Engine Controls - Tests W/O Codes - Diesel: Introduction

Before diagnosing symptoms or intermittent faults, perform steps in BASIC DIAGNOSTIC PROCEDURES and appropriate TESTS W/CODES - DIESEL articles. 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.