Engine Controls - Self-Diagnostics Introduction - CNG, Flex-Fuel & Gasoline: Introduction

NOTE: This article covers flex-fuel, gasoline & CNG vehicles. For Bi-Fuel (LPG and gasoline, or CNG and gasoline) vehicles, go to appropriate SELF-DIAGNOSTICS - BI-FUEL article.

Before proceeding with diagnostics, check for applicable Technical Service Bulletins (TSBs). If there are no applicable TSBs, perform QUICK TEST to identify Diagnostic Trouble Codes (DTCs). If DTCs exist, see DIAGNOSTIC TROUBLE CODE DEFINITIONS for diagnostic procedures. If no DTCs are present or only pass codes are found during self-diagnostics and symptom is present, proceed to TROUBLE SHOOTING - NO CODES - CNG, FLEX-FUEL & GASOLINE article for diagnosis by symptom.