Engine Controls - Tests W/O Codes: Introduction

Before diagnosing symptoms or intermittent faults, make sure all test procedures in BASIC TESTING article and TESTS W/CODES article have been performed. 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 Powertrain Control Module (PCM). Check with manufacturer for PCM application.

Symptom checks can direct the technician to malfunctioning components for further diagnosis. A symptom should lead to a specific component, system test or 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, refer to SYSTEM/COMPONENT TESTS article. For specifications, see ADJUSTMENTS or SPECIFICATIONS article.