Mitsubishi 3000GT 1991 Service Manual page 729

SERVICE BRAKES -
PARTICULAR PHENOMENA OF THE
ANTI-LOCK BRAKING SYSTEM
Models equipped with the anti-lock braking system
phenomena from time to time, but none of these
are abnormal.
of the body or the steering wheel, when the
anti-lock braking system is activated by sudden
braking or by braking on a slippery road surface.
the anti-lock braking system is functioning nor-
mally.
(2) When the vehicle speed reaches approximately
6 km/h (4 mph) after the engine is started and
the vehicle starts off (for the first time), a
whining motor noise may be heard from the
engine compartment if the vehicle is traveling in
a quiet place, but this noise is simply the result
of a self-check being made of the anti-lock
braking system operation.
TROUBLESHOOTING METHODS
Problems related to the anti-lock braking system
(ABS) can be classified into two general categories:
problems in the electrical system and those in the
hydraulic system.
For problems in the electrical system, the self-
diagnosis function is built into the electronic control
unit (E.C.U.) causing the ABS warning light to
illuminate as a warning to the driver. In this instance,
checks can be made by using the multi-use tester
and oscilloscope.
Problems in the hydraulic system (poor braking,
etc.) can be located in the same way as for ordinary
brakes. There is, however, the necessity to check to
determine whether the problem is related to ordin-
ary brake components or to the components related
to the ABS. To make this check, use the multi-use
tester.
HOW TO USE THE TROUBLESHOOTING
FLOW CHART
(1) Using the flow chart, check the ABS warning
light light-up sequence. Read the diagnosis
codes and check the condition of braking opera-
tion.
(2) Following the check chart listed in the remedy
column, perform the checks. There are [Explana-
tion] and [Hint] in each check chart. Refer to
them when troubleshooting.
NOTE
ECU: Electronic control unit
HU: Hydraulic unit
MUT: Multi-use tester