LEVER 6W7373 - Caterpillar

Table 1
Diagnostic Trouble Codes for the DEF Control Module Power Supply
J1939 Code CDL Code Code Description
(code descriptions may vary) Comments
5966-5 3965-5 Aftertreatment #1 Diesel Exhaust Fluid Dosing Control Unit : Current Below Normal A low current condition has been detected on the keyswitch circuit between the engine ECM and the DCU.
5966-6 3965-6 Aftertreatment #1 Diesel Exhaust Fluid Dosing Control Unit : Current Above Normal A high current condition has been detected on the keyswitch circuit between the engine ECM and the DCU.
6309-5 3966-5 Aftertreatment #1 Diesel Exhaust Fluid Dosing Control Unit (KSW sinking dout) : Current Below Normal A low current condition has been detected on the keyswitch circuit between the engine ECM and the DCU.
6309-6 3966-6 Aftertreatment #1 Diesel Exhaust Fluid Dosing Control Unit (KSW sinking dout) : Current Above Normal A high current condition has been detected on the keyswitch circuit between the engine ECM and the DCU.
Illustration 1 g06206536
Schematic for the DCU electrical power supply circuit
Not all connectors are shown. Refer to the electrical schematic.
Table 2
Troubleshooting Procedure for the DCU Keyswitch Signal
Troubleshooting Test Steps Value Results
1. Inspect Electrical Connectors and Wiring
A. Turn the keyswitch to the OFF position.
B. Inspect the connectors in the circuit for the DEF control module.
Refer to Troubleshooting, "Electrical Connectors - Inspect" for details.
C. Perform a 45 N (10 lb) pull test on each of the wires that are associated with the DEF control module power circuit.
D. Check the screw for the P1 ECM connector for correct torque of 6 N m (53 lb in).
E. Check all the wiring associated with the DEF Control module power circuit for abrasions and pinch points.
Damaged wire or connector
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.
Use the electronic service tool to perform the "Aftertreatment System Functional Test" to verify that the repair eliminates the fault.
Result: A damaged wire or damaged connector was not found.
Proceed to Test Step 2.
2. Determine the Code
A. Establish communication between the electronic service tool and the Electronic Control Module (ECM). Refer to Troubleshooting, "Electronic Service Tools", if necessary.
B. Download the "Warranty Report" from the ECM before troubleshooting or clearing any diagnostic trouble codes.
C. Determine the diagnostic trouble code that is active.
Diagnostic Trouble Code
Result: