Subaru WRX & WRX STI Manuals 2013 Impreza WRX & WRX STI Owner's Manual | Page 270

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Starting and operating

ABS (Anti-lock Brake System)
The ABS system prevents the lock-up of
wheels which may occur during sudden
braking or braking on slippery road surfaces. This helps prevent the loss of
steering control and directional stability
caused by wheel lock-up.
When the ABS system is operating, you
may hear a chattering noise or feel a slight
vibration in the brake pedal. This is normal
when the ABS operates.
The ABS system will not operate when the
vehicle speed is below approximately 6
mph (10 km/h).

WARNING
Always use the utmost care in
driving – overconfidence because
you are driving with an ABS
equipped vehicle could easily lead
to a serious accident.

CAUTION
. The ABS system does not always
decrease stopping distance. You
should always maintain a safe
following distance from other

vehicles.
. When driving on badly surfaced
roads, gravel roads, icy roads, or
over deep newly fallen snow,
stopping distances may be longer for a vehicle with the ABS
system than one without. When
driving under these conditions,
therefore, reduce your speed and
leave ample distance from other
vehicles.
. When you feel the ABS system
operating, you should maintain
constant brake pedal pressure.
Do not pump the brake pedal
since doing so may defeat the
operation of the ABS system.

& ABS system self-check
Just after the vehicle is started, you may
feel on the brake pedal a vibration similar
to when the ABS operates, and you may
also hear the sound of the ABS working
from the engine compartment. This is
caused by an automatic functional test of
the ABS system being carried out and
does not indicate any abnormal condition.

& ABS warning light
Refer to “ABS warning light” F3-18.

Electronic Brake Force Distribution (EBD) system
The EBD system maximizes the effectiveness of the brakes by allowing the rear
brakes to supply a greater proportion of
the braking force. It functions by adjusting
the distribution of braking force to the rear
wheels in accordance with the vehicle’s
loading condition and speed.
The EBD system is an integral part of the
ABS system and uses some of the ABS
system’s components to perform its function of optimizing the distribution of braking force. If any of the ABS components
used by the EBD system malfunction, the
EBD system also stops working.
When the EBD system is operating, you
may hear a chattering noise or feel a slight
vibration in the brake pedal. This is normal
and does not indicate a malfunction.