SMART CITY BRAKE SUPPORT [FORWARD] (SCBS F)

id151000003200

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 [Forward] (SCBS F) 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 [Forward] (SCBS F) system not operating normally.

Note

•  The Smart City Brake Support [Forward] (SCBS F) system is designed to assist the driver. The driver's driving operation always takes priority even while the Smart City Brake Support [Forward] (SCBS F) 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 [Forward] (SCBS F) system operation is canceled.

•  To prevent a mistaken operation of the Smart City Brake Support [Forward] (SCBS F) system when performing a vehicle inspection on a chassis dynamometer, turn off the Smart City Brake Support [Forward] (SCBS F) system using the center display.

Functions

Brake prefill/brake control (SCBS brake)

•  When the laser sensor detects that the vehicle is approaching a vehicle or obstruction ahead, a brake fluid request signal is output to the DSC HU/CM to implement the brake prefill. After this, if the system detects that the driver is not performing evasive maneuvering and there is the danger of a collision, a brake control (SCBS brake) request signal is output to the DSC HU/CM, and brake control (SCBS brake) is activated.

―  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 [Forward] (SCBS F)).

•  Vehicle with multi-information display: Warning indications in the multi-information display and at the same time, the DSC HU/CM activates the brake control by applying the brakes on all four wheels automatically.

•  Vehicle without multi-information display: The Smart City Brake Support (SCBS) indicator light (red) turns on 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 [Forward] (SCBS F) 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 [Forward] (SCBS F) system to operate incorrectly, which could result in an accident.

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

•  Vehicle with multi-information display: The Smart City Brake Support [Forward] (SCBS F) notifies the driver of the system status using the Smart City Brake Support (SCBS) OFF indicator light and the multi-information display.

•  Vehicle without multi-information display: The Smart City Brake Support [Forward] (SCBS F) notifies the driver of the system status using the Smart City Brake Support (SCBS) OFF indicator light and the Smart City Brake Support (SCBS) indicator light (red)/Smart City Brake Support (SCBS) warning light (amber).

Note

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

Construction/Operation

•  The laser sensor is located at the top of the windshield and it detects vehicles and obstructions ahead up to 6 m {236 in} from the vehicle front.

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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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―  While engine is running

―  Vehicle speed is approx. 4 km/h {2 mph} or more and approx. 30 km/h {19 mph} or less

―  No malfunction occurring in the Smart City Brake Support [Forward] (SCBS F) system

―  Smart City Brake Support [Forward] (SCBS F) has not been disabled using personalization feature

―  No malfunction occurring in DSC system

―  Evasive maneuvering (steering, accelerator pedal, or brake pedal operation) is not performed even though distance to vehicle or obstruction ahead is specified value or less

Note

•  The Smart City Brake Support [Forward] (SCBS F) system irradiates target objects with a near-infrared laser and it detects vehicles and obstructions ahead by measuring the waves reflected off them. Therefore, in the following cases, the Smart City Brake Support [Forward] (SCBS F) may not operate normally.

―  Low wave reflection due to shape of vehicle ahead

―  Vehicle ahead is exceptionally dirty

―  Exceptionally poor weather conditions such as rainfall, dense fog, or snowfall.

―  Windshield wipers are not used even though windshield is wet from front washer use or rainfall

―  Windshield is dirty

―  Steering wheel is fully turned to left or right, or vehicle or obstruction ahead is approached while accelerator pedal is depressed

―  Vehicle ahead is truck with low platform, or vehicle with extremely low or high profile

―  Vehicle ahead has special shape such as that of car carrier.

•  Under the following conditions, the Smart City Brake Support [Forward] (SCBS F) may not operate normally.

―  Heavy cargo is loaded in trunk compartment or on rear seat

―  Vehicle ahead or obstruction ahead is significantly offset from center of detecting vehicle

―  While entering/exiting curves, or driving on long or sharp curves, vehicle ahead deviates from center of detecting vehicle

―  Long object such as roof rails are installed to detecting vehicle which cover near-infrared irradiation area of laser sensor

―  Exceptionally high amount of exhaust (black soot) from vehicle ahead or surrounding vehicles, or vehicle ahead/surrounding vehicles throw up water, snow, dust into air

•  The laser sensor may regard the following vehicles or objects as a vehicle ahead or an obstruction, and the Smart City Brake Support [Forward] (SCBS F) system may be activated.

