Engine Controls - Tests W/O Codes - Gasoline: Introduction

Before diagnosing symptoms or intermittent faults, perform steps in appropriate BASIC TESTING and G - TESTS W/ CODES article (if applicable) in the ENGINE PERFORMANCE section. See BASIC TESTING and G - TESTS W/ CODES TABLES for specific model. Use this article to diagnose driveability problems that exist when a hard fault code is not present.

Symptom checks can direct the technician to malfunctioning component(s) for further diagnosis. A symptom should lead to a specific component, system test or an adjustment specification.

Use intermittent test procedures to locate driveability problems that do not occur while the vehicle is tested. These problems may noticeably affect driveability or cause Malfunction Indicator Light (MIL) to glow. Also use these test procedures if a soft (intermittent) trouble code was present but no problem is found during self-diagnostic testing.