87743 Mercury GROMMET

Table 1
Diagnostic Trouble Codes for the DEF Pump
J1939 Code CDL Code Code Description
(code descriptions may vary) Comments
4374-5 3118-5 Aftertreatment #1 Diesel Exhaust Fluid Pump Motor Speed : Current Below Normal This code indicates low current to the DEF pump speed sensor.
The code is logged.
4374-6 3118-6 Aftertreatment #1 Diesel Exhaust Fluid Pump Motor Speed : Current Above Normal This code indicates high current to the DEF pump speed sensor.
The code is logged.
Follow the troubleshooting procedure in order to identify the root cause of the problem.
Table 2
Required Tools
Tool Part Number Part Description Qty
A 372-5260 Test Kit 1
Illustration 1 g03811009
Schematic diagram for the DEF pump motor
Illustration 2 g03811013
View of the pin locations for the DEF pump on the 86-pin DCU connector
(24) DEF pump signal
(26) DEF pump PWM return
(46) DEF pump PWM supply
Illustration 3 g03811015
Pin location on the DEF pump connector
(8) PWM return
(9) PWM supply
(10) PWM signal Complete the procedure in the order in which the steps are listed.
Table 3
Troubleshooting Test Steps Values Results
1. Inspect Electrical Connectors and Wiring
A. Inspect the 86-pin DCU connector.
B. Inspect the connector for the DEF pump.
C. Perform a 45 N (10 lb) pull test on each of the wires in the DCU connector and the connector for the DEF pump.
D. Check all of the wiring associated with the DEF pump for abrasions and pinch points.
Damaged wire or connector
Result: A damaged wire or damaged connector was not found.
Proceed to Test Step 2.
Result: A damaged wire or damaged connector was found.
Repair: Repair the damaged wire or the damaged connector.
Use the electronic service tool to clear all logged diagnostic codes. Verify that the repair eliminates the fault.
2. Determine the Diagnostic Code
A. Establish communication between the electronic service tool and the engine Electronic Control Module (ECM). Refer to Troubleshooting, "Electronic Service Tools"
B. Download the "Warranty Report" from the engine ECM before performing any troubleshooting or clearing diagnostic trouble codes.
C. Establish communication between the electronic service tool and the Dosing Control Unit (DCU) .
D. Look for active or logged codes.
Diagnostic Trouble Codes
Result: There is an active or logged 4374-5, 3118-5, 4374-6 or 3118-6 diagnostic code.
Proceed to Test Step 3.
3. Check for an Open Circuit in the Pump Electronic Tank Unit (PETU) Wiring Harness for the DEF Pump Motor Circuit
A. Turn the keyswitch to the OFF position for 2 minutes to allow the DEF pump to purge, reset the code, and reset the DCU.
B. Disconnect the PETU wiring harness from the DEF pump and the Diesel Exhaust Fluid Controller (DCU).
C. Connect the 398-5063 Break-out Connector to the DCU connector.
Connect the 398-5056 Break-out Connector to the pump connector.
The connectors must be used to prevent damage to the DCU and pump connectors.
D. Measure the resistance between terminal 9 (PWM +) on the DEF pump connector and terminal 46 (PWM +) on the 86 pin DCU connector.
E. Measure the resistance between terminal 8 (PWM -) on the DEF pump connector and terminal 26 (PWM -) on the 86 pin DCU connector.
F. Measure the resistance between terminal 10 (PWM SIGNAL) on the DEF pump connector and terminal 24 (PWM SIGNAL) on the 86 pin DCU connector.
Less than five Ohms
Result: All resistance measurements are less than five Ohms.
Proceed to Test Step 4.
Result: At least one of the resistance measurements is greater than five Ohms.
Repair: There is an open circuit in the harness. Repair the wiring or replace the harness.
Proceed to Test Step 6.
4. Check for Short Circuits in the PETU Wiring Harness for the DEF Pump Motor Circuit
A. Turn the keyswitch to the OFF position. The keyswitch must be OFF for 2 minutes to allow the DEF pump to purge, reset the code, and reset the DCU.
B. Disconnect the PETU wiring harness from the DEF pump and the DCU.
C. Connect the 398-5063 Break-out Connector to the DCU connector.
Connect the 398-5056 Break-out Connector to the pump connector.
Note: The connectors must be used to prevent damage to the DCU and pump connectors.
D. Measure the resistance between terminal 9 (PWM +) on the DEF pump connector and a known good chassis ground.
E. Measure the resistance between terminal 8 (PWM -) on the DEF pump connector and a known good chassis ground.
F. Measure the resistance between terminal 10 (PWM SIGNAL) on the DEF pump connector and a known good chassis ground.
Greater than 100k Ohms
Result: All resistance measurements are greater than 100k Ohms.
Proceed to Test Step 5.
Result: At least one of the resistance measurements is less than 100k Ohms.
Repair: There is a short circuit in the harness. Repair the wiring or replace the harness.
Proceed to Test Step 6.
5. Check for Short Circuits in the PETU Wiring Harness for the DEF Pump Motor Wiring
A. Turn the keyswitch to the OFF position. The keyswitch must be OFF for 2 minutes to allow the DEF pump to purge, reset the code, and reset the DCU.
B. Disconnect the PETU wiring harness from the DEF pump and the DCU.
C. Connect the 398-5063 Break-out Connector to the DCU connector.
Note: The 398-5063 Break-out Connector must be used to prevent damage to the DCU connector.
D. Measure the resistance between terminal 46 (PWM +) and all other pins in the