SUPPORT AS 1474801 - Caterpillar

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,