Engine Controls - System & Component Testing: Introduction
Before testing separate components or systems, perform procedures in BASIC DIAGNOSTIC PROCEDURES article. Since the introduction of OBD-II, most all computer-controlled and monitored components set a Diagnostic Trouble Code (DTC) if they malfunction. Information for these components is covered in DIAGNOSTIC TESTS in appropriate SELF-DIAGNOSTICS article.
NOTE:
Testing individual components does not isolate a short or open circuit. Perform all voltage tests using a Digital Volt-Ohmmeter (DVOM) with a minimum 10-megohm input impedance, unless stated otherwise in test procedure.