The scan tool provides the following capabilities:

Make sure the scan tool contains the latest diagnostic information before attempting to communicate with the transfer case shift control module. To use the scan tool, connect it to the Data Link Connector (DLC) and turn the ignition switch to the RUN position. The scan tool reads the Class 2 serial data sent from the transfer case shift control module connector C1 terminal E9 to the DLC terminal 2.

The Transfer Case Scan Tool Data List contains all the ATC related parameters that are available on the scan tool. The list is arranged in the order as they appear on the scan tool.

Use the Transfer Case Scan Tool Data List only after the following is determined:

Scan tool values from a properly operating system may be used for comparison with the automatic transfer case system you are diagnosing. The Transfer Case Scan Tool Data List represents values recorded under the following conditions:

Important: Make sure the scan tool that you are using is functioning properly. Use of a malfunctioning scan tool can result in misdiagnosis and unnecessary parts replacement.

Only the parameters listed below are referenced in this service manual for use in diagnosis. If all values are within the typical range described below, refer to Intermittents and Poor Connections for diagnosis.