Engine Controls - Basic Diagnostic Procedures: Introduction

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 the 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.

Before proceeding with basic diagnostic procedures, ensure testing procedure is followed, as some systems which may result in a No-Start condition may cause a Diagnostic Trouble Codes (DTC) to be stored in the Powertrain Control Module (PCM).

On 2.0L, see DIAGNOSTIC TROUBLE CODE DEFINITIONS in SELF-DIAGNOSTICS - NEON & SX (CANADIAN) - 2.0L article.
On 2.4L, see DIAGNOSTIC TROUBLE CODE DEFINITIONS in SELF-DIAGNOSTICS - SRT-4 - 2.4L article.

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