BODY & CANOPY 4Z6876 - Caterpillar

Note: The diagram above is a simplified schematic of the ECM switch connections. The schematic is electrically correct, however, not all of the possible harness connectors are shown. For machines with serial number prefix (S/N: TFJ, TFK, TFN) refer to Electrical Schematic, UENR4020, "735C, 740C Ejector, and 745C Articulated Truck (T4F) Electric System". For machines with serial number prefix (S/N: LFJ, LFK, LFN) refer to Electrical Schematic, UENR4021, "735C, 740C Ejector, and 745C Articulated Truck (LRC) Electric System".Diagnostic Trouble Code Procedure
Prior to beginning this procedure, inspect the harness connectors that are involved in this circuit. Poor connections can often be the cause of a problem in an electrical circuit. Verify that all connections in the circuit are clean, secure, and in good condition. Check the wiring for pinch points or abrasions. Look for and repair areas that indicate wires are exposed. If a problem with a connection is found, correct the problem and verify that this diagnostic code is active before performing a troubleshooting procedure.
Table 3
Troubleshooting Test Steps Values Results
1. Identify Active FMI Code Associated With Sensor Circuit
Code present. FMI 2 diagnostic code, proceed to Test Step 2.
Begin Process For FMI 2 Troubleshooting HERE
2. Check The Retarder Lever Switch
A. Turn the key start switch and disconnect switch to the OFF position.
B. Disconnect the harness connector of the switch from the machine harness.
C. At the harness connector of the switch, check the continuity. Check the continuity from the ground return contact 6 to all other signal contacts. Activate each position of retarder lever switch. Refer to Table 2
The continuity check agrees with the information from Table 2. OK - The resistance that was measured is correct.
Proceed to Test Step 3.
NOT OK - One or more of the measurements Is not correct. The switch has failed.
Repair: Replace the switch.
STOP
3. Check For An Open In The Ground Return Circuit
A. The key start switch and the disconnect switch remain in the OFF position.
B. The harness connector of the switch remains disconnected from the machine harness.
C. At the machine harness connector for the switch, install a jumper wire from contact 6 (wire 200-BK(Black)) to the frame ground.
D. At the machine harness connector for the ground wire (wire 200-BK(Black)) measure the resistance.
The resistance should measure less than 5 ohms. OK - The resistance measures less than 5 ohms. The harness is correct.
Proceed to Test Step 4.
NOT OK - The resistance that is measured is greater than 5 ohms. There is an open in the harness.
Repair: Repair the harness or replace the harness.
STOP
4. Check The Machine Harness Of The Switch Circuit
A. The key start switch and the disconnect switch remain in the OFF position.
B. Remove the jumper wire from contact 6 (wire 200-BK(Black)) to the frame ground.
C. Reconnect the harness connector of the switch to the machine harness connector.
D. Place the shift lever into position 1.
E. Disconnect the machine harness connector J1 and J2 from the ECM.
F. Measure the resistance from wire 200-BK(Black) to all signal contacts. The signal contacts are contacts: J2-46, J2-47, and