REAR CROSS TRAFFIC ALERT (RCTA) SYSTEM

id151000007000


Outline

•  The rear cross traffic alert system detects vehicles approaching from behind using radar and alerts the driver of the presence of an approaching vehicle.
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Structural view

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Function

•  The rear cross traffic alert system detects vehicles approaching from the rear of the detecting vehicle.
•  The rear cross traffic alert system alerts the driver to the presence of an approaching vehicle when the vehicle is reversing.

Rear cross traffic alert system

•  The rear cross traffic alert system operates when the selector lever is in the R position and starts the detection of approaching vehicles. The driver is notified when the rear side radar sensor on the right side detects an approaching vehicle that will enter the warning line shown in the figure within approx. 3.5 s.
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•  When the rear side radar sensor on the right side detects an approaching vehicle, it warns the driver by flashing the blind spot monitoring (BSM) warning indicator light and activating the blind spot monitoring (BSM) warning sound.
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System check

•  When the ignition is switched ON (engine off or on), the system conditions are checked for approx. 3 s. The blind spot monitoring (BSM) warning indicator light is turned on during the system check, and it is turned off when the system check is finished.


System conditions display

•  The rear side radar sensor on the right side displays the system conditions in the instrument cluster and on the center display.

System condition

i-ACTIVSENSE status symbol (warning/risk avoidance support system)

i-ACTIVSENSE OFF symbol (warning/risk avoidance support system)

Blind spot monitoring (BSM) warning indicator light

Blind spot monitoring (BSM) warning sound

Multi-information display

Active driving display

Center display
Right after switch the ignition ON (engine off or on)
(System check)
ON (approx. 3 s)
OFF
ON (approx. 3 s)
OFF
No display
No display
No display
Vehicle is driven in reverse
No approaching vehicle which will reach alert area within 3.5 s
OFF
OFF
OFF
No display
No display
No display
Detects approaching vehicle which will reach alert area from left side within 3.5 s
OFF
Flash
ON
No display
No display
Detects approaching vehicle which will reach alert area from right side within 3.5 s
OFF
Flash
ON
No display
No display
Detects approaching vehicles which will reach alert area from both sides within 3.5 s
OFF
Flash
ON
No display
No display
Rear cross traffic alert system is on (system operational status)
System is OFF (non-operational)
OFF
ON
OFF
OFF
No display
No display
No display
Blind spot monitoring (BSM) system malfunction occurred
OFF
OFF
OFF
No display
Warning display


System wiring diagram

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Operation

Warning
•  The rear cross traffic alert system assists the driver in checking the rear of the vehicle while reversing. Because there are various restrictions in the system operations, the alert may not be performed or may be delayed even if a vehicle is present at the rear of the detecting vehicle, which may result in an accident. Do not rely completely on the system and always take responsibility as the driver in confirming the area behind the vehicle.
Caution
•  The system may operate even if no vehicle is approaching under the following conditions.
―  There is roadside object which reflects radar, such as parked vehicle, guardrail, or wall, by side of detecting vehicle
―  A vehicle approaching from the rear or from the side of the detecting vehicle is decelerating
―  A vehicle approaching from the rear or from the side of the detecting vehicle turns left or right directly in front of the detecting vehicle
―  Vehicles are stopped around the detecting vehicle in heavy traffic
―  Vehicle is near facility which generates strong radio waves or electrical noises such as TV tower or power plant
•  The system turns on the i-ACTIVSENSE warning light and stops operating under the following conditions. If the i-ACTIVSENSE warning light remains on, have the vehicle inspected at an Authorized Mazda Dealer as soon as possible.
―  There is some malfunction with system including blind spot monitoring (BSM) warning indicator lights
―  Large deviation in installation position of rear side radar sensor on vehicle has occurred
―  There is large amount of snow or ice on rear bumper near rear side radar sensor
―  Vehicle is driven on snowy roads for long period
―  Temperature near radar becomes excessively high such as when climbing uphill road for long period on hot day
―  Battery voltage is low
•  The rear side radar sensor may not detect or have difficulty in detecting under the following conditions.
―  Vehicle speed when reversing is approx. 10 km/h or more
―  Detection area of rear side radar sensor is obstructed by adjacent wall or parked vehicle
―  Vehicle approaches from directly behind detecting vehicle
―  Detecting vehicle is parked at an angle
―  Immediately after rear cross traffic alert system is made operable
―  Sensor receives radio interference by radar sensor installed on adjacent vehicle
―  Rear bumper is deformed near rear side radar sensor
―  Approaching vehicle has one or more of following characteristics in shape
1.  Vehicle size is very small
2.  Vehicle height is very low/high
3.  Has complex shape such as of special vehicle
•  The flashing of the blind spot monitoring (BSM) warning indicator lights installed to the outer mirrors may not be clearly visible under the following conditions.
―  Ice or snow is adhering to outer mirrors
―  Fog, snow, dirt, or frost is adhering to windshield
•  When towing a trailer, or if something is installed to the rear part of the vehicle such as a bicycle carrier, cancel the rear cross traffic alert. The system may not operate normally because the radio waves of the radar may be obstructed.

