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:

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