Initial Inspection and Diagnostic Overview

Four-Wheel Drive Systems

Special Tool(s):

Inspection and Verification
1. Verify the customer concern.
2. Inspect for obvious signs of mechanical or electrical damage.

Visual Inspection Chart:

3. If an obvious cause for an observed or reported concern is found, correct the cause (if possible) before proceeding to the next step.
4. If the cause is not visually evident, connect the diagnostic tool to the data link connector and select the vehicle to be tested from the diagnostic tool menu. If the diagnostic tool does not communicate with the vehicle:
^ check that the program card is correctly installed.
^ check the connections to the vehicle.
^ check the ignition switch position.
5. If the diagnostic tool still does not communicate with the vehicle, refer to the diagnostic tool operating information.
6. Carry out the diagnostic tool data link test. If the diagnostic tool responds with:
^ CAN circuit fault; all electronic control units no response/not equipped, refer to Information Bus.
^ No response/not equipped for 4WD control module, GO to Pinpoint Test B. Test B: No Communication With the 4-Wheel Drive (4WD) Control Module
^ System passed, retrieve and record the continuous diagnostic trouble codes (DTCs), erase the continuous DTCs, and carry out the self-test diagnostics for the 4WD control module.
7. If the DTCs retrieved are related to the concern, go to the Four-Wheel Drive (4WD) Control Module Diagnostic Trouble Code (DTC) Index.Diagnostic Trouble Code Tests and Associated Procedures
8. If no DTCs related to the concern are retrieved, carry out the Functional Test, and GO to Pinpoint Test A. Test A: Functional Test