Section 232 (Engine Controls - Trouble Shooting - No Codes - 4.8L, 5.3L & 6.0L): Introduction

WARNING: This page does not describe the selected car, but rather 19 other vehicles, including the 2003 Hummer H2, 2003 GMC Yukon XL, 2003 GMC Yukon, 2003 GMC Sierra, and 2003 GMC Savana Special. However, it is still accessible from the selected car via links, so may be relevant.

NOTE: Unless indicated otherwise, Sierra and Silverado includes Cab & Chassis Sierra and Cab & Chassis Silverado. Savana includes Savana Special and Savana Camper Special.

Before diagnosing symptoms or intermittent faults, follow proper workflow. See DIAGNOSTIC STARTING POINT - ENGINE CONTROLS under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS - 4.8L, 5.3L & 6.0L "C", "K" & "N" SERIES - FLEX FUEL & GASOLINE article or DIAGNOSTIC STARTING POINT - ENGINE CONTROLS under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS - 4.8L, 5.3L & 6.0L EXPRESS & SAVANA - GASOLINE article. If no Diagnostic Trouble Codes (DTC) are present and a no-start condition exists, proceed to NO-START DIAGNOSIS in BASIC DIAGNOSTIC PROCEDURES 4.8L, 5.3L & 6.0L "C", "G", "H", "K", "N", "S" & "T" SERIES - FLEX FUEL & GASOLINE article. If no DTCs are present and a driveability condition exists, diagnosis by symptom (i.e., ROUGH IDLE, ENGINE STALLS, etc.).

NOTE: Some driveability problems may have been corrected by manufacturer with a revised computer calibration chip or computer control unit. Check with manufacturer for latest chip or computer application.

Use intermittent test procedures to locate driveability problems that do not occur when the vehicle is being tested. These test procedures should also be used if a soft (intermittent) trouble code was present but no problem was found during self-diagnostic testing.

NOTE: For specific testing procedures, see SYSTEM & COMPONENT TESTING - 4.8L, 5.3L & 6.0L "C", "G", "H", "K", "N", "S" & "T" SERIES - FLEX FUEL & GASOLINE article. For specifications, see ON-VEHICLE ADJUSTMENTS - TRUCKS - EXCEPT TRACKER or appropriate SERVICE & ADJUSTMENT SPECIFICATIONS article.