Engine Controls - System & Component Testing - V6 & V8: Introduction

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

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.

NOTE: When battery is disconnected on Sienna, power sliding doors will need to be initialized. See SLIDING DOOR INITIALIZATION PROCEDURE (SIENNA) in COMPUTER RELEARN PROCEDURES article in GENERAL INFORMATION. When battery is disconnected on Celica, power moon roof may need to be initialized for proper operation. See SUN ROOF INITIALIZATION (CELICA) in COMPUTER RELEARN PROCEDURES article in GENERAL INFORMATION.

Before testing separate components or systems, perform procedures in BASIC DIAGNOSTIC PROCEDURES - V6 & V8 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.