Engine Performance Self-Diagnostics: Introduction

To properly diagnose and repair this vehicle, follow TESTING PROCEDURE  under SELF-DIAGNOSTIC SYSTEM. If no trouble codes are present and a no start condition exists, proceed to appropriate BASIC DIAGNOSTIC PROCEDURES article. If no trouble codes are present and a driveability condition exists, proceed to TROUBLE SHOOTING - NO CODES article for diagnosis by symptom (i.e., ROUGH IDLE, ENGINE STALLS, etc.).