brake TOYOTA PRIUS PLUS 2012 Service Manual

284 2-4. Using other driving systems
PRIUS +_OM_OM47821E_(EE)
Canceling and resuming the speed control
Pulling the lever toward you
cancels the cruise control.
The speed setting is also can-
celed when the brakes are
applied.
Pushing the lever up
resumes the cruise control
and returns vehicle speed
to the set speed.
Resuming is available when
the vehicle speed is more
than approximately 40 km/h
(25 mph).

286 2-4. Using other driving systems
PRIUS +_OM_OM47821E_(EE)Example of constant speed cruising
When there are no vehicles ahead
The vehicle travels at the speed set by the driver. The desired vehicle-to-
vehicle distance can also be set by operating the vehicle-to-vehicle dis-
tance control.
Example of deceleration cruising
When the vehicle ahead is driving slower than the set speed
When a vehicle is detected running ahead of you, the system automati-
cally decelerates your vehicle. When a greater reduction in vehicle speed
is necessary, the system applies the brakes. A warning tone warns you
when the system cannot decelerate sufficiently to prevent your vehicle
from closing in on the vehicle ahead.
Example of follow-up cruising
When following a vehicle driving slower than the set speed
The system continues follow-up cruising while adjusting for changes in the
speed of the vehicle ahead in order to maintain the vehicle-to-vehicle dis-
tance set by the driver.
Example of acceleration
When there are no longer any vehicles ahead driving slower than
the set speed
The system accelerates until the set speed is reached. The system then
returns to constant speed cruising.

287 2-4. Using other driving systems
2
When driving
PRIUS +_OM_OM47821E_(EE)
Approach warning
When your vehicle is too close to a vehicle ahead, and sufficient
automatic deceleration via the cruise control is not possible, the dis-
play will flash and the buzzer will sound to alert the driver. An exam-
ple of this would be if another driver cuts in front of you while you are
following a vehicle. Apply the brakes to ensure an appropriate vehi-
cle-to-vehicle distance.
Warnings may not occur when
In the following instances, there is a possibility that the warnings
will not occur:
When the speed of the vehicle ahead matches or exceeds your
vehicle speed
When the vehicle ahead is traveling at an extremely slow speed
Immediately after the cruise control speed was set
At the instant the accelerator is applied
Selecting conventional constant speed control mode
Constant speed control mode differs from vehicle-to-vehicle distance
control mode. When constant speed mode is selected, your vehicle
will maintain a set speed regardless of whether or not there are other
vehicles in the lane ahead.

294 2-4. Using other driving systems
PRIUS +_OM_OM47821E_(EE)
CAUTION
Before using dynamic radar cruise control
Do not overly rely on vehicle-to-vehicle distance control.
Be aware of the set speed. If automatic deceleration/acceleration is not
appropriate, adjust the vehicle speed, as well as the distance between your
vehicle and vehicles ahead by applying the brakes etc.
Cautions regarding the driving assist systems
Observe the following precautions.
Failure to do so may cause an accident resulting in death or serious injury.
Assisting the driver to measure following distance
The dynamic radar cruise control is only intended to help the driver in
determining the following distance between the driver’s own vehicle and a
designated vehicle traveling ahead. It is not a mechanism that allows care-
less or inattentive driving, and it is not a system that can assist the driver in
low-visibility conditions. It is still necessary for driver to pay close attention
to the vehicle’s surroundings.
Assisting the driver to judge proper following distance
The dynamic radar cruise control determines whether the following dis-
tance between the driver’s own vehicle and a designated vehicle traveling
ahead is appropriate or not. It is not capable of making any other type of
judgement. Therefore, it is absolutely necessary for the driver to remain
vigilant and to determine whether or not there is a possibility of danger in
any given situation.
Assisting the driver to operate the vehicle
The dynamic radar cruise control has no capability to prevent or avoid a
collision with a vehicle traveling ahead. Therefore, if there is ever any dan-
ger, the driver must take immediate and direct control of the vehicle and
act appropriately in order to ensure the safety of all involved.

