803840 Mercury SWITCH, Neutral

Table 1
J1939 Code and Description CDL Code and Description Comments
4376-5
Aftertreatment #1 DEF Return Valve : Current Below Normal 3862-5
Aftertreatment #1 Diesel Exhaust Fluid Return Valve Solenoid : Current Below Normal This code indicates that there is problem with the Diesel Exhaust Fluid (DEF) pump reverting valve or the Pump Electronic Tank Unit (PETU) wiring harness.
4376-6
Aftertreatment #1 DEF Return Valve : Current Above Normal 3862-6
Aftertreatment #1 Diesel Exhaust Fluid Return Valve Solenoid : Current Above Normal This code indicates that there is problem with the DEF pump reverting valve or the PETU wiring harness.
4376-14
Aftertreatment #1 DEF Return Valve : Special Instruction 3862-14
Aftertreatment #1 Diesel Exhaust Fluid Return Valve Solenoid : Special Instruction This code indicates that there is problem with the DEF pump reverting valve or the PETU wiring harness.
4442-5
Aftertreatment #2 Diesel Exhaust Fluid Dosing Unit 1 Diverter Valve : Current Below Normal 5009-5
Aftertreatment #2 Diesel Exhaust Fluid Dosing Unit 1 Diverter Valve : Current Below Normal This code indicates that there is problem with the DEF pump reverting valve or the PETU wiring harness.
4442-6
Aftertreatment #2 Diesel Exhaust Fluid Dosing Unit 1 Diverter Valve : Current Above Normal 5009-6
Aftertreatment #2 Diesel Exhaust Fluid Dosing Unit 1 Diverter Valve : Current Above Normal This code indicates that there is problem with the DEF pump reverting valve or the PETU wiring harness.
4442-14
Aftertreatment #2 Diesel Exhaust Fluid Dosing Unit 1 Diverter Valve : Special Instruction 5009-14
Aftertreatment #2 Diesel Exhaust Fluid Dosing Unit 1 Diverter Valve : Special Instruction This code indicates that there is problem with the DEF pump reverting valve or the PETU wiring harness.
7536-5
Aftertreatment #1 DEF Dosing Unit #2 Diverter Valve : Current Below Normal 5008-5
Aftertreatment #1 Diesel Exhaust Fluid Return Valve Solenoid 2 : Current Below Normal This code indicates that there is problem with the DEF pump reverting valve or the PETU wiring harness.
7536-6
Aftertreatment #1 DEF Dosing Unit #2 Diverter Valve : Current Above Normal 5008-6
Aftertreatment #1 Diesel Exhaust Fluid Return Valve Solenoid 2 : Current Above Normal This code indicates that there is problem with the DEF pump reverting valve or the PETU wiring harness.
7536-14
Aftertreatment #1 DEF Dosing Unit #2 Diverter Valve : Special Instruction 5008-14
Aftertreatment #1 Diesel Exhaust Fluid Return Valve Solenoid 2 : Special Instruction This code indicates that there is problem with the DEF pump reverting valve or the PETU wiring harness.
7537-5
Aftertreatment #2 DEF Dosing Unit #2 Diverter Valve : Current Below Normal 5010-5
Aftertreatment #2 Diesel Exhaust Fluid Return Valve Solenoid 2 : Current Below Normal This code indicates that there is problem with the DEF pump reverting valve or the PETU wiring harness.
7537-6
Aftertreatment #2 DEF Dosing Unit #2 Diverter Valve : Current Above Normal 5010-6
Aftertreatment #2 Diesel Exhaust Fluid Return Valve Solenoid 2 : Current Above Normal This code indicates that there is problem with the DEF pump reverting valve or the PETU wiring harness.
7537-14
Aftertreatment #2 DEF Dosing Unit #2 Diverter Valve : Special Instruction 5010-14
Aftertreatment #2 Diesel Exhaust Fluid Return Valve Solenoid 2 : Special Instruction This code indicates that there is problem with the DEF pump reverting valve or the PETU wiring harness.
Table 2
Required Tools
Part Number Part Name Qty
372-5260 Test Kit 1
Illustration 1 g06100969
Illustration 2 g06300925
(1) Aftertreatment #2 .DCU #1 (yellow)
(2) Aftertreatment #2 .DCU #2 (red)
(3) Aftertreatment #2 DEF pump #2 (red)
(4) Aftertreatment #2 DEF pump #1 (yellow)
(5) Aftertreatment #1 DEF pump #2 (green)
(6) Aftertreatment #1 DEF pump #1 (blue)
(7) Aftertreatment #1 .DCU #2 (green)
(8) Aftertreatment #1 DCU #1 (blue)
Table 3
Troubleshooting Test Steps Values Results
1. Check the Pump Electronic Tank Unit (PETU) Wiring Harness for the Reverting Valve for 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 affected DEF pump and the affected DCU.
C. Connect the 398-5063 Probe to the DCU wiring harness connector.
D. Connect the 398-5056 Probe to the DEF pump wiring harness connector.
The probe must be used to prevent damage to the DCU and DEF pump wiring harness connectors.
E. Measure the resistance between the following terminals on the affected DEF pump connector and the affected 86-pin DCU wiring harness connector.
- Terminal 11 (reverting valve +) on the DEF pump wiring harness connector and Terminal 86 (reverting valve +) on the 86-pin DCU wiring harness connector.
- Terminal 12 (reverting valve -) on the DEF pump wiring harness connector and Terminal 65 (reverting valve -) on the 86-pin DCU wiring harness connector.
10 Ohms
Result: There were less than 10 Ohms of resistance on both of the reverting valve wires.
Proceed to Test Step 2.
Result: There were more than 10 Ohms of resistance on either wire for the reverting valve.
Repair: There is an open in the harness. Repair the wiring or replace the harness.
Verify that the repair eliminated the problem.
Proceed to Test Step 4.
2. Check the PETU Wiring Harness for the Reverting Valve for a Short Circuit
A. Turn the keyswitch to OFF.
B. Disconnect the PETU wiring harness from the affected DEF pump.
C. Disconnect the 86-pin wiring harness connector from the DCU.
D. Connect the 398-5056 Probe to the DEF pump wiring harness connector.
The probe must be used to prevent damage to the DEF pump wiring harness connector.
E. Measure the resistance between the following terminals on the affected DEF pump wiring harness connector and a known good chassis ground:
- Terminal 11 (reverting valve +) on the DEF pump wiring harness connector and a known good chassis ground.
- Terminal 12 (reverting valve -) on the DEF pump wiring harness connector and a known good chassis ground.
100 K Ohms
Result: There were more than 100K Ohms of resistance between the connector terminal and ground on both of the reverting valve wires.
Proceed to Test Step 3.
Result: There were less than 100K Ohms of resistance between the connector terminal and ground on either one of the reverting valve wires.
Repair: There is a short circuit in the harness. Repair or replace the wiring harness.
Verify that the repair eliminated the problem.
Proceed to Test Step