Diagnostic Test

Ignition on.

With the scan tool, read DTCs in the Powertrain Control Module.

Are there any DTCs present? 

Yes 

1. Refer to the appropriate article in ENGINE PERFORMANCE and perform the applicable diagnostic procedure.
2. Perform TRANSFER CASE VERIFICATION TEST .

No 

1. Replace the Final Drive Control Module in accordance with the Service Information.
2. Perform TRANSFER CASE VERIFICATION TEST .