Ford Taurus, Руководство пользователя

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UNDERSTANDING AND TROUBLESHOOTING ELECTRICAL
SYSTEMS
Introduction
Most new vehicles are equipped with one or more on-board computers, like the
unit(s) installed on vehicles covered by this manual. These electronic components
(with no moving parts) should theoretically last the life of the vehicle, provided
nothing external happens to damage the circuits or memory chips.
While it is true that electronic components should never wear out, in the real
world malfunctions can, and often do, occur. It is also true that any computer-
based system is extremely sensitive to electrical voltages and cannot tolerate
careless or haphazard testing or service procedures. An inexperienced individual
can easily cause major damage looking for a minor problem by using the wrong
kind of test equipment or connecting test leads or connectors under improper
conditions. Always pay close attention to the circumstances when a test should be
performed. NEVER disconnect an ECM connector with the ignition switch ON.
When selecting test equipment, make sure the manufacturer's instructions state
that the tester is compatible with whatever type of electronic control system is
being serviced. Read all instructions carefully and double check all test points
before installing probes or making any test connections.
The following section outlines basic diagnosis techniques for dealing with
computerized automotive control systems. Along with a general explanation of
the various types of test equipment available to aid in servicing modern electronic
automotive systems, basic repair techniques for wiring harnesses and connectors
are given. Read the basic information before attempting any repairs or testing
any computerized system, to provide the background of information necessary in
order to avoid the most common and obvious mistakes that can cost both time
and money. Although the replacement and testing procedures are simple in
themselves, the systems are not, and unless one has a thorough understanding
of all components and their function within a particular computerized control
system, the logical test sequence these systems demand cannot be followed.
Minor malfunctions can make a big difference, so it is important to know how
each component affects the operation of the overall electronic system in order to
find the ultimate cause of a problem without replacing good components
unnecessarily. It is not enough to use the correct test equipment; the test
equipment must be used correctly.
Safety Precautions
z NEVER install or remove battery cables with the ignition switch ON or the engine
WARNING
Whenever working on or around any computer based microprocessor
controlsystem, always observe these general precautions to prevent
the possibility ofpersonal injury or damage to electronic components.
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18.11.2005 http://www.chiltondiy.com/content/8687/8687_6_1.html