Engine Controls - System & Component Testing: Introduction

Before testing separate components or systems, perform procedures in BASIC DIAGNOSTIC PROCEDURES article. Since many computer-controlled and monitored components set a Diagnostic Trouble Code (DTC) if they malfunction, also perform procedures in appropriate SELF-DIAGNOSTICS article.

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

NOTE: For ECM terminal identification, see PIN VOLTAGE/CIRCUIT RESISTANCE CHARTS article. For engine performance related component locations, see appropriate figure under COMPONENT LOCATIONS . For vacuum diagram identification, see VACUUM DIAGRAMS article.