Engine Controls - Tests W/O Codes: Introduction

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

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

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.

Use intermittent test procedures to locate driveability problems that DO NOT occur when the vehicle is being tested.

Recommended procedures for each symptom will be indicated by a number(s) from 1 to 26, and may also contain specific instructions related to that number. To reduce diagnostic time, items should be checked in the order given. For a definition of each procedure, refer to SYMPTOM PROCEDURE DEFINITION in this article. Not all recommended procedures apply to all vehicles.

NOTE: For specific testing procedures, see I - SYSTEM/COMP TEST article. For specifications, see ADJUSTMENTS or SPECIFICATIONS article.