Engine Controls - Basic Testing - 4-CYL: Introduction

NOTE: On Camry, an engine immobilizer system may be used. Engine immobilizer system is a theft deterrent system which disables the engine from starting by not allowing ignition system operation and fuel injector operation unless ignition key identification code matches identification code stored in the Engine Control Module (ECM). Engine immobilizer system is an option on LE models and standard feature on XLE models. For additional information on system operation and testing, see ENGINE IMMOBILIZER SYSTEMS article in ACCESSORIES/SAFETY EQUIPMENT section.

The following diagnostic steps will help prevent overlooking a simple problem. This is also where to begin diagnosis for a no-start condition.

The first step in diagnosing any driveability problem is verifying the customer's complaint with a test drive under the conditions problem reportedly occurred.

Before entering self-diagnostics, perform a careful and complete visual inspection. Most engine control problems result from mechanical breakdowns, poor electrical connections or damaged/misrouted vacuum hoses. Before condemning the computerized system, perform each test listed in this article.

NOTE: Perform all voltage tests with a Digital Volt-Ohmmeter (DVOM) with a minimum 10-megohm input impedance, unless stated otherwise in test procedure.