Section 78 (Engine Controls - Basic Diagnostic Procedures - Trucks - Diesel): Introduction
WARNING: This page does not describe the selected car, but rather 10 other vehicles, including the 2002 Ford RV Cutaway, 2002 Ford Pickup, 2002 Ford F550 Super Duty, 2002 Ford F450 Super Duty, and 2002 Ford Excursion. However, it is still accessible from the selected car via links, so may be relevant.
WARNING:
Ensure negative battery cables are disconnected before disconnecting engine wiring harness. The Injector Driver Module (IDM) supplies 115-volts DC into each fuel injector connected to engine wiring harness. Severe electrical shock hazard exists. DO NOT pierce wires.
NOTE:
References to Econoline include Cutaway and RV Cutaway. References to F250-550 include Cab and Chassis.
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 symptom(s) 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.