Test Description

WARNING: This page is about a different car, the 2005 GMC Yukon XL and 2005 GMC Yukon. 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: This step tests the functionality of the mode switch.
3: This step 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 Connector End View Reference: Transfer Case Control Connector End Views
1	Did you perform the Diagnostic System Check - Vehicle?	Go to Step 2	Go to Diagnostic System Check - Vehicle in Vehicle DTC Information
2	Install a scan tool. Start the engine. Place the transmission into Neutral. Set the parking brake. Use the scan tool in order to observe the Commanded Mode Indicator parameter while selecting each of the mode positions. Does the state change with each selection of the mode positions?	Go to Step 5	Go to Step 3
3	Use a scan tool in order to command through each mode of the mode selection switch. With a scan tool, command through all Commanded Mode Indicator parameter states. Does the Mode Indicator state change?	Go to Step 4	Go to Step 5
4	Replace the mode selection switch. Refer to Transfer Case Shift Control Switch Replacement . Did you complete the repair?	Go to Step 6	-
5	Replace the transfer case shift control module. Refer to Control Module References in Computer/Integrating Systems for replacement, setup, and programming. Did you complete the repair?	Go to Step 6	-
6	Use the scan tool in order to clear the DTCs. Operate the vehicle in order to determine if the symptom has been corrected. Is the symptom still present?	Go to Step 2	System OK