296 2-4. Using other driving systems
PRIUS +_OM_OM47821E_(EE)
CAUTION
When the sensor may not be correctly detecting the vehicle ahead
Apply the brakes as necessary when any of the following types of vehicles
are in front of you.
As the sensor may not be able to correctly detect these types of vehicles,
the approach warning (P. 287) will not be activated, and a fatal or serious
accident may result.
Vehicles that cut in suddenly
Vehicles traveling at low speeds
Vehicles that are not moving
Vehicles with small rear ends (trailers with no load on board etc.)
Motorcycles traveling in the same lane
Conditions under which the vehicle-to-vehicle distance control may
not function correctly
Apply the brakes as necessary in the following conditions as the radar sen-
sor may not be able to correctly detect vehicles ahead, and a fatal or serious
accident may result:
When water or snow thrown up by the surrounding vehicles hinders the
functioning of the sensor
When your vehicle is pointing upwards (caused by a heavy load in the lug-
gage compartment etc.)
When the road curves or when the lanes are narrow
When steering wheel operation or your position in the lane is unstable
When the vehicle ahead of you decelerates suddenly

298
2-4. Using other driving systems
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Driving assist systems
To help enhance driving safety and performance, the following sys-
tems operate automatically in response to various driving situations.
Be aware, however, that these systems are supplementary and
should not be relied upon too heavily when operating the vehicle.
ABS (Anti-lock Brake System)
Helps to prevent wheel lock when the brakes are applied suddenly, or if
the brakes are applied while driving on a slippery road surface
Brake assist
Generates an increased level of braking force after the brake pedal is
depressed when the system detects a panic stop situation
VSC (Vehicle Stability Control)
Helps the driver to control skidding when swerving suddenly or turning
on slippery road surfaces
TRC (Traction Control)
Helps to maintain drive power and prevent the drive wheels from spin-
ning when starting the vehicle or accelerating on slippery roads
EPS (Electric Power Steering)
Employs an electric motor to reduce the amount of effort needed to turn
the steering wheel

299 2-4. Using other driving systems
2
When driving
PRIUS +_OM_OM47821E_(EE)
VSC+ (Vehicle Stability Control+)
Provides cooperative control of the ABS, TRC, VSC and EPS.
Helps to maintain directional stability when swerving on slippery road
surfaces by controlling steering performance.
Hill-start assist control
P. 304
PCS (Pre-Crash Safety System) (if equipped)
P. 307
Emergency brake signal (if equipped)
When the brakes are applied suddenly, the stop lights automati-
cally flash to alert the vehicle behind.

300 2-4. Using other driving systems
PRIUS +_OM_OM47821E_(EE)
When the TRC/VSC/ABS systems are operating
The slip indicator light will flash
while the TRC/VSC/ABS sys-
tems are operating.
Sounds and vibrations caused by the ABS, brake assist, VSC and TRC
A sound may be heard from the engine compartment when the hybrid
system is started, just after the vehicle begins to move, if the brake pedal
is depressed forcefully or repeatedly, or 1-2 minutes after the hybrid sys-
tem is stopped. This sound does not indicate that a malfunction has
occurred in any of these systems.
Any of the following conditions may occur when the above systems are
operating. None of these indicates that a malfunction has occurred.
• Vibrations may be felt through the vehicle body and steering.
• A motor sound may be heard after the vehicle comes to a stop.
• The brake pedal may pulsate slightly after the ABS is activated.
• The brake pedal may move down slightly after the ABS is activated.
EPS operation sound
When the steering wheel is operated, a motor sound (whirring sound) may
be heard. This does not indicate a malfunction.

301 2-4. Using other driving systems
2
When driving
PRIUS +_OM_OM47821E_(EE)
Reduced effectiveness of the EPS system
The effectiveness of the EPS system is reduced to prevent the system from
overheating when there is frequent steering input over an extended period of
time. The steering wheel may feel heavy as a result. Should this occur,
refrain from excessive steering input or stop the vehicle and turn the hybrid
system off. The EPS system should return to normal within 10 minutes.
Electric power steering system warning light (warning buzzer)
P. 478
Operating conditions of emergency brake signal
When the following three conditions are met, the emergency brake signal
will operate:
The emergency flashers are off.
Actual vehicle speed is over 55 km/h (35 mph).
The brake pedal is depressed in a manner that cause the system to
judge from the vehicle deceleration that this is a sudden braking opera-
tion.
Automatic system cancelation of emergency brake signal
The emergency brake signal will turn off in any of the following situations:
The emergency flashers are turned on.
The brake pedal is released.
The system judges from the vehicle deceleration that is not a sudden
braking operation.

304
2-4. Using other driving systems
PRIUS +_OM_OM47821E_(EE)
Hill-start assist control
Hill-start assist control operating conditions
The system operates in the following situations:
• The shift position is in a position other than P.
• The parking brake is not applied.
• The accelerator pedal is not depressed.
Hill-start assist control cannot be operated while the slip indicator light is
illuminated.
Hill-start assist control helps to prevent the vehicle from rolling
backwards when starting on an incline or slippery slope.
To engage hill-start assist con-
trol, further depress the brake
pedal when the vehicle is
stopped completely.
A buzzer will sound once to
indicate the system is acti-
vated. The slip indicator will
also start flashing.