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 a radar unit to detect a vehicle ahead, and performs headway control to maintain a constant distance from a vehicle ahead without the 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 for the Mazda Radar Cruise Control with Stop & Go function (MRCC with Stop & Go function) to control the distance between the vehicles, 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 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.
Functions
• 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 vehicle speed set by the driver and a constant distance between the vehicles. 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 long→medium→short→extremely 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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Detecting 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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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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Long
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4 m
{13 ft}
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10 m
{32 ft}
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17 m
{56 ft}
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23 m
{75 ft}
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29 m
{95 ft}
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36 m
{118 ft}
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42 m
{138 ft}
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48 m
{157 ft}
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55 m
{180 ft}
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61 m
{200 ft}
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67 m
{220 ft}
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74 m
{243 ft}
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Medium
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4 m
{13 ft}
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10 m
{32 ft}
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15 m
{49 ft}
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19 m
{62 ft}
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24 m
{79 ft}
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29 m
{95 ft}
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34 m
{112 ft}
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39 m
{128 ft}
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44 m
{144 ft}
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49 m
{161 ft}
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53 m
{174 ft}
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58 m
{190 ft}
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Short
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4 m
{13 ft}
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10 m
{32 ft}
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13 m
{43 ft}
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16 m
{52 ft}
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19 m
{62 ft}
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22 m
{72 ft}
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25 m
{82 ft}
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29 m
{95 ft}
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32 m
{105 ft}
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36 m
{118 ft}
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40 m
{131 ft}
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43 m
{141 ft}
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Extremely short
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4 m
{13 ft}
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10 m
{32 ft}
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12 m
{39 ft}
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13 m
{43 ft}
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15 m
{49 ft}
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17 m
{56 ft}
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20 m
{66 ft}
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22 m
{72 ft}
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25 m
{82 ft}
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27 m
{89 ft}
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30 m
{98 ft}
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32 m
{105 ft}
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Set distance between vehicles
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Detecting vehicle speed
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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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80 m
{262 ft}
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86 m
{282 ft}
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93 m
{305 ft}
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Medium
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63 m
{207 ft}
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68 m
{223 ft}
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73 m
{240 ft}
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Short
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47 m
{154 ft}
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50 m
{164 ft}
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54 m
{177 ft}
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Extremely short
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35 m
{115 ft}
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38 m
{125 ft}
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40 m
{131 ft}
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System conditions display function
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• The radar unit displays the system status using the Mazda radar cruise control (MRCC) warning indication/Mazda radar cruise control (MRCC) main indication/Mazda radar cruise control (MRCC) set indication, active driving display, multi-information display, and center display.
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Condition
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MRCC main indication
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MRCC set indication
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MRCC warning indication
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*1
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Multi-information display indication
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Active driving display indication
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Center display
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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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OFF
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No display
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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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OFF
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No display
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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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OFF
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No display
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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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OFF
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No display
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Distance between vehicles is set
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Long
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OFF
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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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Medium
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OFF
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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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Short
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OFF
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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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Extremely short
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OFF
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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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MRCC system is ON
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Accelerator pedal is depressed
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OFF
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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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OFF
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ON
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OFF
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ON
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No display
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Deceleration exceeding system limits is required
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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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MRCC system is automatically canceled due to low vehicle speed
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ON
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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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Dirty radar unit is detected
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OFF
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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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Warning display*2
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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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OFF
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No display
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Warning display*2
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*1 :Mazda Radar Cruise Control with Stop & Go function (MRCC with Stop & Go function) indicator light
*2 :For the warning display content on the center display, refer to the [CENTER DISPLAY]. (See
CENTER DISPLAY.)
Structural View
System Wiring Diagram
Block Diagram
Block diagram (MRCC/SBS/DRSS)
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 condition
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― Selector lever is in D or M position
― Vehicle speed is within range of approx. 0—145 km/h {0—90 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 city brake support (SCBS) is not operating
― Smart brake support (SBS) is not operating
― Electric parking brake is released
― Driver seat belt is fastened
― All doors are closed
Constant speed control mode
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1. The PCM recognizes the set vehicle speed set by the driver based on the cruise control switch operation signal sent from the start stop unit when the operation conditions are met.
2. When the PCM recognizes the set vehicle speed, it sends a set vehicle speed signal and system condition signal to the radar unit, instrument cluster, and active driving display.
3. The radar unit sends a target acceleration speed signal to the PCM based on the set vehicle speed signal and system condition signal.
4. The PCM performs engine control to maintain the set vehicle speed based on the signal from the radar unit.
5. The instrument cluster and active driving display display the system operation screen based on the set vehicle speed signal and system condition signal from the PCM.
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Note
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• When the radar unit detects the target information while in constant speed control mode, it switches the mode to headway control mode.
Headway control mode
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1. When the radar unit detects the target information while the vehicle is traveling in constant speed control mode, it switches the mode to headway control mode.
2. The radar unit calculates the target acceleration speed based on the following, and sends the target acceleration speed signal to the PCM and DSC HU/CM. Additionally, it sends the system status display request signal to the instrument cluster.
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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 engine control to maintain distance between vehicles based on the signal from the radar unit.
4. The DSC HU/CM controls braking to maintain distance between vehicles based on the signal from the radar unit.
5. The instrument cluster displays the vehicle ahead screen based on the signal from the radar unit.
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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 radar unit sends a system control signal to the PCM and DSC HU/CM so that the vehicle stops at the previously set distance-between-vehicles.
2. The PCM performs engine control and stops the vehicle based on the system control signal from the radar unit.
3. The DSC HU/CM performs brake control, stops the vehicle, and maintains a stopped condition based on the system control signal from the radar unit.
4. The radar unit sends the stop hold control status indication request signal to the instrument cluster after the vehicle was stopped.
5. The instrument cluster displays the stop hold control indication in the multi-information display and turns the Mazda Radar Cruise Control with Stop & Go function (MRCC with Stop & Go function) indicator light on based on the stop hold control status indication request signal from the radar unit.
6. After the radar unit recognizes that the vehicle ahead has accelerated forward during stop hold control, the PCM and DSC HU/CM cancels stop hold control when it receives the following signals.
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― Accelerator pedal opening angle signal (accelerator pedal depressed) from PCM
― RESUME switch ON signal (RESUME switch pressed) from start stop unit
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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 in the multi-information display flashes to promote the driver to accelerate the vehicle.
• When 10 min or more have elapsed since stop hold control was operated, the electric parking brake automatically operates and the Mazda Radar Cruise Control with Stop & Go function (MRCC with Stop & Go function) goes on stand-by.
7. The radar unit sends the system control signal to the PCM and DSC HU/CM and resumes headway control mode/constant speed control mode.
Inter-vehicle distance limit warning
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• If any of the following condition is met, the warning alarm in the instrument cluster is activated and the brake warning in the display is indicated to urge the driver to take action such as braking.
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― Radar unit determines that crash is unavoidable even if automatic braking is performed at maximum possible deceleration rate such as vehicle ahead performs emergency braking
