2279 Mercruiser PISTON AND PISTON PIN ASSEMBLY (.030 O.S.)

Table 1
J1939 Code and Description CDL Code and Description Comments
4334-3
Aftertreatment #1 DEF #1 Pressure (absolute) : Voltage Above Normal 3090-3
Aftertreatment #1 DEF Pressure #1 Sensor : Voltage Above Normal There is excessive voltage on the signal wire between the Diesel Exhaust Fluid Control Unit (DCU) and the DEF pump, or there is an open circuit on the supply, signal, or return wire for DCU/DEF pump #1. The code is logged.
The code is logged.
4334-4
Aftertreatment #1 DEF #1 Pressure (absolute) : Voltage Below Normal 3090-4
Aftertreatment #1 DEF Pressure #1 Sensor : Voltage Below Normal There is low voltage on the signal wire between the DCU #1 and the DEF #1 pump pressure sensor.
The code is logged.
4387-3
Aftertreatment #2 DEF #1 Pressure (absolute) : Voltage Above Normal 3091-3
Aftertreatment #2 DEF Pressure #1 Sensor : Voltage Above Normal There is excessive voltage on the signal wire between the Aftertreatment #1 DCU #2 and Aftertreatment #1 DEF pump #2, or there is an open circuit on the supply, signal, or return wire for the Aftertreatment #1 DCU/DEF pump #2.
The code is logged.
4387-4
Aftertreatment #2 DEF #1 Pressure (absolute) : Voltage Below Normal 3091-4
Aftertreatment #2 DEF Pressure #1 Sensor : Voltage Below Normal There is low voltage on the signal wire between Aftertreatment #1 DCU #2 and the Aftertreatment #1 DEF pump #2 pressure sensor.
The code is logged.
7459-3
Aftertreatment #1 DEF Doser #2 Absolute Pressure : Voltage Above Normal 5006-3
Aftertreatment #1 DEF Pressure #2 Sensor : Voltage Above Normal There is excessive voltage on the signal wire between the DCU and the DEF pump, or there is an open circuit on the supply, signal, or return wire for DCU/DEF pump #2.
The code is logged.
7459-4
Aftertreatment #1 DEF Doser #2 Absolute Pressure : Voltage Below Normal 5006-4
Aftertreatment #1 DEF Pressure #2 Sensor : Voltage Below Normal There is low voltage on the signal wire between the DCU #2 and the DEF #2 pump pressure sensor.
The code is logged.
7464-3
Aftertreatment #2 DEF Doser #2 Pressure (absolute) : Voltage Above Normal 5007-3
Aftertreatment #2 DEF Pressure #2 Sensor : Voltage Above Normal There is excessive voltage on the signal wire between the Aftertreatment #2 DCU #2 and Aftertreatment #2 DEF pump #2, or there is an open circuit on the supply, signal, or return wire for the Aftertreatment #2 DCU/DEF pump #2.
The code is logged.
7464-4
Aftertreatment #2 DEF Doser #2 Pressure (absolute) : Voltage Below Normal 5007-4
Aftertreatment #2 DEF Pressure #2 Sensor : Voltage Below Normal There is low voltage on the signal wire between Aftertreatment #2 DCU #2 and the Aftertreatment #2 DEF pump #2 pressure sensor.
The code is logged.
Table 2
Required Tools
Part Number Part Name Qty
372-5260 Test Kit 1
Illustration 1 g06201026
Illustration 2 g06522418
(1) Aftertreatment #1 DCU #1 (blue)
(2) Aftertreatment #1 DCU #2 (green)
(3) Aftertreatment #2 .DCU #1 (yellow)
(4) Aftertreatment #2 .DCU #2 (red)
(5) Aftertreatment #1 DEF pump #1 (blue)
(6) Aftertreatment #1 DEF pump #2 (green)
(7) Aftertreatment #2 DEF pump #1 (yellow)
(8) Aftertreatment #2 DEF pump #2 (red)
Table 3
Troubleshooting Test Steps Values Results
1. Check for Codes
A. Connect Cat® Electronic Technician (ET) to the service tool connector.
B. Determine if a code is active or logged.
Codes
Result: A code is active or logged.
Proceed to Test Step 2.
2. Check the Pump Electronic Tank Unit (PETU) Wiring Harness for the DEF Pump Pressure Sensor an Open Circuit
A. Turn the keyswitch to OFF for 2 minutes. The keyswitch must be OFF for 2 minutes to allow the DEF pump to purge, reset the code, and reset the Diesel Exhaust Fluid Control Unit (DCU).
B. Disconnect the PETU wiring harness from the appropriate DEF pump and the appropriate DCU.
C. Connect the 398-5063 Probe to the affected DCU wiring harness connector.
D. Connect the 398-5056 Probe to the affected DEF pump wiring harness connector.
The probe must be used to prevent damage to the DCU and DEF pump wiring harness connector.
E. Measure the resistance between the following terminals:
- Terminal 2 (SUPPLY) on the affected DEF pump wiring harness connector and Terminal 19 (SUPPLY) on the 86 pin affected DCU wiring harness connector.
- Terminal 3 (SIGNAL) on the affected DEF pump wiring harness connector and Terminal 17 (SIGNAL) on the 86 pin affected DCU wiring harness connector.
- Terminal 4 (GROUND) on the affected DEF pump wiring harness connector and Terminal 18 (GROUND) on the 86 pin affected DCU wiring harness connector.
Open Circuit
Result: There were less than 10 Ohms of resistance on all the DEF pump pressure circuit wires.
Proceed to Test Step 3.
Result: There were more than 10 Ohms of resistance on any one of the DEF pump pressure circuit wires.
Repair: There is an open in the wiring harness. Repair or replace the wiring harness.
If the problem is not resolved, proceed to Test Step 5.
3. Check the PETU Wiring Harness for the DEF Pump Pressure Sensor a Short Circuit
A. Turn the keyswitch to "OFF".
B. Disconnect the PETU wiring harness from the affected DEF pump and the