Engine Controls - System & Component Testing: Introduction

NOTE: Testing individual components does not isolate shorts or opens. Perform all voltage tests using a Digital Volt-Ohmmeter (DVOM) with a minimum megaohm input impedance, unless stated otherwise in test procedure. Use ohmmeter to isolate wiring harness shorts or opens. For specific circuit diagrams to aid in diagnostic testing, see appropriate wiring diagram under ENGINE PERFORMANCE in WIRING DIAGRAMS.

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.