Identifying Vehicle Equipment & System Problems

NOTE: For connector terminal identification wiring diagrams, see BODY CONTROL COMPUTER - INTRODUCTION article.

NOTE: Perform a visual inspection before proceeding with this test.

Connect scan tool to Data Link Connector (DLC). DLC is a 16-pin connector located under left side of dash, to left of steering wheel. Turn ignition switch to ON position. If scan tool display is not blank, go to next step. If scan tool display is blank, see appropriate VEHICLE COMMUNICATIONS article.
Using scan tool, select SYSTEM MONITORS, then CCD BUS TEST. Scan tool will perform a CCD bus test. If scan tool displays BUS OPERATIONAL, go to next step. If scan tool displays any message except BUS OPERATIONAL, see appropriate VEHICLE COMMUNICATIONS article.
Using scan tool, select READ DTCs. If any Diagnostic Trouble Codes (fault messages) are present, go to appropriate fault message. If no fault messages are present, identify customer complaint. See following list for possible fault messages and customer complaint symptoms. Problems listed are diagnosed using a scan tool. These problems may occur separately or in various combinations. When diagnosing a system with many apparent problems, a sequence of tests may be required. After repairs, ensure problem(s) or failure(s) have been corrected.