HARNESS AS-SENSOR 1478178 - Caterpillar

The shift lever has three connectors.
8 Pin Connector
6 Pin Connector
4 Pin Connector
At the shifter, disconnect the 8-pin harness connector. The 6 pin harness connector remains connected to the shifter 6 pin connector. The shifter 4 pin connector remains jumpered between pins 3 and 4.
Refer to the schematic of the shifter and connect two jumper wires from the ECM connectors to frame ground in order to simulate each position of the shifter. Use the multimeter probe in order to make the connections. If a particular position is already suspect, begin with the wires for that position.
Monitor the status of the shifter on the Cat ET screen.Expected Result:As each combination of contacts are grounded, the Cat ET screen displays the corresponding shifter position.Results:
OK - As each combination of contacts are grounded, the Cat ET screen displays the corresponding shifter position. The ECM and harness appear to be working correctly.Repair: Replace the shifter.STOP
NOT OK - One of the combination of contacts is incorrect. The wiring harness or the ECM is not working correctly. Proceed to Test Step 4.Test Step 4. CHECK THE ECM.
Table 2
Transmission ECM Connector Pin Assignments    
Function     Wire Assignment     Transmission ECM Pin Assignments    
Forward     G750-BU     Connector J2, Pin 49    
Neutral     G763-PU     Connector J2, Pin 23    
Reverse     G755-GY     Connector J2, Pin 28    
First Gear     G768-GN     Connector J2, Pin 50    
Second Gear     G760-WH     Connector J1, Pin 41    
Third Gear     G761-YL     Connector J1, Pin 42    
Fourth Gear     G762-BR     Connector J1, Pin 43    
Open the machine service disconnect switch.
Based on the information in table 2 remove the corresponding wires from the Transmission ECM harness connectors. Also use the shifter schematic for reference. After removing all of the wires shown in table 2, place DT sockets into the connectors and wire the sockets so they can be connected to frame ground individually. Be sure that the wires cannot accidentally touch frame ground.
Close the machine service disconnect switch. Power up the machine with the key in the run position, and connect and start up the Cat ET service tool.
Use the schematic of the shifter, table 1 and table 2. Connect the two wires from the Transmission ECM harness connectors to frame ground in order to simulate each position of the shifter. If a particular position is already suspect, begin with the wires for that position.
Monitor the status of the shifter on the Cat ET screen.Expected Result:As each combination of contacts are grounded, the Cat ET screen displays the corresponding shifter position.Results:
OK - As each combination of contacts are grounded, the Cat ET screen displays the corresponding shifter position. The ECM is working properly. The wiring harness may have failed. Repair: Repair the wiring harness or replace the wiring harness.STOP
NOT OK - One of the combinations of contacts does not cause the proper status to be displayed. The ECM may have failed. Repair: Clean the contacts for the ECM