0395847 JOHNSON FUEL PUMP ASSY.

Table 1
J1939 Code and Description CDL Code and Description System Response
4335-15
Aftertreatment #1 SCR Dosing Air Assist Absolute Pressure : High - least severe (1) E1969 (1)
Aftertreatment #1 SCR Dosing Air Assist Absolute Pressure : High - least severe (1) The code is logged.
The air pressure is above the trip point for the programmed delay time.
Dosing is disabled until the pressure is correct. Note: Use Cat® Electronic Technician (Cat ET) Service Tool to verify any suspected code. Determine what codes are present. Evaluate all codes for possible interaction. Refer to Troubleshooting, "Event Codes" for information about event codes.
Table 2
Associated Codes
J1939 Code CDL Code Troubleshooting Procedure
4335-3 3092-3 Troubleshooting, "Sensor Signal (Analog, Active) - Test"
4335-4 3092-4 Troubleshooting, "Sensor Signal (Analog, Active) - Test"
4336-5 3094-5 Troubleshooting, "Solenoid Valve - Test"
4336-6 3094-6 Troubleshooting, "Solenoid Valve - Test"
Table 3
Troubleshooting Test Steps Values Results
1. Check for Diagnostic Trouble Codes.
A. Turn the breaker to the ON position.
B. Establish communication between Cat ET and the ECM. Refer to Troubleshooting, "Electronic Service Tools", if necessary.
C. Determine if a code is active or logged.
Codes
Result: An associated code is present.
Proceed to the appropriate troubleshooting procedure.
Result: A E1969 or 4335-15 code is present.
Proceed to Test Step 2.
2. Check the Air Supply to the Dosing Cabinet.
A. Turn the breaker to the OFF position.
B. Disconnect the air supply line to the dosing cabinet.
C. Install a pressure gauge on the air supply line to the dosing cabinet.
Air Supply
Results: The air supply pressure from the air compressor is between 724 kPa (105 psi) and 1068 kPa (155 psi).
Connect all air lines to the dosing cabinet.
Proceed to Test Step 4.
Results: The air supply pressure form the air compressor is greater than 1068 kPa (155 psi).
Repair: There is a problem with the air supply to the dosing cabinet. Refer to the air compressor manufacturer or air supply source for the appropriate troubleshooting material.
Verify that the repair resolved the issue.
3. Check the Air Pressure.
A. Turn the breaker to the ON position.
B. Use Cat ET to activate the following overrides:
- Aftertreatment #1 SCR Dosing Air Assist Valve Command Override
C. Monitor the "SCR Dosing Air Assist Absolute Pressure" in the Cat ET the override screen.
Air Pressure
Results: The air pressure at the "SCR Dosing Air Assist Absolute Pressure" is equal to 515 kPa (74.7 psi) - 570 kPa (82.7 psi).
The system is working properly. Return to service.
Results: The air pressure at the "Aftertreatment #1 Supply Air Pressure" is greater than 469 kPa (68 psi).
Proceed to Test Step 4.
4. Check the Dosing Cabinet Outlet Air Pressure.
A. Turn the breaker to the ON position.
B. Disconnect the DEF injector air line from the dosing cabinet.
C. Install a pressure gauge on the outlet of the dosing cabinet air manifold.
D. Turn the breaker to the ON position.
E. Use Cat ET to activate the following overrides:
- Aftertreatment #1 SCR Dosing Air Assist Valve Command Override
F. Monitor the pressure gauge and record the reading.
Air Pressure
Results: The air pressure at the outlet of the dosing cabinet air manifold is equal to 414 kPa (60 psi) - 469 kPa (68 psi).
Repair: Replace the Aftertreatment #1 Air Pressure Sensor.
Verify the repair resolved the issue. Return to service.
Results: The air pressure at the outlet of the dosing cabinet air manifold is greater than 469 kPa (68 psi).
Repair: Replace the air pressure regulator on the air manifold.
Verify the repair resolved the issue. Return to service.