Initial Inspection and Diagnostic Overview

^ Before beginning any diagnosis or repair of COMPUTERIZED ENGINE CONTROLS, FUEL SYSTEMS or IGNITION SYSTEMS, always check TECHNICAL SERVICE BULLETINS. Many of the most complex and confusing problems associated with these systems are covered by the manufacturer's TSB's.

^ Before using this section you should start your diagnosis in the COMPUTERS AND CONTROL SYSTEMS section. Perform the ON-BOARD DIAGNOSTICS (extracting fault codes) which verifies that the Engine Control Module (ECM) and "CHECK ENGINE" light are operational and checks if any Diagnostic Trouble Codes (DTC) are stored. If any DTC's are stored in the ECM begin your diagnostics in the TESTING BY TROUBLE CODE section.

^ Always use the FLOW OF DIAGNOSIS for proper testing sequence.

^ Several of the following symptom procedures call for a careful visual/physical check. This step is very important - it can lead to correcting a problem without further checks and can save valuable time.