5035144 JOHNSON COVER, UPPER MOUNT

Illustration 1 g00890690
Typical circuit schematic for the diagnostic moduleThe return wire may be connected to P1-3, P1-5, or P1-18.
Illustration 2 g01151099
Pin locations on ECM connector (P1-7) Input 4 (P1-18) Input sensor common 1Test Step 1. Inspect Electrical Connectors and Wiring
Thoroughly inspect the ECM vehicle harness connector J1/P1, the connectors, and the firewall bulkhead connectors. Refer to Troubleshooting, "Electrical Connectors - Inspect" for details.
Perform a 45 N (10 lb) pull test on each of the wires in the ECM connector that are associated with the torque limit switch.The wires are on the following terminals:
P1-7
P1-18
Check the ECM connector (allen head screw) for the proper torque. Refer to Troubleshooting, "Electrical Connectors - Inspect" for details.
Check the harness and the wiring for abrasion and for pinch points from the battery to the ECM. Then, check from the ignition key switch to the ECM.Refer to Illustration 2 for terminal locations for the ECM.Expected Result:All connectors, pins, and sockets are completely coupled and/or inserted, and the harness and wiring are free of corrosion, of abrasion or of pinch points.Results:
OK - Proceed to Test Step 2.
Not OK - Repair: Repair the wiring and connectors or replace the wiring or the connectors. Ensure that all of the seals are properly connected. Verify that the repair eliminates the problem.STOPTest Step 2. Check the Switch Circuit for the ECM
Illustration 3 g01151100
Pin locations on ECM connector (P1-7) Input 4 (P1-18) Input sensor common 1
Turn the ignition key switch to the OFF/RESET position.
Install a 140-2266 Cable breakout T to the ECM vehicle harness connector J1/P1.
Fabricate a jumper wire 100 mm (4 inch) long. Crimp a Deutsch pin to both ends of the wire.
Insert the jumper wire into terminal 7 of the breakout T. Connect the other end of the jumper wire to terminal 18 in the breakout T. Terminal 18 is input sensor common 1.
Connect Caterpillar Electronic Technician (ET) to the cab data link connector.
Turn the ignition key switch to the ON position.
Alternately remove the jumper wire and then insert the jumper wire from terminal 18. At the same time, monitor the status screen on Cat ET .Expected Result:The input status changes to "ON" with the jumper wire in place. The input status changes to "OFF" when the jumper wire is removed.Results:
OK - The ECM is functioning properly at this time. Proceed to Test Step 3.
Not OK - The ECM is not functioning properly.Repair: Perform the following repair:
Temporarily connect a test ECM.
Remove all jumpers and replace all connectors.
Recheck the system for active diagnostic codes.
Repeat the Test Step.
If the problem is resolved with the test ECM, reconnect the suspect ECM.
If the problem returns with the suspect ECM, replace the ECM.
Verify that the repair eliminates the problem.STOPTest Step 3. Insert a Jumper Wire at the Diagnostic Module
Turn the ignition key switch to the OFF/RESET position.
Reconnect the ECM vehicle harness connector J1/P1.
Fabricate a jumper wire 100 mm (4 inch) long. Crimp a Deutsch pin to both ends of the wire.
Insert the jumper wire between the two terminals at the diagnostic module.
Turn the ignition key switch to the ON position.
Alternately remove the jumper wire and then insert the jumper wire at the terminals on the diagnostic module. At the same time, watch the status screen on Cat ET.Expected Result:The input status changes to "ON" with the jumper wire in place. The input status changes to "OFF" when the jumper wire is removed.Results:
OK - The vehicle wiring is OK.Repair: Refer to Special Instruction, REHS1807, "Installation Guide for Diesel Particulate Filters" for troubleshooting the diagnostic module.STOP
Not OK - The problem is in the vehicle wiring between the ECM and the diagnostic module.Repair: Inspect the vehicle wiring and then repair the vehicle wiring. Otherwise, send the vehicle to the OEM dealer for repair. Verify that the original condition is resolved.STOP