Section 42 (Engine Controls - System & Component Testing): Introduction

WARNING: This page is about a different car, the 2003 Lexus SC 430, 2003 Lexus LS 430, 2003 Lexus IS 300, 2003 Lexus GS 430, and 2003 Lexus GS 300. However, it is still accessible from the selected car via links, so may be relevant.

Before testing separate components or systems, perform procedures in BASIC DIAGNOSTIC PROCEDURES article. Since many computer-controlled and monitored components set a trouble code if they malfunction, also perform procedures in appropriate SELF-DIAGNOSTICS article. If no DTCs are present and a driveability condition exists, see TROUBLE SHOOTING - NO CODES 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.