PIN-TRACK MASTER 3408907 - Caterpillar

Illustration 1 g01376083
"Transmission Auto/Manual" switch connections
The "transmission auto/manual" switch is a two pole, double-throw switch. One pole is used to provide two switch to ground inputs to the ECM in order to indicate the status of the switch. The other pole of the switch is not used for operations of the ECM.During normal operation, one of the inputs is not connected to ground and the other input is connected to ground through the switch contacts. An internal pull-up voltage is present at the ECM switch inputs. When the input is grounded through the switch, the ECM detects the ground signal.The FMI 04 diagnostic code is activated by the ECM when both of the inputs are showing a ground signal at the same time.The conditions that could cause the ECM to activate this diagnostic code are listed below:
The switch has failed.
There is a short to a ground source in one or both of the switch input circuits.
The ECM has failed. This is unlikely.Note: Before performing this procedure, inspect the harness connectors that are involved in the circuit. Poor connections can often be the cause of a problem in an electrical circuit. Verify that all connections in the circuit are clean, that all connections are secure and that all connections are in good condition. If a problem with a connection is found, correct the problem and verify that this diagnostic code is active before performing this procedure. Note: The following test procedure may cause other diagnostic codes to be activated. Ignore these created diagnostic codes and clear the diagnostic codes when the problem has been corrected.Test Step 1. CHECK THE SWITCH
Table 1
States of Contact for the Transmission Auto/Manual Switch
Switch Position N/O Input J2-47 (wire U726-GY(Grey)) N/C Input J2-52 (wire U725-GN(Green))
Autoshift OFF Open(1) Closed(2)
Autoshift ON Closed Open
(1) Open to ground (wire A202-BK(Black)).
(2) Closed to ground (wire A202-BK(Black)).
Turn the key start switch and the disconnect switch to the OFF position.
Disconnect the machine harness connector from the switch.
With the switch in the ON position, measure the resistance from the common contact of the switch (2) to the input contact of the switch (1). Compare the measurement of the switch to the table above.
With the switch in the ON position, measure the resistance from the common contact of the switch (2) to the input contact of the switch (3). Compare the status of the switch to the table above.
Move the switch to the OFF position and repeat Steps "C" and "D". Expected Result:The measurements of resistance for each of the positions of the switch agree with the status shown in the table at the beginning of this test step.Results:
YES - All of the resistance checks for the switch are correct in each switch position according to the table above. The switch is working correctly. Proceed to Test Step 2.
NO - The states of the switch are not correct according to the table. The switch has failed.Repair: Replace the "Transmission Auto/Manual" switch. After the switch is replaced, verify that the switch operation is correct before operating the machine.STOPTest