MAZDA RADAR CRUISE CONTROL WITH STOP & GO FUNCTION (MRCC WITH STOP & GO FUNCTION)
id151000004000
Outline
• The Mazda Radar Cruise Control with Stop & Go function (MRCC with Stop & Go function) uses the front radar sensor and the forward sensing camera (FSC) to detect a vehicle ahead, and performs headway control to maintain a constant distance from a vehicle ahead without a driver having to depress the accelerator or brake pedal. In addition, the detecting vehicle stops when the vehicle ahead stops, and headway control resumes by operating the RES switch/accelerator pedal after the vehicle ahead moves again. This reduces the strain of operating the vehicle such as during long-distance driving, driving at high speeds, and while in heavy traffic. If the detecting vehicle approaches the vehicle ahead too closely such as when the vehicle ahead is braking suddenly, the system alerts the driver using a warning sound and warning indication.
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Warning
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• Do not rely completely on the Mazda Radar Cruise Control with Stop & Go function (MRCC with Stop & Go function) and always drive carefully. There are limitations to the distance between the vehicles which can be controlled by the Mazda Radar Cruise Control with Stop & Go function (MRCC with Stop & Go function), and if the accelerator pedal or brake pedal is mistakenly operated it could result in an accident. Always keep a safe distance from the vehicle ahead by depressing the brake pedal if necessary while verifying the safety of the surrounding area.
• The Mazda Radar Cruise Control with Stop & Go function (MRCC with Stop & Go function) performs brake control, however, there are limitations to the deceleration, 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 keep a safe distance from the vehicle ahead by depressing the brake pedal if necessary while verifying the safety of the surrounding area.
Structural view
Function
• The Mazda Radar Cruise Control with Stop & Go function (MRCC with Stop & Go function) has the following modes.
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― Continuous constant speed control mode: Drives the vehicle at the set vehicle speed set by the driver based on the cruise control switch operation signal.
― Constant speed control mode: Drives the vehicle at the set vehicle speed set by the driver based on the cruise control switch operation signal. In addition, the system switches to headway control mode when a vehicle ahead is detected.
― Headway control mode: When a vehicle ahead is detected while the vehicle is traveling in constant speed control mode, headway control with the vehicle ahead is performed while maintaining the set distance between the vehicles using the distance between vehicles setting function. In addition, the detecting vehicle stops when the vehicle ahead stops, and headway control mode/constant speed control mode resumes by operating the RES switch/accelerator pedal after the vehicle ahead moves again.
Mode switching function
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• The Mazda Radar Cruise Control with Stop & Go function (MRCC with Stop & Go function) can be switched as follows.
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Note
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• When switching from constant speed control mode/headway control mode to continuous constant speed control mode, the set vehicle speed must be reset.
Distance between vehicles setting function
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• Using the DISTANCE switch on the cruise control switch, the distance between vehicles during headway control mode can be controlled at 4 levels, including longÆmediumÆshortÆextremely short. (Initial setting is LONG)
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Caution
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• The distances between vehicles indicated below are average values during travel on flat roads and differ depending on the driving and road conditions.
