0327745 JOHNSON ORIFICE, No. 40

Table 1
J1939 Code and Description CDL Code and Description Comments
6875-16
Aftertreatment #1 DEF Dosing Pressure : High - moderate severity (2) E930 (2)
High Aftertreatment #1 DEF Pressure The Diesel Exhaust Fluid (DEF) pressure is above the threshold for proper system operation.
DEF dosing is disabled.
Table 2
Associated Codes
J1939 Code CDL Code Troubleshooting Procedure
4335-15 E1969 (1) Troubleshooting, "Air Assist Pressure Is High"
4335-17 E964 (1) Troubleshooting, "Air Assist Pressure Is Low"
4335-18 E964 (2) Troubleshooting, "Air Assist Pressure Is Low"
4335-3 3092-3 Troubleshooting, "Sensor Signal (Analog, Active) - Test"
4335-4 3094-4 Troubleshooting, "Sensor Signal (Analog, Active) - Test"
4376-5 3862-5 Troubleshooting, "Solenoid Valve - Test"
4376-6 3862-6 Troubleshooting, "Solenoid Valve - Test"
6875-3 3090-3 Troubleshooting, "Sensor Signal (Analog, Active) - Test"
6875-4 3090-4 Troubleshooting, "Sensor Signal (Analog, Active) - Test"
Illustration 1 g03747254
Enhanced Troubleshooting Information (ETI) code
Probable Causes
Codes
Sensor
DEF line
DEF injector
DEF pump
Illustration 2 g06305577
DEF Component Locations
(1) DEF Injector Nozzle
(2) DEF Inlet Line Connection
(3) DEF Pump
(4) DEF Pressure SensorRecommended Actions
Table 3
Troubleshooting Test Steps Values Results
1. Check for Codes
A. Turn the DC breaker to ON.
B. Connect Cat® Electronic Technician (Cat ET) Service Tool to the service tool connector.
C. Look for active codes that are associated with the system for the event code.
Codes
Result: An associated code is active.
Repair: Troubleshoot any associated codes before continuing with this test.
Result: A code is active or logged.
Record the Enhanced Troubleshooting Information (ETI) code with the event.
Proceed to Test Step 2.
2. Monitor the Catalyst Intake Gas Temperature
A. Turn the DC breaker to ON.
B. Connect Cat ET.
C. Use Cat ET to monitor the following temperature:
- "Aftertreatment #1 SCR Catalyst Intake Gas Temperature"
Temperature
Result: The "Aftertreatment #1 SCR Catalyst Intake Gas Temperature" is less than 180° C (356° F)
Proceed to Test Step 3.
Result: The "Aftertreatment #1 SCR Catalyst Intake Gas Temperature" is 180° C (356° F) or higher.
Repair: Use Cat ET to perform the following override:
- Set the "Aftertreatment #1 SCR Dosing Air Assist Valve Command Override" to the OFF position.
Proceed to Test Step 3.
3. Check the DEF Pressure Sensor
A. Turn the DC breaker to ON.
B. Connect Cat ET.
C. Use Cat ET to monitor the following pressure:
- "Aftertreatment #1 DEF Dosing Pressure"
Sensor
Result: The DEF pressure sensor reads 0 20 kPa (0 3 psi).
Proceed to Test Step 4.
Result: The DEF pressure sensor does not read 0 20 kPa (0 3 psi).
Repair: Replace the DEF pressure sensor.
Proceed to Test Step 10.
4. Determine the ETI Code
A. Use the ETI code recorded in Step 1 to determine the troubleshooting.
Code
Result: An ETI code of 4 is present.
Proceed to Test Step 7.
Result: An ETI code of 1 is present. A failed DEF injector has been detected.
Repair: Clean or replace the DEF injector. Refer to Specifications , Nozzle (DEF) for the proper torque procedure for the DEF injector nozzle.
Proceed to Test Step 10.
Result: An ETI code of 2 is present.
Proceed to Test Step 5.
Result: An ETI code of 3 is present.
Proceed to Test Step 6.
5. Check the Dosing Cabinet DEF Tank Suction Line Strainer for Blockage
A. Remove the DEF tank header assembly from the DEF tank.
B. Inspect the suction line strainer for a blockage or debris.
Blockage/Debris
Result: The suction line strainer was not blocked. A failed DEF return valve has been detected.
Repair: Replace the DEF return valve.
Result: The suction line strainer was blocked.
Repair: Clean the suction line strainer.
Proceed to Test Step 10.
6. Inspect the Pump Check Valves for Blockage or Failure
A. Remove the electrical power from the engine and aftertreatment.
B. Remove the manifold from the DEF pump. Refer to Disassembly and Assembly , Control Cabinet - Disassemble for additional information.
C. Inspect the two check valves for blockage or failure.
Blockage/Failure
Result: Blockage or a failed check valve was found.
Repair: Clean or replace the check valves.
Result: No blockage or failure was observed. A failed DEF pump has been detected.
Repair: Replace the DEF pump.
Proceed to Test Step 10.
7. Inspect the DEF Pressure Line
A. Turn the DC breaker to OFF.
B. Disconnect the DEF pressure line from the dosing cabinet.
C. Disconnect the DEF pressure line from the DEF injector.
D. Pour warm water through the DEF pressure line and verify that the line is not blocked.
DEF Line
Result: The DEF pressure line is not blocked.
Proceed to Test Step 8.
Result: The DEF pressure line is blocked.
Repair: Replace the DEF pressure line.
Proceed to Test Step 10.
8. Inspect the DEF Injector for Plugging
A. Turn the DC breaker to OFF.
B. Disconnect the DEF supply line at the DEF injector.
C. Remove the DEF injector from the exhaust.
D. Inspect the DEF injector for signs of plugging.
DEF Injector
Result: The DEF injector is not plugged.
Proceed to Test Step 9.
Result: The DEF injector is plugged.
Repair: Clean or replace the DEF injector. Refer to Specifications , Nozzle (DEF) for the torquing procedure.
Proceed to Test Step 10.