Engine Control System - Testing & Engine Component Testing: Introduction
Before testing separate components or systems, perform all procedures listed in appropriate BASIC DIAGNOSTIC PROCEDURES article. Since many computer-controlled and monitored components will set a DTC if they malfunction, it is also recommended self-diagnostics be performed. See appropriate SELF-DIAGNOSTICS article.
NOTE:
Testing individual components does not isolate shorts or opens. Perform all voltage tests with a DVOM with a minimum 10-megohm input impedance, unless stated otherwise in test procedure. Use ohmmeter to isolate wiring harness shorts or opens.