Ford Corsar Repair Manual page 278

TROUBLE DIAGNOSES
1
KA24E
I
Senwrs
Control unit Actuators
@*&
SEF232G
How to Perform Trouble Diagnoses for Quick
and Accurate Repair
INTRODUCTION
The engine has an electronic control unit to control major
systems such as fuel control, ignition control, idle speed
control, etc. The control unit accepts input signals from sensors
and instantly drives actuators. It is essential that both kinds of
signals are proper and stable. At the same time, it is important
that there are no conventional problems such as vacuum leaks,
fouled spark plugs, or other problems with the engine.
It is much more difficult to diagnose a problem that occurs
intermittently rather than continuously. Most intermittent prob-
lems are caused by poor electric connections or faulty wiring. In
this case, careful checking of suspicious circuits may help
prevent the replacement of good parts.
A visual check only may not find the cause of the problems. A I
road test with a circuit tester connected to a suspected circuit
should be performed.
4
Before undertaking actual checks, take just a few minutes to talk
with
a
customer who approaches with a driveability complaint.
The customer is a very good supplier of information on such
problems, especially intermittent ones. Through the talks with
the customer, find out what symptoms are present and under
what conditions they occur.
Start your diagnosis by looking for "conventional" problems
first. This is one of the best ways to troubleshoot driveability
problems on an electronically controlled engine vehicle.