Section 51 (Engine Controls - System & Component Testing - 6.6L): Introduction

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

NOTE: Unless specified otherwise, Sierra and Silverado information also applies to Cab & Chassis Sierra and Cab & Chassis Silverado.

Before testing separate components or systems, follow proper workflow. See DIAGNOSTIC STARTING POINT - ENGINE CONTROLS under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS - 6.6L SIERRA & SILVERADO - DIESEL article. If no Diagnostic Trouble Codes (DTC) are present and a no-start condition exists, proceed to NO-START DIAGNOSIS in BASIC DIAGNOSTIC PROCEDURES - 6.6L SIERRA & SILVERADO - DIESEL article. If no DTCs are present and a driveability condition exists, proceed to SYMPTOMS in TROUBLE SHOOTING - NO CODES - 6.6L SIERRA & SILVERADO - DIESEL article for diagnosis by symptom (i.e., ROUGH IDLE, ENGINE STALLS, etc.).

NOTE: Testing individual components does not isolate shorts or opens. Perform all voltage tests with a Digital Volt-Ohmmeter (DVOM) with a minimum 10-megohm input impedance, unless stated otherwise in test procedure. Use ohmmeter to isolate wiring harness shorts or opens.