SMART BRAKE SUPPORT (SBS) [REARWARD DETECTION]

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Outline

Caution

•  Tires for all four wheels must always be of the specified type and size. If tires other than the specified type and size are used, the smart brake support (SBS) [rearward detection] may not operate normally.

•  Do not mix tire types or use tires with significantly different wear patterns on the same vehicle. Use of inappropriate tires could result in the DSC and the smart brake support (SBS) [rearward detection] not operating normally.

Note

•  The smart brake support (SBS) [rearward detection] is designed to assist the driver. The driver's operation always takes priority even while the smart brake support (SBS) [rearward detection] is operating. For this reason, if the driver operates the brakes to avoid danger, the smart brake support (SBS) [rearward detection] operation is canceled.

•  In the following cases, turn off the smart brake support (SBS) [rearward detection] using the personalization features to prevent incorrect operation of the smart brake support (SBS) [rearward detection].

―  Chassis dynamometer is used

―  Vehicle is to tow another vehicle or be towed

―  Vehicle is traveling over grassy areas or off-road

•  If the vehicle is stopped by the operation of the smart brake support (SBS) [rearward detection], the smart brake support (SBS) [rearward detection] maintains the brakes for a certain period of time until the driver operates the vehicle.

•  The auto brake is released if any of the following operations is performed.

―  Accelerator pedal is depressed

―  Brake pedal is depressed

―  Electric parking brake is operated

―  Driver's seat belt is unfastened

―  Driver's door is opened

―  Selector lever position change (R to D or P)

―  10 min have elapsed since vehicle was stopped

•  The auto brake is released and the electric parking brake takes over if any of the following operations is performed.

―  Driver's seat belt is unfastened

―  Driver's door is opened

―  10 min have elapsed since vehicle was stopped

Structural view

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Function

Brake control

•  When the body control module (BCM) detects approaching vehicles and obstructions at the rear of the vehicle while reversing based on target information from the parking assist unit (ultrasonic) parking assist unit (optical), it sends a brake prefill request signal to the electronically controlled brake unit. Then, if the driver does not perform an avoidance maneuver and there is the possibility of a collision, it outputs a brake control (damage reduction braking) request signal to the electronically controlled brake unit to operate the brake control (damage reduction braking).

―  Brake control

•  If the body control module (BCM) determines that there is the possibility of a collision with a vehicle or obstruction at the rear or the vehicle while reversing, the electronically controlled brake unit operates the brake control (damage reduction braking) which applies the brakes on all four wheels.

Warning

•  The smart brake support (SBS) [rearward detection] operates when certain conditions are met, however, it is not a system that assures prevention of a collision.

•  There are limitations to the deceleration by the brake control (damage reduction braking). Always keep a safe distance from an obstruction at the rear of the vehicle and depress the brake pedal appropriately while verifying the safety of the surrounding area.

•  The smart brake support (SBS) [rearward detection] does not operate at a vehicle speed of less than approx. 2 km/h {1.2 mph} or more than approx. 8 km/h {5 mph}.

System conditions display

smart brake support (SBS) [rearward detection] display function table

Status				Smart brake support (SBS) OFF indicator light	i-ACTIVSENSE warning light	Active driving display	Multi-information display
SBS [rearward detection] system OFF Main power is switched ON (READY off or on)		SBS [rearward detection] system is stopped		ON	OFF	No display	No display	No display
SBS [rearward detection] system ON	Possibility of collision with vehicle or obstruction at rear	SBS [rearward detection] system is operating		OFF	OFF			No display
	Approx. 2 s have elapsed since vehicle was stopped by brake control (damage reduction braking) operation	•  Accelerator pedal is depressed •  Brake pedal is depressed •  Electric parking brake is operated •  Driver's seat belt is unfastened •  Driver's door is opened		OFF	OFF	No display	No display	No display
		Driver does not any of above reactions		OFF	OFF	No display		No display
	Abnormality occurred in SBS [rearward detection] system	SBS [rearward detection] system malfunction	Due to sensor	ON		No display
			Due to other cause	ON		No display		No display
		SBS [rearward detection] system function is stopped temporarily	Due to sensor	ON		No display
			Due to other cause	ON		No display	No display	No display

Caution

•  If a DTC is stored in the body control module (BCM) by the on-board diagnostic function, the smart brake support (SBS) [rearward detection] is inhibited depending on the cause of the malfunction.

•  If DTCs are stored in the electronically controlled brake unit, instrument cluster, parking assist unit (ultrasonic), parking assist unit (optical), the smart brake support (SBS) [rearward detection] is inhibited depending on the cause of the malfunction.

