0322784 JOHNSON SCREW,Silencer to carb.

Table 1
J1939 Code and Description CDL Code and Description Comments
4337-8
Aftertreatment #1 DEF Doser #1 Temperature : Abnormal Frequency, Pulse Width, or Period 3096-8
Aftertreatment #1 DEF Temperature #1 Sensor : Abnormal Frequency, Pulse Width, or Period The Diesel Exhaust Fluid Controller (DCU) detects an abnormal temperature signal from the pump.
The code is logged.
4374-8
Aftertreatment #1 DEF Pump #1 Motor Speed : Abnormal Frequency, Pulse Width, or Period 3118-8
Aftertreatment #1 DEF Pump Motor Speed Sensor : Abnormal Frequency, Pulse Width, or Period The DCU detects an abnormal motor speed signal from the pump.
The code is logged.
4376-7
Aftertreatment #1 DEF Return Valve : Not Responding Properly 3862-7
Aftertreatment #1 DEF Return Valve Solenoid : Not Responding Properly The DCU detects that the return valve is not responding properly.
The code is logged. Probable Causes
Codes
DEF pump connector or harness
DEF pumpRecommended Actions
Table 2
Troubleshooting Test Steps Values Results
1. Check for Codes
A. Connect to Cat® Electronic Technician (ET) and check for active or logged codes.
Codes
Result: There are no active or logged codes present.
Proceed to Test Step 2.
Result: There is an active or logged code found.
Repair: Troubleshoot any code found before continuing with this procedure. Refer to Troubleshooting , Diagnostic Trouble Codes or Event Codes for the appropriate procedure.
2. Inspect the Harness Connector at the DEF Pump
A. Turn the keyswitch to OFF for 2 minutes.
Note: The keyswitch must be OFF for 2 minutes to allow the DEF pump to purge, reset the code, and reset the DCU.
B. Disconnect the DEF pump electrical connector.
C. Inspect the connector terminals for DEF contamination or corrosion.
DEF pump connector
Result: The DEF pump connector was free of DEF contamination or corrosion.
Proceed to Test Step 3.
Result: The DEF pump connector was not free of DEF contamination or corrosion.
Repair: Replace the PETU wiring harness.
Proceed to Test Step 3.
3. Replace the DEF Pump
A. Turn the keyswitch to OFF for 2 minutes.
Note: The keyswitch must be OFF for 2 minutes to allow the DEF pump to purge, reset the code, and reset the DCU.
B. Replace the DEF pump. Refer to the Disassembly and Assembly manual for the correct procedure.
C. Establish communication between Cat ET and the Diesel Exhaust Fluid Controller #1 ECM.
D. Perform the "DEF Dosing System Verification Test" to pressurize and prime the system.
E. Visually inspect all DEF lines from the tank to the DEF injector for leakage.
Leakage
Result: The lines are not leaking.
Proceed to Test Step 4.
Result: The lines are leaking.
Repair: Make the necessary repairs and repeat the "DEF Dosing System Verification Test".
Proceed to Test Step 4.
4. Perform an "Aftertreatment System Functional Test"
A. Turn the keyswitch to ON.
B. Establish communication between Cat ET and the "Engine #1 Aftertreatment Controller".
C. Perform an "Aftertreatment System Functional Test".
Aftertreatment System Functional Test
Result: The "Aftertreatment System Functional Test" was successful and the code cleared.
Return the unit to service.
Result: The "Aftertreatment System Functional Test" was not successful and additional codes were logged.
Repair: Troubleshoot the additional codes, Refer to Troubleshooting for the correct procedure.
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).