0398867 JOHNSON FUEL PUMP ASSY.

Table 1
J1939 Code and Description Comments
4335-15
Aftertreatment #1 SCR Dosing Air Assist Absolute Pressure : High - least severe (1) The air pressure is above the trip point for the programmed delay time.
Dosing is disabled until the pressure is correct.
The code is logged.
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" Probable Causes
Codes
Air pressureRecommended Actions
Table 3
Troubleshooting Test Steps Values Results
1. Check for Codes
A. Turn the DC breaker, located in the power distribution box, to the ON position.
B. Connect Cat® Electronic Technician (ET) 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.
Proceed to Test Step 2.
2. Check the Air Supply to the Dosing Cabinet
A. Turn the DC breaker, located in the power distribution box, 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.
D. Monitor the air supply pressure from the air compressor.
E. Reconnect the air supply line to the dosing cabinet.
483 kPa to 1068 kPa (70 psi to 155 psi)
Result: The air supply pressure from the air compressor is 483 kPa to 1068 kPa (70 psi to 155 psi).
Proceed to Test Step 4.
Result: The air supply pressure from the air compressor is greater than 1068 kPa (155 psi).
Repair: There is a problem with the air supply to the dosing cabinet. For information on the air compressor, refer to the Original Equipment Manufacturers (OEM) service information.
If the problem is not resolved, proceed to Test Step 3.
3. Check the Air Pressure
A. Turn the DC breaker, located in the power distribution box, to the ON position.
B. Connect Cat ET.
C. Use Cat ET to perform the following override:
- Set the "Aftertreatment #1 SCR Dosing Air Assist Valve Command Override" to the ON position.
D. Use Cat ET to monitor the following pressure:
- "Aftertreatment #1 Supply Air Pressure"
414 kPa to 469 kPa (60 psi to 68 psi)
Result: The air pressure at the "Aftertreatment #1 Supply Air Pressure" sensor is 414 kPa to 469 kPa (60 psi to 68 psi).
The system is working properly. Return to service.
Result: The air pressure at the "Aftertreatment #1 Supply Air Pressure" sensor is greater than 469 kPa (68 psi).
Proceed to Test Step 4.
4. Check the Dosing Cabinet Outlet Air Pressure
A. Turn the DC breaker, located in the power distribution box, to the OFF 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 DC breaker, located in the power distribution box, to the ON position.
E. Connect Cat ET.
F. Use Cat ET to perform the following override:
- Set the "Aftertreatment #1 SCR Dosing Air Assist Valve Command Override" to the ON position.
G. Monitor the pressure gauge and record the reading.
414 kPa to 469 kPa (60 psi to 68 psi)
Result: The air pressure at the outlet of the dosing cabinet air manifold is 414 kPa to 469 kPa (60 psi to 68 psi).
Repair: Replace the "Aftertreatment #1 Supply Air Pressure" sensor.
Verify that the repair eliminated the problem.
Result: The air pressure at the outlet of the dosing cabinet air manifold is greater than 469 kPa (68 psi).
Repair: Refer to Testing and Adjusting , Air Pressure Regulator - Test and Adjust to adjust the air pressure to the proper specification.
Verify that the repair eliminated the problem.
If the adjustment did not fix the problem, replace the regulator.
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).