LINES GP-PRESSURE TEST 2219805 - Caterpillar

Illustration 1 g01191813
This diagnostic code is associated with the Rotary Switch (Variable Shift Control). The rotary switch is connected to three inputs of the ECM. Two contacts are open and the other contact is grounded during proper operation. If the power train ECM detects that more than one input is grounded, a circuit failure is present.Note: Ensure that the diagnostic code of CID 1521 FMI 02 is active before performing this procedure.
Table 1
Status of the Rotary Switch (Variable Shift Control)    
Switch Position     X972-GR
J2-34     X973-BU
J2-33     X974-BR
J2-32    
VSC #3 (Power)     Ground     Open     Open    
VSC #2 (Mid)     Open     Ground     Open    
VSC #1 (Economy)     Open     Open     Ground    Note: The following procedure can create other faults that can be detected by the power train ECM. Ignore these created faults and clear the created faults when the fault is corrected.Possible causes of this diagnostic code are listed:
There is a harness fault.
There is a failed switch.Test Step 1. CHECK FOR AN OPEN CIRCUIT
Turn the disconnect switch and the key start switch to the ON position.
Operate the machine.
Check the status of the CID 1521 FMI 02 while activating and deactivating each position of the auto/manual switch. Note the results. Note: If the code does NOT remain active during operation of the switch, this could indicate a possible open (which corresponds to the switch position) in the harness.
Turn the disconnect switch and the key start switch to the OFF position.
Disconnect the machine harness connectors from the power train ECM.
At the machine harness connector for the power train ECM, check the continuity to ground of the open contacts and the grounded contact for each position of the Rotary Switch (Variable Shift Control). Activate and deactivate each position of the Rotary Switch (Variable Shift Control).Expected Result:The continuity checks do not agree with the ground and open combinations.Results:
YES - The continuity checks do NOT agree with the ground and open combinations. The harness or the Rotary Switch (Variable Shift Control) is faulty. Proceed to Test Step 3.
NO - The continuity checks agree with the ground and open combinations. Proceed to Test Step 3.Test Step 2. CHECK THE ROTARY SWITCH (VARIABLE SHIFT CONTROL).
Disconnect the machine harness from the Rotary Switch (Variable shift Control).
Check the continuity to ground of the open contacts and the grounded contact for each position of the Rotary Switch. Activate and deactivate each position of the Rotary Switch. Expected Result:The continuity checks do not agree with the ground and open combinations.Results:
YES - The continuity checks do not agree with the ground and open combinations. The Rotary Switch is faulty.Repair: Repair the switch or replace the switch. Stop.
NO - The continuity checks agree with the ground and open combinations.Repair: Repair the machine harness or replace the machine harness. Stop.Test Step 3. CHECK FOR A SHORT TO THE +BATTERY.
At the machine harness connector for the power train ECM, check the continuity from each switch contact to the +Battery contacts.Expected Result:Continuity exists