Intermittent Diagnosis: Introduction

Use this section to locate intermittent driveability problems that do not occur when the vehicle is being tested. These problems may cause a noticeable driveability problem or cause the "CHECK ENGINE" light to illuminate on some vehicles. Before attempting to diagnose an intermittent fault, ensure steps in BASIC TESTING and TESTS W/CODES (if applicable) have been performed.

Intermittent fault testing requires duplicating a circuit or component failure to identify the fault. These procedures may lead to the computer recording a fault code (on some systems), which may help in diagnosis.