Engine Controls - Tests W/O Codes: Introduction

NOTE: For testing procedures, see SYSTEM/COMPONENT TESTS article in the ENGINE PERFORMANCE section. For appropriate specifications, see ADJUSTMENTS or SPECIFICATIONS article in the ENGINE PERFORMANCE Section.

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

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

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

If no fault codes are present and driveability or customer complaints are present, perform functional test on ELR, EGR, and P-2 control on 5-cylinder or perform functional test on ELR and EGR on 6-cylinder. See appropriate FUNCTIONAL TEST under DIAGNOSTIC TESTS in TESTS W/CODES article in the ENGINE PERFORMANCE section.