Engine Controls - Self-Diagnostics: Introduction

NOTE: Prior to performing any diagnostic procedures, check for any applicable Technical Service Bulletins (TSBs).

To properly diagnose and repair this vehicle, follow DIAGNOSTIC STARTING POINT - ENGINE CONTROLS under SELF-DIAGNOSTIC SYSTEM. If no Diagnostic Trouble Codes (DTC) are present and a no-start condition exists, proceed to NO-START DIAGNOSIS in BASIC DIAGNOSTIC PROCEDURES - DEVILLE & SEVILLE article. If no DTCs are present and a driveability condition exists, proceed to TROUBLE SHOOTING - NO CODES - DEVILLE & SEVILLE article for diagnosis by symptom (i.e., ROUGH IDLE, ENGINE STALLS, etc.).