Test Description

WARNING: This page is about a different car, the 2007 Hummer H2. 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
2	Install a scan tool. Start the engine. Place the transmission into Neutral. Set the park brake. Observe the Mode Switch Selected parameter on the scan tool while selecting each of the mode positions on the switch. Does the state change with the selection of each of the mode positions?	Go to Step 5	Go to Step 3
3	Test the switch signal and 5-volt reference circuits for an open, high resistance, short to ground, and short to voltage. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition?	Go to Step 6	Go to Step 4
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 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