KEY GP-ELECTRONIC 5236599 - Caterpillar

Illustration 1 g00438565
Schematic for the Rocker Switch (Transmission Direction)The transmission direction switch has three inputs to the power train electronic control module (ECM). During normal operation, two of the inputs are open and the other input is grounded. The code is recorded when the status of two or more of the inputs for the transmission direction switch are grounded. Before you perform this procedure refer to table 1 in order to determine the connector and the contacts that correspond to the faulty circuit. The fault is set in 30 seconds and the fault is cleared in one second.Note: Ensure that the desired fault is active.Note: The following procedure can create other faults that may be detected by the power train ECM. Ignore these created faults and clear the created faults when the diagnostic code is corrected.
Table 1
Status of Direction Switch    
Switch Position    G755-GY Circuit
R Switch
J1-14    G763-PU Circuit
N Switch
J1-13    G750-BU Circuit
F Switch
J1-30    
R     Closed     Open     Open    
N     Open     Closed     Open    
F     Open     Open     Closed    Possible causes of the diagnostic code are listed:
There is a harness fault.
There is a failed switch.System Response:The machine response is listed:
The transmission will lock in neutral until a valid neutral switch position is sensed.Test Step 1. CHECK FOR AN OPEN CIRCUIT.
Ensure that the fault is active.
Disconnect the connector of the transmission direction switch from the machine harness.Expected Result:The active fault changes from "04" to "03".Results:
YES - The transmission direction switch or the switch harness is failed. Repeat Test Step 1 in order to verify the failure of the transmission direction switch.Repair: Repair the switch or replace the switch or the switch harness. Stop.
NO - The fault present indicator remains ON. The transmission direction switch is not the cause of this fault. Proceed to Test Step 2.Test Step 2. CHECK THE HARNESS CIRCUIT.This test checks the continuity of the entire harness circuit that is faulty. The transmission direction switch which was previously checked in Test Step 1 is included in this test.
Turn the key start switch and the disconnect switch to the OFF position.
Connect the transmission direction switch to the machine harness.
Disconnect the machine harness connector J1 from the power train ECM.
At the machine harness connector for the power train ECM, check the continuity to ground of the switch contacts for the transmission direction switch that is activated and switch that is not activated. Refer to table 1 for the correct switch status.Expected Result: The continuity check does NOT agree with table 1.Results:
YES - The continuity check does NOT agree with the previous table. The harness circuit is faulty. There is a short to ground in the machine harness between the power train ECM and the transmission direction switch.Repair: Repair the machine harness or replace the machine harness. Stop.
NO - The continuity check agrees with the previous table. The harness circuit is correct. It is unlikely that the power train ECM is faulty. Exit this procedure and perform the diagnostic