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. Use this article to diagnose driveability problems if a hard fault code is not present or if vehicle is not equipped with a self-diagnostic system.

Symptom checks are intended to direct the technician to malfunctioning component(s) for further diagnosis. A symptom should lead to either specific component or system testing or an adjustment specification. Use intermittent test procedures to locate driveability problems which DO NOT  occur when the vehicle is being tested.