A Important Preliminary Checks

Perform the Computers and Controls Systems Diagnostic Check before using the symptom tables. Refer to Diagnostic System Check-Computers and Controls Systems. Verify that all of the following conditions are true:
^ The powertrain control module (PCM) and malfunction indicator lamp (MIL) Service Engine Soon are operating correctly.
^ There are no diagnostic trouble codes (DTCs) stored.
^ The scan tool data is within the normal operating range, refer to Scan Tool Data List. Scan Tool Data, Normal Values and Definitions
^ Verify the customer concern. Locate the correct symptom in the table of contents. Inspect the items indicated under that symptom.