Engine Controls - Self-Diagnostics: Introduction

Most engine control problems result from mechanical failures, poor electrical connections, or damaged vacuum hoses. Before condemning the computer system, perform checks and inspections covered in BASIC DIAGNOSTIC PROCEDURES article. Failure to do so may result in lost diagnostic time.

If no Diagnostic Trouble Codes (DTCs) are present, and driveability problems exist, proceed to TROUBLE SHOOTING - NO CODES article for diagnosis by symptom (i.e., rough idle, no start, etc.).