Test Description

WARNING: This page is about a different car, the 2004 GMC Sierra, 2004 GMC Cab & Chassis Sierra, 2004 Chevrolet Silverado, and 2004 Chevrolet Cab & Chassis Silverado. 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 determines the position of the front axle switch.
3: This step helps determine if the front axle will not engage.
4: This step helps determine if the front axle will not disengage.

Transfer Case Shift Control Switch Indicators Flash Continuously 15 Seconds or More

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 - Transfer Case?	Go to Step 2	Go to Diagnostic System Check - Transfer Case
2	Turn the ignition ON, with the engine OFF. Install a scan tool. Using a scan tool, observe the Front Axle Switch status. Does the scan tool display the Front Axle Switch status as Locked?	Go to Step 4	Go to Step 3
3	Using a scan tool, observe the Encoder Gear Position status. Is the transfer case in 4WD HI or 4WD Low mode?	Go to Front Axle Will Not Engage	Go to Step 5
4	Using a scan tool, observe the Encoder Gear Position status. Is the transfer case in 2WD mode?	Go to Front Axle Will Not Disengage	Go to Step 5
5	Replace the transfer case shift control module. Refer to Transfer Case Shift Control Module Replacement and Transfer Case Control Module Reprogramming . 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