Note

•  With the smart brake support (SBS) system turned off, the smart brake support (SBS) [rearward detection] is also turned off.

•  If an abnormality occurs in the smart brake support (SBS) [rearward detection] system, a warning message is indicated on the center display. For the message content and verification method, refer to [CENTER DISPLAY] in the workshop manual.

System wiring diagram

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Operation

―  Switch the main power ON (READY on).

―  Selector lever position is in R position

―  Vehicle speed is between approx. 2 km/h {1.2 mph} to 8 km/h {5 mph}

―  No malfunction in smart brake support (SBS) [rearward detection] system

―  Smart brake support (SBS) [rearward detection] has not been turned off using personalization features

―  No malfunction in DSC system

―  No malfunction in parking assist unit (ultrasonic)

―  No major malfunction related to other vehicle behavior

Note

•  The smart brake support (SBS) [rearward detection] will operate even if the DSC OFF indicator light is turned on after the DSC operation is inhibited by operating the DSC OFF switch. If the smart brake support (SBS) [rearward detection] operates while the DSC has been inhibited, the DSC transitions to the permit condition and the DSC OFF indicator light turns off.

•  The smart brake support (SBS) [rearward detection] will operate even if the parking assist system operation is inhibited by operating the parking sensor OFF switch.

•  If ice, snow, or dirt is adhering to an ultrasonic sensor (rear side) the ultrasonic sensor (rear side) may not detect normally. As a result, the smart brake support (SBS) [rearward detection] may not operate normally.

•  The ultrasonic sensors may not detect normally depending on the travel or vehicle conditions. As a result, the smart brake support (SBS) [rearward detection] may not operate normally.

•  A ultrasonic sensor (rear side) may not detect depending on the direction in which an obstruction is approached, the shape of the obstruction and its surface material. As a result, the smart brake support (SBS) [rearward detection] may not operate normally.

Collision warning operation

•  When the body control module (BCM) detects approaching vehicles and obstructions at the rear of the vehicle based on target information (1) from the parking assist unit (ultrasonic), it sends a collision warning request signal (2) to the instrument cluster and the active driving display and, at the same time, it operates the brake prefill and the brake control. At the same time, the body control module (BCM) outputs (2) a warning sound signal to the notification and warning speaker (rear) to activate (3) the warning sound.

•  When the instrument cluster and the active driving display receive the collision warning request signal (2), a warning message (3) is displayed on the multi-information display and the windshield.

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Brake prefill operation

Solenoid valve operation table

Hydraulic circuit diagram

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Block diagram

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•  When the parking assist unit (ultrasonic) detect obstructions at the rear of the vehicle while reversing, they send a target signal (1) to the body control module (BCM).

•  When the body control module (BCM) receives the target signal, it sends a brake prefill request signal (2) to the electronically controlled brake unit.

•  When the electronically controlled brake unit receives the brake prefill request signal, it activates the pump motor (3). At this time, all of the solenoid valves are off and the brake fluid pressure generated by the pump motor is conducted (4) to the caliper pistons on each wheel.

•  By conducting the brake fluid pressure generated by the pump motor to the caliper pistons, the clearance between the brake pads and disc plates is maintained in a narrowed condition.

•  As a result, if the driver becomes aware of a vehicle or obstruction at the rear of the vehicle and depresses the brake pedal or the driver does not perform an avoidance maneuver and the brake control (damage reduction braking) is operated, braking force is generated immediately and the braking distance is reduced.

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Brake control (damage reduction braking) operation

Solenoid valve operation table

Hydraulic circuit diagram

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Block diagram

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•  After the brake prefill operation, if the driver does not perform an avoidance maneuver and the body control module (BCM) determines that there is the possibility of a collision, a brake control (damage reduction braking) request signal (1) is sent to the electronically controlled brake unit from the body control module (BCM).

•  When the electronically controlled brake unit receives the brake control (damage reduction braking) request signal, it energizes the linear control solenoid valve, switches the hydraulic circuits, and increases the brake fluid pressure. As a result, the brake control (damage reduction braking) operates (2).

•  While the brake control (damage reduction braking) is operating, a brake light signal (2) from the electronically controlled brake unit is sent to the electrical supply unit (ESU) at the same time.

•  A brake light status signal (3) is sent to the electronically controlled brake unit from the electrical supply unit (ESU) at the same time as the brake lights are turned on.

•  After the brake control (damage reduction braking) operates, a message is displayed on the multi-information display and the active driving display.

•   Thereafter, the driver needs to depress the brake pedal to maintain the vehicle in a stopped condition.

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