Engine Controls - System/Component Tests: Introduction
Before testing separate components or systems, perform procedures in appropriate BASIC TESTING article in the ENGINE PERFORMANCE section. Since many computer-controlled and monitored components set a trouble code if they malfunction, also perform diagnostic procedures in the TESTS W/CODES - 1.8L article and/or the TESTS W/CODES - 2.0L/2.0L TURBO article in the ENGINE PERFORMANCE section.
NOTE:
Testing individual components does not isolate shorts or opens. Perform all voltage tests with a Digital Volt-Ohmmeter (DVOM) with a minimum 10-megohm input impedance, unless stated otherwise in test procedure. Use ohmmeter to isolate wiring harness shorts or opens.