Engine Controls - System & Component Testing: Introduction
Before testing separate components or systems, perform procedures in appropriate BASIC DIAGNOSTIC PROCEDURES article. Since many computer-controlled and monitored components will set a Diagnostic Trouble Code (DTC) when they malfunction, also perform procedures in appropriate SELF-DIAGNOSTICS article.
NOTE:
Testing individual components does not isolate shorts or opens. Perform all voltage tests using a Digital Volt-Ohmmeter (DVOM) with a minimum 10-megohm input impedance, unless stated otherwise in test procedure. Use DVOM to isolate wiring harness shorts or opens.