Engine Controls - Tests W/O Codes: Introduction

Before diagnosing symptoms or intermittent faults, perform the Basic Diagnostic Procedures in the BASIC TESTING and the TESTS W/CODES articles in this section. 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 Electronic Control Unit (ECU). Check with manufacturer for latest chip or control unit 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. 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 specific testing procedures, see the article SYSTEM/COMPONENT TESTS article in this section. For related specifications, see the SPECIFICATIONS . For adjustment procedures, go to the ADJUSTMENTS article in this section.