Test Description
WARNING: This page is about a different car, the 2004 GMC Envoy XUV, 2004 GMC Envoy XL, 2004 GMC Envoy, and 2004 Chevrolet TrailBlazer. 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 |
|---|---|---|---|
| 1 |
IMPORTANT:
If the transfer case shift control switch is left between the 4HI and 4LO mode detents, the transfer case defaults to AWD mode. This is considered a characteristic of the system. Ensure the switch is within the proper detents. Did you perform the Diagnostic System Check - Transfer Case? |
Go to Step 2 | Go to Diagnostic System Check - Transfer Case |
| 2 |
|
Go to Step 4 | Go to Step 3 |
| 3 | Using a scan tool, observe the Commanded Mode Indicator Status. Is the transfer case in Auto 4WD, 4WD HI, 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 |
IMPORTANT:
After transfer case shift control module replacement and reprogramming, ensure all doors are closed and the key is out of the ignition, then open and close the doors again and wait 2 minutes to avoid incomplete programming or false communications DTCs. 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 |
|
Go to Step 2 | System OK |