Did you perform the Diagnostic System Check - Transfer Case?

Go to Step 2

Go to Diagnostic System Check - Transfer Case

2

1. Turn the ignition ON, with the engine OFF.
2. Ensure that the vehicle is in 4WD mode
3. Install a scan tool.
4. 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 3

Go to Front Axle Will Not Engage

3

1. Change the transfer case mode from 4WD to AWD mode.
2. 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 6

4

1. Change the transfer case mode back from AWD to 4WD mode.
2. Drive the vehicle for a short test drive while observing the Transfer Case Data List.
3. Note the values of the Front and Rear Propshaft Speed at a set speed.
4. Compare the Front and Rear Propshaft speed previously noted at the same speeds.

Are the RPM values approximately equal at the same speeds?

Go to Step 6

Go to Step 5

Inspect the front axle and transfer case for a mechanical malfunction. Repair or replace components as needed.

Did you complete the repair?

Go to Step 7

--

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 communication DTCs.

Replace the transfer case shift control module. Refer to Transfer Case Shift Control Module Replacement and Transfer Case Shift Control Module Reprogramming .

Did you complete the repair?

Go to Step 7

--

1. Use the scan tool in order to clear the DTCs.
2. Operate the vehicle within the conditions for the symptom to occur.

Does the symptom occur?

Go to Step 2

System OK