GM Service Manual Online
For 1990-2009 cars only

Before using this section, perform the Powertrain On-Board Diagnostic (OBD) System Check and verify all of the following items:

    â€¢ The PCM and MIL (Service Engine Soon) are operating correctly.
    â€¢ There are no DTC(s) stored.
    â€¢ Scan tool data is within normal operating range, Refer to Engine Scan Tool Data List .
    â€¢ Verify the customer complaint and locate the correct symptom in the table of contents. Perform the procedure included in the symptom chart.