SMART CITY BRAKE SUPPORT [FORWARD] (SCBS F)

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Purpose

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 City Brake Support (SCBS) system 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 Smart City Brake Support (SCBS) system not operating normally.

•  Always use tires for all wheels that are of the specified size, and the same manufacture, brand, and tread pattern. In addition, do not use tires with significantly different wear patterns on the same vehicle. If such improper tires are used, the Smart City Brake Support (SCBS) system may not operate normally.

Note

•  The Smart City Brake Support (SCBS) system is designed to assist the driver. The driver's driving operation always takes priority even while the Smart City Brake Support (SCBS) system is operating. For this reason, if the driver operates the steering wheel, accelerator pedal or brakes to avoid danger, the Smart City Brake Support (SCBS) system operation is canceled.

•  Turn off the Smart City Brake Support (SCBS) system to prevent mistaken operation when the vehicle is running on a chassis roller.

Function

―  Brake prefill

•  If the laser sensor determines that the vehicle is approaching a vehicle or obstruction ahead, the DSC HU/CM implements brake prefill by pressurizing the brake fluid and eliminating the play between the brake pads and disc plates. As a result, if the driver becomes aware of the situation ahead and depresses the brake pedal, immediate brake force can be obtained.

―  Brake control (SCBS brake)

•  If the laser sensor determines that the vehicle is in danger of colliding with a vehicle or obstruction ahead, the system warns the driver using a warning sound (Smart City Brake Support (SCBS)), and warning indications in the active driving display* and, at the same time, the DSC HU/CM activates the brake control by applying the brakes on all four wheels automatically.

Warning

•  The Smart City Brake Support (SCBS) system operates when a certain number of conditions is met, however, it is not a system which guarantees collision prevention.

•  There are limitations to the deceleration ability by the brake control (SCBS brake), and the system may be unable to decelerate sufficiently to avoid hitting the vehicle ahead if the vehicle ahead applies the brakes suddenly or another vehicle cuts into the driving lane, which could result in an accident. Always verify the safety of the surrounding area and depress the brake pedal while keeping a safe distance from the vehicle ahead.

•  The brake prefill and brake control (SCBS brake) does not operate at a vehicle speed of less than approx. 4 km/h {2 mph}, a vehicle speed of approx. 30 km/h {19 mph} or more, and while the vehicle is reversing.

•  Do not apply stickers to the windshield surface around the sensor. Application of even transparent stickers will cause the Smart City Brake Support (SCBS) system to operate incorrectly, which could result in an accident.

Note

•  If a malfunction occurs in the Smart City Brake Support (SCBS) system, a warning message is indicated in the center display. For the message content and verification method, refer to the [CENTER DISPLAY]. (SeeCENTER DISPLAY [WITH CENTER DISPLAY].)

Construction/Operation

•  The laser sensor installed on the upper area of the windshield detects a vehicle running ahead within approx. 6 m {20 ft} from the laser sensor.

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System wiring diagram (Without Mazda Radar Cruise Control (MRCC) system)

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System wiring diagram (With Mazda Radar Cruise Control (MRCC) system)

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―  The engine is running.

―  The center display in the instrument cluster does not indicate that the system requires inspection.

―  The vehicle speed is between approx. 4 km/h {2 mph} to 30 km/h {19 mph}.

―  The Smart City Brake Support (SCBS) system is not turned off.

―  The DSC is not malfunctioning.

―  The driver is not deliberately performing driving operations (accelerator pedal, steering wheel, and braking operations).

Note

•  The Smart City Brake Support (SCBS) system will operate even if the DSC OFF indicator light is illuminated after the DSC is stopped by operating the DSC OFF switch. If the Smart City Brake Support (SCBS) system operates while the DSC has been stopped, the DSC becomes operational and the DSC OFF indicator light turns off.

•  The Smart City Brake Support (SCBS) detects a vehicle ahead by emitting a near infrared laser beam and receiving the beam reflected off the reflector or the vehicle ahead, and then using it for the measurement. Consequently, the Smart City Brake Support (SCBS) may not operate under the following conditions:

―  Reflection of laser sensor is poor due to the shape of the vehicle ahead.

―  The vehicle ahead is significantly dirty.

―  Under bad weather condition such as rain, fog, and snow.

―  When the window washer is being used or the windshield wipers are not used when it is raining.

―  The windshield is dirty.

―  The steering wheel is turned completely left or right, or the vehicle is accelerated rapidly and comes close to the vehicle ahead.

―  Trucks with low loading platforms, vehicles traveling at extremely low speeds, and vehicles with high profile.

―  Vehicles with certain shapes such as a vehicle carrier.

•  Under the following conditions, the Smart City Brake Support (SCBS) system may not operate normally:

―  Heavy luggage is loaded in the luggage compartment or on the rear seat.

―  When there is the possibility of a partial contact with a vehicle or obstruction ahead.

