Nissan Primera P11. Manual - part 45
How to Perform Trouble Diagnoses for Quick
and Accurate Repair
INTRODUCTION
The ABS system has an electronic control unit to control major
braking functions. The control unit accepts input signals from
sensors and utilises the data to instantly drive the actuators. It is
essential that both input and output signals are correct and
stable. It is also important to check for conventional problems:
such as air leaks in booster lines, lack of brake fluid, or other
problems with the brake system.
It is much more difficult to diagnose a problem that occurs inter-
mittently rather than catastrophically. Most intermittent problems
are caused by poor electric connections or faulty wiring. In this
case, careful checking of suspicious circuits may help prevent
the unnecessary replacement of good parts.
A visual check may not be sufficient to find the cause of the
problems, so a road test should also be performed.
Before undertaking actual checks, take just a few minutes to talk
with a customer who approaches with a ABS complaint. The
customer is a very good source 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 brake problems on
an ABS controlled vehicle.
SEF233G
SEF234G
TROUBLE DIAGNOSES
BR-57