Lexus ES300 2003, Manual

Page: 256 / 377

STARTING AND DRIVING
242
BRAKE SYSTEM
The tandem master cylinder brake system is a hydraulic
system with two separate sub
−
systems. If either sub
−
system
should fail, the other will still work. However, the pedal will be
harder to press, and your stopping distance will be longer.
Also, the brake system warning light may come on.
CAUTION
Do not drive your vehicle with only a single brake
system. Have your brakes fixed immediately.
Brake booster
The brake booster uses engine vacuum to power
−
assist the
brakes. If the engine should quit while you are driving, you can
bring the vehicle to a stop with normal pedal pressure. There
is enough reserved vacuum for one or two stops but no more!
CAUTION
D Do not pump the brake pedal if the engine stalls.
Each push on the pedal uses up your reserved
vacuum.
D Even if the power assist is completely lost, the brakes
will still work. But you will have to push the pedal
hard, much harder than normal. And your braking
distance will be longer.
Anti
−
lock brake system
The anti
−
lock brake system is designed to help prevent
lock
−
up of the wheels during a sudden braking or braking
on slippery road surfaces. This assists in providing
directional stability and steering performance of the
vehicle under these circumstances.
Effective way to press the ABS brake pedal: When the
anti
−
lock brake system function is in action, you may feel the
brake pedal pulsating and hear a noise. In this situation, to
let the anti
−
lock brake system work for you, just hold the
brake pedal down more firmly. Do not pump the brake in a
panic stop. This will result in reduced braking performance.
The anti
−
lock brake system becomes operative after the
vehicle has accelerated to a speed in excess of approximately
10 km/h (6 mph). It stops operating when the vehicle
decelerates to a speed below approximately 5 km/h (3 mph).
Depressing the brake pedal on slippery road surfaces such as
on the manhole cover, the steel plate under the construction,
joints in the bridge, etc. on a rainy day tends to activate the
anti
−
lock brake system.