Distance between vehicles table (reference)
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Set distance between vehicles
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Monitoring vehicle speed
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0 km/h
{0 mph}
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10 km/h
{6.2 mph}
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20 km/h
{12 mph}
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30 km/h
{19 mph}
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40 km/h
{25 mph}
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50 km/h
{31 mph}
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60 km/h
{37 mph}
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Long
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5 m
{17 ft}
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11 m
{37 ft}
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18 m
(60 ft)
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24 m
{79 ft}
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30 m
{99 ft}
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37 m
{122 ft}
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43 m
{142 ft}
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Medium
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5 m
{17 ft}
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10 m
{33 ft}
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15 m
{50 ft}
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20 m
{66 ft}
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26 m
{86 ft}
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31 m
{102 ft}
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36 m
{119 ft}
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Short
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5 m
{17 ft}
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10 m
{33 ft}
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15 m
{50 ft}
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18 m
{60 ft}
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22 m
{73 ft}
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25 m
{83 ft}
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29 m
{96 ft}
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Extremely short
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5 m
{17 ft}
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10 m
{33 ft}
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15 m
{50 ft}
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17 m
{56 ft}
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19 m
{63 ft}
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22 m
{73 ft}
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24 m
{79 ft}
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Set distance between vehicles
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Monitoring vehicle speed
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70 km/h
{43 mph}
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80 km/h
{50 mph}
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90 km/h
{56 mph}
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100 km/h
{62 mph}
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110 km/h
{68 mph}
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120 km/h
{75 mph}
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130 km/h
{81 mph}
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140 km/h
{87 mph}
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Long
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49 m
{161 ft}
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56 m
{184 ft}
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62 m
{204 ft}
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68 m
{224 ft}
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75 m
{247 ft}
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81 m
{266 ft}
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87 m
{286 ft}
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94 m
{309 ft}
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Medium
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41 m
{135 ft}
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46 m
{150 ft}
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51 m
{168 ft}
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56 m
{184 ft}
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62 m
{204 ft}
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67 m
{220 ft}
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72 m
{237 ft}
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77 m
{253 ft}
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Short
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32 m
{105 ft}
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35 m
{115 ft}
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39 m
{128 ft}
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42 m
{138 ft}
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46 m
{151 ft}
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49 m
{161 ft}
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52 m
{171 ft}
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56 m
{184 ft}
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Extremely short
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26 m
{86 ft}
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28 m
{92 ft}
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31 m
{102 ft}
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33 m
{109 ft}
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35 m
{115 ft}
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37 m
{122 ft}
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39 m
{128 ft}
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42 m
{138 ft}
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System conditions display
• The body control module (BCM) displays the system status using the Mazda radar cruise control (MRCC) warning indication, Mazda radar cruise control (MRCC) standby indication, Mazda radar cruise control (MRCC) set indication, active driving display, multi-information display, and the center display.
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Condition
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MRCC standby indication
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MRCC set indication
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i-ACTIVSENSE warning indication
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Multi-information display indication (Instrument cluster)
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Active driving display indication
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MRCC system is OFF
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Off
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Off
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Off
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No display
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No display
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MRCC system is ON
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MRCC system is on standby
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On
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Off
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Off
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Vehicle speed is set
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Off
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On
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Off
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Vehicle ahead is detected
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Off
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On
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Off
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Distance between vehicles
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Long
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Off
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On
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Off
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Medium
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Off
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On
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Off
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Short
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Off
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On
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Off
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Extremely short
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Off
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On
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Off
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MRCC system is ON
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Accelerator pedal is depressed
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On
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Off
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Off
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No display
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During stop hold control
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*1
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*1
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Off
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Vehicle ahead accelerated forward during stop hold control
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*1
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*1
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Off
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No display
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Shift up/down required
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Off
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Off
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Off
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Deceleration exceeding system limits required
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Off
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On
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Off
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No display
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MRCC system is automatically canceled due to low vehicle speed
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Off
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Off
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Off
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Dirty front radar sensor is detected
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Off
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Off
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On
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No display
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MRCC cannot operate at 30 km/h {20 mph} or less
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*1
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*1
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On
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No display
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Malfunction occurred in MRCC system
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Off
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Off
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On
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No display
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MRCC no longer operates
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Off
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Off
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On
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No display
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*1 :The on/off differs depending on the control condition.
System wiring diagram
Block diagram
Operation
• For details on autohold, refer to [AUTOHOLD]. (See
AUTOHOLD.)
• When all of the following conditions are met, the Mazda Radar Cruise Control with Stop & Go function (MRCC with Stop & Go function) goes on operation stand-by.
Operation conditions
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― Selector lever is in D position
― Vehicle speed is within range of approx. 0—200 km/h {0—124.0 mph}
― Mazda Radar Cruise Control with Stop & Go function (MRCC with Stop & Go function) is turned on
― Brake pedal is not depressed
― DSC is not operating
― Smart brake support (SBS) is not operating
― The Electric Parking Brake (EPB) is released (Electric Parking Brake (EPB) indicator light is turned off)
― Driver seat belt is fastened
― All doors are closed
Constant speed control mode
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1. The body control module (BCM) recognizes the vehicle speed set by the driver based on the cruise control switch operation signal (1) sent from the instrument cluster when the operation conditions are met.
