Section 2779 (Engine Controls - Self-Diagnostics Introduction - CNG, Flex-Fuel & Gasoline): Introduction

WARNING: This page does not describe the selected car, but rather 32 other vehicles, including the 2003 Mercury Sable, 2003 Mercury Mountaineer, 2003 Mercury Marauder, 2003 Mercury Grand Marquis, and 2003 Lincoln Town Car. However, it is still accessible from the selected car via links, so may be relevant.

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.