Brake Assist System - Toyota sienna 2004 Service Manual

Vehicles with the vehicle stability con-
trol system—
The light comes on when the ignition key
is turned to the "ON" position. If the anti−
lock brake system and the brake assist
system work properly, the light turns off
after a few seconds. Thereafter, if either
of the systems malfunctions, the light
comes on again.
When the "ABS" warning light is on (and
the brake system warning light is off), the
anti−lock brake system, the brake assist
system, the traction control system and
the vehicle stability control system do not
operate, but the brake system still oper-
ates conventionally.
When the "ABS" warning light is on (and
the brake system warning light is off), the
anti−lock brake system does not operate
so that the wheels could lock up during
a sudden braking or braking on slippery
road surfaces.
04 SIENNA_U (L/O 0408)
If either of the following conditions
occurs, this indicates a malfunction
somewhere in the parts monitored by
the warning light system. Contact your
Toyota dealer as soon as possible to
service the vehicle.
D
The light does not come on when the
ignition key is turned to the "ON" posi-
tion, or remains on.
D
The light comes on while you are driv-
ing.
A warning light turning on briefly during
operation does not indicate a problem.
CAUTION
If the "ABS" warning light remains on
together with the brake system warn-
ing light, immediately stop your ve-
hicle at a safe place and contact your
Toyota dealer.
In this case, not only the anti−lock
brake system will fail but also the
vehicle will become extremely unsta-
ble during braking.
I n f o r ma t i o n P r o v i d e d b y :

BRAKE ASSIST SYSTEM

When you slam the brakes on, the
brake assist system judges as an emer-
gency stop and provides more powerful
braking for a driver who cannot hold
down the brake pedal firmly.
When you slam the brakes on, more pow-
erful braking will be applied. At this time,
you may hear a sound in the engine
compartment and feel the vibrations of the
brake pedal. This does not indicate a mal-
function.
Vehicles with the vehicle stability control
system—
The brake assist system becomes opera-
tive 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).
For an explanation of this system's warn-
ing light, see "Service reminder indicators
and warning buzzers" on page 167 in Sec-
tion 1−5.
2004 SIENNA from Aug. '04 Prod. (OM45422U)
375