78109 Mercruiser HOSE, THERMOSTAT HOUSING TO HEAT EXCHANGER(INBOARD)

Table 1
J1939 Code and Description CDL Code and Description Comments
3361-5
Aftertreatment #1 DEF Dosing Unit : Current Below Normal 3102-5
Aftertreatment #1 DEF Dosing Pump : Current Below Normal This code indicates that there is problem with the Diesel Exhaust Fluid (DEF) pump or the wiring harness.
3361-6
Aftertreatment #1 DEF Dosing Unit : Current Above Normal 3102-6
Aftertreatment #1 DEF Dosing Pump : Current Above Normal This code indicates that there is problem with the DEF pump or the wiring harness.
4451–5
Aftertreatment #2 DEF Dosing Unit : Current Below Normal 3109–5
Aftertreatment #2 DEF Dosing Unit : Current Below Normal This code indicates that there is problem with the DEF pump or the wiring harness.
4451–6
Aftertreatment #2 DEF Dosing Unit : Current Above Normal 3109–6
Aftertreatment #2 DEF Dosing Unit : Current Above Normal This code indicates that there is problem with the DEF pump or the wiring harness.
7457-5
Aftertreatment #1 DEF Dosing Unit #2 : Current Below Normal 5032–5
Aftertreatment #1 Diesel Exhaust Fluid Pump #2 : Current Below Normal This code indicates that there is problem with the DEF pump or the wiring harness.
7457-6
Aftertreatment #1 DEF Dosing Unit #2 : Current Above Normal 5032–6
Aftertreatment #1 Diesel Exhaust Fluid Pump #2 : Current Above Normal This code indicates that there is problem with the DEF pump or the wiring harness.
7462–5
Aftertreatment #2 Diesel Exhaust Fluid Dosing Unit #2 : Current Below Normal 5033–5
Aftertreatment #2 Diesel Exhaust Fluid Dosing Unit #2 : Current Below Normal This code indicates that there is problem with the DEF pump or the wiring harness.
7462–6
Aftertreatment #2 Diesel Exhaust Fluid Dosing Unit #2 : Current Above Normal 5033–6
Aftertreatment #2 Diesel Exhaust Fluid Dosing Unit #2 : Current Above Normal This code indicates that there is problem with the DEF pump or the wiring harness.
Table 2
Required Tools Qty
372-5260 Test Kit 1
Illustration 1 g06201026
Illustration 2 g06100059
(1) Aftertreatment #1 Diesel Exhaust Fluid (DEF) Pump #1
(2) Aftertreatment #1 DEF Pump #2
(3) Aftertreatment #2 DEF Pump #1
(4) Aftertreatment #2 DEF Pump #2
(5) Aftertreatment #1 Dosing Control Unit (DCU) #1
(6) Aftertreatment #1 DCU #2
(7) Aftertreatment #2 DCU #1
(8) Aftertreatment #2 DCU #2
Table 3
Troubleshooting Test Steps Values Results
1. Check the Pump Electronic Tank Unit (PETU) Wiring Harness for the DEF Pump Motor for an Open Circuit
A. Turn the keyswitch to "OFF". The keyswitch must be OFF for 2 minutes to allow the DEF pumps to purge, reset the code, and reset the DCU.
B. Disconnect the PETU wiring harness from the affected DEF pump and the affected Diesel Exhaust Fluid Control Unit (DCU).
C. Connect the 398-5063 Probe to the DCU wiring harness connector.
D. Connect the 398-5056 Probe to the pump wiring harness connector.
The probe must be used to prevent damage to the DCU and pump wiring harness connectors.
E. Measure the resistance between the following terminals affected DEF pump wiring harness connector and the affected 86-pin DCU wiring harness connector:
- Terminal 9 (PWM +) on the DEF pump wiring harness connector and Terminal 46 (PWM +) on the 86-pin DCU wiring harness connector.
- Terminal 8 (PWM -) on the DEF pump wiring harness connector and Terminal 26 (PWM -) on the 86-pin DCU wiring harness connector.
- Terminal 10 (PWM SIGNAL) on the DEF pump wiring harness connector and Terminal 24 (PWM SIGNAL) on the 86-pin DCU wiring harness connector.
Open Circuit
Result: There were less than 10 Ohms of resistance on all the DEF pump motor circuit wires.
Proceed to Test Step 2.
Result: There were more than 10 Ohms of resistance on any one of the DEF pump