Section 4 (Engine Controls - Basic Testing): Introduction
WARNING: This page is about a different car, the 1995 Jaguar XJS, 1995 Jaguar XJR, and 1995 Jaguar XJ6. However, it is still accessible from the selected car via links, so may be relevant.
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 the customer's complaint with a test drive under the conditions the 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 with a Digital Volt-Ohmmeter (DVOM) with a minimum 10-megohm input impedance, unless specifically stated otherwise in test procedure.