Test Description

WARNING: This page is about a different car, the 2002 GMC Yukon XL, 2002 GMC Yukon, 2002 Chevrolet Tahoe, 2002 Chevrolet Suburban, and 2002 Chevrolet Avalanche. However, it is still accessible from the selected car via links, so may be relevant.

The numbers below refer to the step numbers on the diagnostic table.

2: Tests the functionality of the Mode/Range buttons.
3: Tests the modules ability to operate the transfer case modes.

Transfer Case Shift Control Switch Inoperative

Step	Action	Yes	No
Schematic Reference: Transfer Case Control Schematics
1	Was the Transfer Case Diagnostic System Check performed?	Go to Step 2	Go to Diagnostic System Check - Transfer Case
2	IMPORTANT: NEUTRAL range will only be obtained by pressing and holding both the 2 HI and the 4 LO buttons simultaneously for 10 seconds. Refer to Circuit Description. Install a scan tool. Start the engine. Place the transmission into neutral (or clutch pedal depressed on manual transmission applications). Set the park brake. Observe the mode switch selected states on the scan tool while depressing and holding each of the Mode buttons. Does the state change with the press of any of the Mode buttons?	Go to Step 4	Go to Step 3
3	Use a scan tool in order to command through the modes of the Mode Switch. With a scan tool, command through all mode switch selected states. Does the Mode Indicator state change?	Go to Step 4	Go to Step 5
4	Replace the Mode/Range Switch. Refer to Transfer Case Shift Control Switch Replacement . Is the replacement complete?	Go to Step 6	-
5	Replace the transfer case shift control module. Refer to Transfer Case Shift Control Module Replacement . Is the replacement complete?	Go to Step 6	-
6	Use the scan tool in order to clear the DTCs. Operate the vehicle within the Conditions for allowing the symptom to re-occur. Does the symptom re-occur?	Go to Step 2	System OK