Section 220 (ENGINE CONTROLS - BASIC DIAGNOSTIC PROCEDURES - 6.0L W/BiFuel & CNG ENGINES): Introduction

WARNING: This page is about a different car, the 2003 GMC Sierra, 2003 GMC Savana, 2003 Chevrolet Silverado, and 2003 Chevrolet Chevy Express. However, it is still accessible from the selected car via links, so may be relevant.

NOTE: Unless specified otherwise, Savana information also applies to Savana Special.

The following diagnostic steps help prevent overlooking simple problems. This is also where to begin diagnosis for a no start condition.

Before proceeding with basic diagnostic procedures, ensure testing procedure is followed, as some systems which may result in a no-start condition may cause a Diagnostic Trouble Codes (DTC) to be stored in the Powertrain Control Module (PCM). See DIAGNOSTIC STARTING POINT - ENGINE CONTROLS under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS - 6.0L CHEVY EXPRESS & SAVANA - BI-FUEL & CNG article or DIAGNOSTIC STARTING POINT - ENGINE CONTROLS under SELF-DIAGNOSTICS - 6.0L SIERRA & SILVERADO - BI-FUEL & CNG article.

If no-start condition still exists after checking and repairing all DTCs, perform a careful and complete visual inspection. Many problems result from mechanical breakdowns, poor electrical connections or damaged/misrouted vacuum hoses. See VISUAL INSPECTION under PRELIMINARY INSPECTION & ADJUSTMENTS. Before condemning the computerized system, perform each test listed in this article.

NOTE: Perform all voltage tests with a Digital Volt-Ohmmeter (DVOM) with a minimum 10-megohm input impedance, unless stated otherwise in test procedure.