Section 343 (ENGINE CONTROLS - SELF-DIAGNOSTICS - 4.8L, 5.3L & 6.0L - Flex Fuel & Gasoline): Introduction
WARNING: This page does not describe the selected car, but rather 13 other vehicles, including the 2003 Hummer H2, 2003 GMC Yukon XL, 2003 GMC Yukon, 2003 GMC Sierra, and 2003 GMC Cab & Chassis Sierra. However, it is still accessible from the selected car via links, so may be relevant.
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 - "C", "G", "H", "K", "N", "S" & "T" SERIES - FLEX FUEL & GASOLINE article. If no DTCs are present and a driveability condition exists, proceed to TROUBLE SHOOTING - NO CODES - 4.8L, 5.3L & 6.0L "C", "G", "H", "K", "N", "S" & "T" SERIES - FLEX FUEL & GASOLINE article for diagnosis by symptom (i.e., ROUGH IDLE, ENGINE STALLS, etc.).