―  Objects close to entrance of curve

―  On-coming vehicle appears while vehicle is cornering to left

―  Narrow railing on bridge, narrow gate or entrance

―  Speed restriction bumps, projections, and reflective metallic objects set up on road

―  Vehicle or obstruction approaches detecting vehicle suddenly

―  Toll gate on toll road

―  Curtain or flag-shaped plastic objects

―  Two-wheeled vehicle traveling on road shoulder

―  Plastic objects such as pylons

―  Pedestrians, animals and trees.

•  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:

―  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.

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 or obstruction ahead, it outputs a brake prefill request signal (1) to the DSC HU/CM.

•  When the DSC HU/CM receives the brake prefill request signal, it activates (2) the pump motor. At this time, all of the solenoid valves are off and the brake fluid pressure generated by the pump motor is conducted (3) 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 recognizes a vehicle or obstruction ahead and depresses the brake pedal, or the driver does not perform evasive maneuvering and the brake control (SCBS brake) is activated, immediate brake force is produced to shorten the braking distance.

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Brake control (SCBS brake) operation

Solenoid valve operation table

Hydraulic circuit diagram

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Block Diagram

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•  If the driver does not perform evasive maneuvering after the brake prefill operation and the laser sensor determines that there is the danger of a collision, a brake control (SCBS brake) request signal (1) is output from the laser sensor to the DSC HU/CM.

•  When the DSC HU/CM receives the brake control (SCBS brake) request signal, it energizes the linear control solenoid valves to switch the hydraulic pressure circuit and increase the brake fluid pressure. As a result, the brake control (SCBS brake) is activated (2).

•  While the brake control (SCBS brake) is operating, a brake light signal (3) from the DSC HU/CM is output to the rear body control module (RBCM) at the same time. The rear body control module (RBCM) which received the signal turns on the brake light signal relay^*1 or it sends the signal to the brake light unit^*2 and turns on the brake lights (4).

•  An answer signal (5) is output to the DSC HU/CM from the brake light relay^*1 or the brake light unit^*2 at the same time the brake lights are illuminated.

•  Vehicle with multi-information display: While the brake control (SCBS brake) is operating, a message is displayed in the multi-information display.

•  Vehicle without multi-information display: While the brake control (SCBS brake) is operating, the Smart City Brake Support (SCBS) indicator light (red) is illuminated.

•  The brake control (SCBS brake) is maintained in this condition for approx. 2 s after the vehicle is stopped. Thereafter, the driver needs to depress the brake pedal to maintain the vehicle in a stopped condition.

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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.

Caution

•  If a DTC is stored by the on-board diagnostic function, the Smart City Brake Support [Forward] (SCBS F) is inhibited.

•  If DTCs are stored in the DSC HU/CM, PCM or instrument cluster, the Smart City Brake Support [Forward] (SCBS F) is inhibited depending on the cause of the malfunction.

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

Condition		Display content	Multi-information display indication (if equipped)	Smart City Brake Support (SCBS) indicator light (red) (if equipped)	Smart City Brake Support (SCBS) warning light (amber) (if equipped)	Smart City Brake Support (SCBS) OFF indicator light
Smart City Brake Support [Forward] (SCBS F) OFF Ignition is switched ON (engine off or on)		Smart City Brake Support [Forward] (SCBS F) is turned OFF	No display	Off	Off	On
Smart City Brake Support [Forward] (SCBS F) ON	Possibility of collision with vehicle or obstruction at rear	Brake control (SCBS brake) operating		On	Off	Off
	If Smart City Brake Support [Forward] (SCBS F) system malfunction occurs	While malfunction occurs in Smart City Brake Support [Forward] (SCBS F) system		Off	On	Off