Engine Controls - Tests W/O Codes: Introduction

CAUTION: When battery is disconnected, vehicle computer and memory systems may lose memory data. Driveability problems may exist until computer systems have completed a relearn cycle. See COMPUTER RELEARN PROCEDURES article in GENERAL INFORMATION section before disconnecting battery.

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.

NOTE: Some driveability problems may have been corrected by manufacturer with a revised PCM. Check with manufacturer for latest PCM.

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 appropriate SYSTEM/COMPONENT TESTING article. For specifications, see appropriate ADJUSTMENTS or SPECIFICATIONS article BELOW.