Identifying Vehicle Equipment & System Problems
NOTE:
For connector terminal identification and wiring diagrams, see
BODY CONTROL COMPUTER - INTRODUCTION article. When directed to go to next step, disregard step if vehicle is not equipped with module being tested.
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 on left side of steering column. 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 BODY SYSTEM, then BODY COMPUTER. Scan tool will perform a CCD bus test. If scan tool displays BUS FAILED or NO RESPONSE, see appropriate VEHICLE COMMUNICATIONS article. If scan tool does not display BUS FAILED or NO RESPONSE, go to next step.
- Using scan tool, select SENSOR DISPLAY and read IGNITION VOLTAGE. If scan tool displays less than 10 volts, see appropriate VEHICLE COMMUNICATIONS article. If scan tool displays 10 volts or more, go to next step.
- 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. Systems listed are diagnosed using a scan tool. Malfunctions in these systems may occur separately or in various combinations. When diagnosing a system with many apparent problems, a sequence of tests may be required. At the beginning of each test, a note will indicate which test to perform first. After repairs, ensure problem(s) or failure(s) have been corrected.