2. The body control module (BCM) sends the set vehicle speed signal (2) and system status indication request signal (2) to the instrument cluster and the active driving display based on the recognized set vehicle speed.
3. The body control module (BCM) sends the target acceleration speed signal (3) to the PCM based on the recognized set vehicle speed.
4. The PCM performs drive force control based on the target acceleration speed signal (3) from the body control module (BCM). If the PCM determines that the target acceleration speed cannot be achieved by drive force control only, it sends a target acceleration speed signal (4) to the electronically controlled brake unit.
5. The electronically controlled brake unit performs brake control based on the target acceleration speed signal (4) from the PCM.
6. The system operation screen is displayed by the instrument cluster and the active driving display based on the set vehicle speed signal (2) and the system status indication request signal (2) from the body control module (BCM).
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Note
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• When the front radar sensor and forward sensing camera (FSC) detect a vehicle ahead, constant speed control mode transitions to headway control mode.
Headway control mode
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1. When the front radar sensor and the forward sensing camera (FSC) detect target information while driving in constant speed control mode, they send target information to the body control module (BCM) and switch to headway control mode.
2. The body control module (BCM) calculates (1) the target acceleration speed based on the following and sends (2) a target acceleration speed signal to the PCM.
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― Distance between vehicles set by driver
― Target information (position of vehicle ahead, distance between vehicles, relative vehicle speed)
― Detecting vehicle speed
3. The PCM performs drive force control based on the target acceleration speed signal (2) from the body control module (BCM). If the PCM determines that the target acceleration speed cannot be achieved by drive force control only, it sends a target acceleration speed signal (3) to the electronically controlled brake unit.
4. The electronically controlled brake unit performs brake control based on the target acceleration speed signal (3) from the PCM.
5. The instrument cluster displays the vehicle ahead screen on the multi-information display based on the system status indication signal from the body control module (BCM).
6. The active driving display displays the vehicle ahead screen based on the system status indication request signal (2) from the body control module (BCM).
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Note
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• In the following cases, the system transitions from headway control mode to constant speed mode.
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― Vehicle ahead accelerates over set vehicle speed of detecting vehicle
― Vehicle ahead or detecting vehicle switches driving lanes, and vehicle ahead of detecting vehicle no longer exists
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Stop hold control
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1. If the vehicle ahead stops during headway control mode, the front radar sensor and the forward sensing camera (FSC) send target information to the body control module (BCM), and the body control module (BCM) sends a system control signal to the PCM and the electronically controlled brake unit to stop the vehicle at the previously set distance between vehicles.
2. The PCM controls the drive force and stops the vehicle based on the system control signal from the body control module (BCM).
3. The electronically controlled brake unit performs brake control to stop the vehicle and maintain it in a stopped condition based on the system control signal from the body control module (BCM).
4. The body control module (BCM) sends an AUTOHOLD operation indicator light request signal to the instrument cluster after the vehicle stops.
5. The instrument cluster turns on the AUTOHOLD operation indicator light based on the AUTOHOLD operation indicator light request signal from the body control module (BCM).
6. After the body control module (BCM) recognizes that the vehicle ahead has accelerated forward during stop hold control, the PCM and the electronically controlled brake unit cancel stop hold control when they receive the following signals.
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― Accelerator pedal opening angle signal (accelerator pedal depressed) from PCM
― RES switch ON signal (RES switch pressed) from instrument cluster
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Note
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• After the vehicle ahead accelerates forward and a certain period of time has elapsed, the vehicle ahead indication on the multi-information display flashes to promote the driver to accelerate the vehicle.
• The electrical supply unit (ESU) turns on the brake lights during stop hold control.
• When 10 min or more have elapsed since stop hold control was operated, the electric parking brake operates and the Mazda Radar Cruise Control with Stop & Go function (MRCC with Stop & Go function) goes on stand-by.
7. The body control module (BCM) sends a system control signal to the PCM and the electronically controlled brake unit to resume headway control mode/constant speed control mode.
Inter-vehicle distance limit warning
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• If the following condition is met, the warning alarm in the instrument cluster is activated and the brake warning on the display is indicated to urge the driver to take action such as braking.
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― Body control module (BCM) determines that collision with vehicle ahead is unavoidable even if collision reduction braking at maximum possible deceleration speed is performed
