Engine Controls - Tests W/O Codes: Introduction

Before diagnosing symptoms or intermittent faults, perform steps in BASIC TESTING article and appropriate G -TESTS W/CODES article in the ENGINE PERFORMANCE section listed 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 the manufacturer with a revised Electronic Control Module (ECM). Check with manufacturer for latest ECM 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 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, see SYSTEM/COMPONENT TESTS article in the ENGINE PERFORMANCE section. For specifications, refer to appropriate ADJUSTMENTS article or SPECIFICATIONS article in the ENGINE PERFORMANCE section.