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: Determines the position of the Front Axle Switch.
3: Helps determine if the front axle will not engage.
4: 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
1	Was the Transfer Case Diagnostic System Check performed?	Go to Step 2	Go to Diagnostic System Check - Transfer Case
2	Turn the ignition ON, with the engine OFF. Request AWD with the mode switch Install a scan tool. Use the scan tool in order to read 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	Use the scan tool in order to read the Encoder Gear Position status. Is the mode switch selected indicator illuminated steadily in either Auto 4WD, 4WD HI, 4WD Low mode?	Go to Front Axle Will Not Engage	Go to Step 5
4	Use the scan tool in order to read 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 . Is the repair 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