftertreatment SCR System Dosing Test" for the correct procedure. Note: This test takes approximately 7 to 8 minutes and includes the following phases: · Priming of the DEF system. · The dosing test which will take 6 minutes. · Purging of the DEF system. If the test only runs for 1 minute, repeat the test a further 5 times.	105 mL (3.6 fl oz) to 130 mL (4.4 fl oz)	Result: The amount of DEF collected was less than 105 mL (3.6 fl oz) or greater than 130 mL (4.4 fl oz). Proceed to Test Step 6. Result: The amount of DEF collected is within 105 mL (3.6 fl oz) to 130 mL (4.4 fl oz). Proceed to Test Step 7.
6. Install a Replacement DEF Pump Filter A. Install a new DEF pump filter. Refer to the Operation and Maintenance Manual, "Diesel Exhaust Fluid Filter - Clean/Replace". B. Turn the keyswitch to the OFF position until the wait-to-disconnect lamp switches off. Note: The keyswitch must be OFF until the wait-to-disconnect lamp switches off to allow the DEF pump to purge, reset the code, and reset the DCU. C. Use the electronic service tool to check for active diagnostic codes.	Diagnostic codes	Result: The active diagnostic code has been eliminated. Proceed to Test Step 7. Result: The active diagnostic code is still present. Contact the Dealer Solutions Network (DSN).
7. Perform a "Aftertreatment System Functional Test" A. Start the engine. B. Connect to the electronic service tool. C. Perform the "Aftertreatment System Functional Test".	Functional test	Result: The test was successful. Return the unit to service. Result: The test was not successful. There are extra codes. Repair: Troubleshoot the additional codes. Refer to Troubleshooting, "Diagnostic Trouble Codes". Repeat Test Step 5. Result: The test was not successful. There are no additional codes. Contact the Dealer Solutions Network (DSN).