―  When driving on continuously curving roads, entering and existing curves, and unstable driving due to a vehicle accident or breakdown in a driving lane.

―  Elongated luggage or cargo is loaded onto installed roof rails and covers the laser sensor.

―  Exhaust gas from the vehicle ahead, sand, snow, and water vapor rising from manholes and grating, and water splashed into the air.

•  In the following cases, if the laser sensor determines that there is a vehicle ahead and the Smart City Brake Support (SCBS) system may operate:

―  Object on the road at the entrance to a curve.

―  Vehicles passing in the opposite lane while making a curve.

―  Metal objects, bumps, or protruding objects on the road.

―  When passing through a toll gate.

―  When passing under a vinyl curtain or flag.

―  Plastic objects such as pylons.

―  Two-wheeled vehicles, pedestrians, animals or standing trees.

―  There is fogging on the inner surface of the windshield (where the near infrared laser beam is emitted).

•  Operate the air conditioning system to defrost the windshield around the laser sensor first before starting to drive.

―  There is/are fogging/water drops on the outer surface of the windshield (where the near infrared laser beam is emitted).

•  Operate the wiper system to remove the fogging/water drops on the windshield.

Collision warning operation

•  When the laser sensor detects that the vehicle is approaching a vehicle ahead, it outputs a collision warning request signal (1) to the instrument cluster.

•  The instrument cluster turns the transistor on (2) based on the collision warning request signal.

•   When the transistor turns on, a ground circuit with the alarm is established and the alarm sounds (3) and, in the same time, a warning message is indicated in the active driving display (if equipped the active driving display). (See Smart City Brake Support [Forward] (SCBS F) display function.)

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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 laser sensor detects that the vehicle is approaching a vehicle ahead, it outputs a brake prefill request signal (1) to the DSC HU/CM.

•  The DSC HU/CM operates the pump motor (2) to activate the pump so that the brake fluid pressure is lead to the caliper piston (3) and the brake pads are kept near the disc plate.

•  As a result, if the driver realizes that he/she is approaching a vehicle ahead and depresses the brake pedal, or if the driver does not perform an avoidance maneuver and the automatic brakes are operated, the brake force is generated immediately and the braking distance is reduced.

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Brake control (SCBS brake) operation

Solenoid valve operation table

Hydraulic circuit

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Block diagram

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•  After the brake prefill operates, if the driver does not perform an avoidance maneuver and the laser sensor determines that a collision may occur, it outputs a brake control (SCBS brake) request signal (4) to the DSC HU/CM.

•  The DSC HU/CM energizes the traction control and the stability control solenoid valves to switch the hydraulic circuits and to increase the brake fluid pressure. Therefore the brake is operated automatically (5). At this time, the DSC HU/CM outputs a brake light signal to the body control module (BCM) (6). While the brake control (SCBS brake) is operating, turns on the brake lights automatically (7), and at the same time the brake light unit outputs a brake light operation signal to the DSC HU/CM (8).

•  When the Smart City Brake Support (SCBS) operates and the brakes are applied, the message “SCBS Automatic Brake” is indicated in the active driving display.

•  The brake control (SCBS brake) is kept operated for 2 s. To keep the vehicle stopped after the brake control (SCBS brake) operation ends, the brake pedal has to be depressed to operate the brake.

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Smart City Brake Support [Forward] (SCBS F) display function

•  The instrument cluster displays as indicated in the table below when the vehicle is under the following conditions.

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Smart City Brake Support [Forward] (SCBS F) display function table

Condition		Display content	Smart City Brake Support (SCBS) indicator light (red)	Smart City Brake Support (SCBS) warning light (amber)	Smart City Brake Support (SCBS) OFF indicator light	Active Driving Display*
Smart City Brake Support [Forward] (SCBS F) is off Ignition is switched ON (engine off or on)		Smart City Brake Support [Forward] (SCBS F) system is canceled	Off	Off	On	No display
Smart City Brake Support [Forward] (SCBS F) is on	Danger of collision with vehicle or obstruction ahead	Collision warning operating	Flash	Off	Off
		Brake control (SCBS brake) operating	Flash	Off	Off
	Malfunction occurred in Smart City Brake Support [Forward] (SCBS F) system	Malfunction occurring in Smart City Brake Support [Forward] (SCBS F) system	Off	On	Off	No display

Caution

•  If the DSC system has a malfunction and the DSC control is inhibited, or if the DSC OFF switch is operated and the DSC control is disabled, the Smart City Brake Support (SCBS) does not operate.

•  When the laser sensor malfunction is determined as a result of the on-board diagnostic test, the Smart City Brake Support (SCBS) is suspended while driving.

•  When the DTC is stored in the PCM, DSC HU/CM, and/or instrument cluster, the Smart City Brake Support (SCBS) is suspended depending on the malfunctioning situation.

Note

•  If the Smart Brake Support (SBS) system operation is turned off, the Smart City Brake Support (SCBS) system operation is turned off simultaneously.