•  When all of the following conditions are met, the rear cross traffic alert system goes on operation standby.
Preconditions
―  Rear cross traffic alert system is on (system operational status)
Note
•  The rear cross traffic alert system can be turned on/off using the personalization features.
―  Rear cross traffic alert system is normal
―  Back-up light on request signal is received
•  The warning is activated if the following condition is met.
Operation conditions
―  Approaching vehicle or pedestrian is detected that will reach alert area within 3.5 s
•  When all of the following conditions are met, the rear cross traffic alert system turns off.
Stop conditions
―  Rear cross traffic alert system is off (system operation stop)
Note
•  The rear cross traffic alert system can be turned on/off using the personalization features.
―  Rear cross traffic alert system malfunction occurring
―  Back-up light on request signal is not received
If a vehicle is approaching on the left side
1.  The rear side radar sensor starts to detect approaching vehicles using the radio waves it is emitting when the preconditions are met.
2.  When the rear side radar sensor on the left side detects an approaching vehicle, it sends target information (1) to the rear side radar sensor on the right side.
3.  When the rear side radar sensor on the right side recognizes the approaching vehicle while reversing, it sends the RCTA signal (2) to the door-electrical supply unit driver, door-electrical supply unit passenger, instrument cluster, active driving display, and connectivity master unit (CMU) via the body control module (BCM).
4.  Based on the RCTA signal (2), the body control module (BCM) outputs the warning sound signal (3) to the notification and warning speaker (rear) to activate the warning sound.
5.  Based on the RCTA signal (2), the instrument cluster displays a warning indication (3) on the multi-information display, and the active driving display displays a warning indication (3) on the windshield, and the connectivity master unit (CMU) displays a warning indication (3) on the center display.
6.  Based on the RCTA signal (2), the door-electrical supply unit driver and the door-electrical supply unit passenger flash the blind spot monitoring (BSM) warning indicator lights (3).
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If a vehicle is approaching on the right side
1.  The rear side radar sensor starts to detect approaching vehicles using the radio waves it is emitting when the preconditions are met.
2.  When the rear side radar sensor on the right side detects the approaching vehicle while reversing, it sends the RCTA signal (1) to the door-electrical supply unit driver, door-electrical supply unit passenger, instrument cluster, active driving display, and connectivity master unit (CMU) via the body control module (BCM).
3.  Based on the RCTA signal (1), the body control module (BCM) outputs the warning sound signal (2) to the notification and warning speaker (rear) to activate the warning sound.
4.  Based on the RCTA signal (1), the instrument cluster displays a warning indication (2) on the multi-information display, and the active driving display displays a warning indication (2) on the windshield, and the connectivity master unit (CMU) displays a warning indication (2) on the center display.
5.  Based on the RCTA signal (1), the door-electrical supply unit driver and the door-electrical supply unit passenger flash the blind spot monitoring (BSM) warning indicator lights (2).
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