Engine Controls - System & Component Testing - 4-Cylinder: Introduction

NOTE: Article applies to 2000 and 2001 MR2 models. On all other models, article applies only to 2001 models.

NOTE: Before performing system and component testing procedures, check for any related Technical Service Bulletins (TSBs).

WARNING: On Prius, read service precautions before proceeding with service procedure. See SERVICE PRECAUTIONS .

NOTE: References to California models apply to California emission vehicles, which may be verified by underhood Emission Control label. California emissions may be available in other states.

Before testing separate components or systems, perform procedures in BASIC DIAGNOSTIC PROCEDURES - 4-CYLINDER article. Since many computer-controlled and monitored components set a diagnostic trouble code if they malfunction, also perform procedures in appropriate SELF-DIAGNOSTICS article.

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 shorts or opens.