NISSAN 2012 Sentra - Manual (Page 258)

WARNING
Do not pump the brake pedal. Doing so
may
result in increased stopping
distances.
Self-test feature
The ABS includes electronic sensors, electric
pumps, hydraulic solenoids and a computer. The
computer has a built-in diagnostic feature that
tests the system each time you start the engine
and move the vehicle at a low speed in forward or
reverse. When the self-test occurs, you may hear
a “clunk” noise and/or feel a pulsation in the brake
pedal. This is normal and does not indicate a
malfunction. If the computer senses a malfunc-
tion, it switches the ABS off and illuminates the
ABS warning light on the instrument panel. The
brake system then operates normally, but without
anti-lock assistance.
If the ABS warning light illuminates during the
self-test or while driving, have the vehicle
checked by a NISSAN dealer.
Normal operation
The ABS operates at speeds above 3 - 6 MPH (5
- 10 km/h). The speed varies according to road
conditions.
When the ABS senses that 1 or more wheels are
close to locking up, the actuator rapidly applies
and releases hydraulic pressure. This action is
similar to pumping the brakes very quickly. You
may feel a pulsation in the brake pedal and hear a
noise from under the hood or feel a vibration from
the actuator when it is operating. This is normal
and indicates that the ABS is operating properly.
However, the pulsation may indicate that road
conditions are hazardous and extra care is re-
quired while driving.
The Vehicle Dynamic Control (VDC) system uses
various sensors to monitor driver inputs and ve-
hicle motion. Under certain driving conditions,
the VDC System helps to perform the following
functions:
● Controls brake pressure to reduce wheel
slip on one slipping drive wheel so power is
transferred to a non slipping drive wheel on
the same axle.
● Controls brake pressure and engine output
to reduce drive wheel slip based on vehicle
speed (traction control function).
● Controls brake pressure at individual wheels
and engine output to help the driver maintain
control of the vehicle in the following condi-
tions:
– understeer (vehicle tends to not follow
the steered path despite increased steer-
ing input)
– oversteer (vehicle tends to spin due to
certain road or driving conditions)
The VDC system can help the driver to maintain
control of the vehicle, but it can not prevent loss
of vehicle control in all driving situations.
When the VDC system operates, the indi-
cator in the instrument panel flashes so note the
following:
VEHICLE DYNAMIC CONTROL (VDC)
SYSTEM (if so equipped)
Starting and driving 5-27