Engine Controls - Tests W/O Codes: Introduction

Before diagnosing symptoms or intermittent faults, perform steps in appropriate BASIC TESTING and TESTS W/CODES articles below. Use this article to diagnose driveability problems existing when a hard fault code is not present.

Basic tests, see: BASIC TESTING
Diagnostic code tests, see: TESTS W/CODES

NOTE: Some driveability problems may have been corrected by manufacturer with a revised computer control unit. Check with manufacturer for latest chip or computer application.

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

Use intermittent test procedures to locate driveability problems that DO NOT occur when the vehicle is being tested. These test procedures should also be used if a soft (intermittent) trouble code was present, but no problem was found during self-diagnostic testing.

NOTE: For component testing, see SYSTEM/COMPONENT TESTS article. For specifications, see the ADJUSTMENTS or the SPECIFICATIONS article.