Section 15 (Engine Controls - Basic Diagnostic Procedures): Introduction

WARNING: This page is about a different car, the 1999 Infiniti Q45, 1999 Infiniti I30, and 1999 Infiniti G20. However, it is still accessible from the selected car via links, so may be relevant.

NOTE: For basic diagnostic procedures on QX4, refer to Pathfinder in Nissan BASIC DIAGNOSTIC PROCEDURES article.

The following diagnostic steps will help prevent overlooking a simple problem. This is also where to begin diagnosis for a no-start condition. The first step in diagnosing any driveability problem is verifying customer complaint with a test drive under conditions problem reportedly occurred.

Before entering self-diagnostics, perform a careful and complete visual inspection. Most engine control problems result from mechanical breakdowns, poor electrical connections or damaged/misrouted vacuum hoses. Before condemning the computerized system, perform each test listed in this article.

NOTE: Perform all voltage tests using a Digital Volt-Ohmmeter (DVOM) with a minimum 10-megohm input impedance unless otherwise instructed in test procedure.