MAZDA RADAR CRUISE CONTROL WITH STOP & GO FUNCTION (MRCC WITH STOP & GO FUNCTION)

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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. Additionally, if the vehicle ahead stops during headway control, the vehicle automatically stops and maintains a stopped condition. If the 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.
Warning
•  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.
•  Brake control is performed, 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.

Functions

•  The mazda radar cruise control with stop & go function (MRCC with stop & go function) is equipped with the following indicated modes.
―  Constant speed control mode: Drives the vehicle at the set vehicle speed set by the driver based on the cruise control switch operation signal.
―  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.

Mode switching function

•  The modes in the mazda radar cruise control with stop & go function (MRCC with stop & go function) can be switched as follows.
Note
•  When switching from constant speed control mode/headway control mode to normal constant speed control mode, the set vehicle speed must be reset. In addition, when switching from normal constant speed control mode to constant speed control mode/headway control mode, the vehicle speed becomes the speed set before switching from normal constant speed control mode.
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Distance between vehicles setting function

•  Using the DISTANCE switch on the cruise control switch, the distance between vehicles can be controlled at 4 levels, including long→medium→short→extremely short. (Initial setting is set to LONG)
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Caution
•  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)

VIN serial No. 100001—

Set distance between vehicles

Detecting vehicle speed

0 km/h {0 mph}

10 km/h {6.2 mph}

20 km/h {12 mph}

30 km/h {19 mph}

40 km/h {25 mph}

50 km/h {31 mph}
Long
4 m
{13 ft}
10.5 m
{34 ft}
17 m
{55 ft}
23 m
{75 ft}
29 m
{95 ft}
36 m
{118 ft}
Medium
4 m
{13 ft}
10 m
{32 ft}
15 m
{49 ft}
19 m
{62 ft}
24 m
{79 ft}
29 m
{95 ft}
Short
4 m
{13 ft}
9.5 m
{31 ft}
13 m
{42 ft}
17 m
{55 ft}
21 m
{68 ft}
24 m
{78 ft}
Extremely short
4 m
{13 ft}
9 m
{29 ft}
12 m
{39 ft}
16 m
{52 ft}
18 m
{59 ft}
21 m
{68 ft}

Set distance between vehicles

Detecting vehicle speed

60 km/h {37 mph}

70 km/h {43 mph}

80 km/h {50 mph}

90 km/h {56 mph}

100 km/h {62 mph}

110 km/h {68 mph}
Long
42 m
{138 ft}
48 m
{157 ft}
55 m
{180 ft}
61 m
{200 ft}
67 m
{220 ft}
74 m
{243 ft}
Medium
34 m
{112 ft}
39 m
{128 ft}
44 m
{144 ft}
49 m
{161 ft}
53 m
{174 ft}
58 m
{190 ft}
Short
26 m
{85 ft}
29 m
{95 ft}
32 m
{105 ft}
36 m
{118 ft}
40 m
{131 ft}
43 m
{141 ft}
Extremely short
22 m
{72 ft}
23 m
{75 ft}
25 m
{82 ft}
27 m
{89 ft}
30 m
{98 ft}
32 m
{105 ft}

Set distance between vehicles

Detecting vehicle speed

120 km/h {75 mph}

130 km/h {81 mph}

140 km/h {87 mph}
Long
80 m
{262 ft}
86 m
{282 ft}
93 m
{305 ft}
Medium
63 m
{207 ft}
68 m
{223 ft}
73 m
{240 ft}
Short
47 m
{154 ft}
50 m
{164 ft}
54 m
{177 ft}
Extremely short
35 m
{115 ft}
38 m
{125 ft}
40 m
{131 ft}

VIN serial No. 200001—

Set distance between vehicles

Detecting vehicle speed

0 km/h {0 mph}

10 km/h {6.2 mph}

20 km/h {12 mph}

30 km/h {19 mph}

40 km/h {25 mph}

50 km/h {31 mph}
Long
4 m
{13 ft}
10 m
{32 ft}
17 m
{55 ft}
23 m
{75 ft}
29 m
{95 ft}
36 m
{118 ft}
Medium
4 m
{13 ft}
10 m
{32 ft}
15 m
{49 ft}
19 m
{62 ft}
24 m
{79 ft}
29 m
{95 ft}
Short
4 m
{13 ft}
10 m
{32 ft}
13 m
{42 ft}
16 m
{52 ft}
19 m
{62 ft}
22 m
{72 ft}
Extremely short
4 m
{13 ft}
10 m
{32 ft}
12 m
{39 ft}
13 m
{43 ft}
15 m
{49 ft}
17 m
{56 ft}

Set distance between vehicles

Detecting vehicle speed

60 km/h {37 mph}

70 km/h {43 mph}

80 km/h {50 mph}

90 km/h {56 mph}

100 km/h {62 mph}

110 km/h {68 mph}
Long
42 m
{138 ft}
48 m
{157 ft}
55 m
{180 ft}
61 m
{200 ft}
67 m
{220 ft}
74 m
{243 ft}
Medium
25 m
{82 ft}
29 m
{95 ft}
44 m
{144 ft}
49 m
{161 ft}
53 m
{174 ft}
58 m
{190 ft}
Short
20 m
{66 ft}
22 m
{72 ft}
32 m
{105 ft}
36 m
{118 ft}
40 m
{131 ft}
43 m
{141 ft}
Extremely short
22 m
{72 ft}
23 m
{75 ft}
25 m
{82 ft}
27 m
{89 ft}
30 m
{98 ft}
32 m
{105 ft}

Set distance between vehicles

Detecting vehicle speed

120 km/h {75 mph}

130 km/h {81 mph}

140 km/h {87 mph}
Long
80 m
{262 ft}
86 m
{282 ft}
93 m
{305 ft}
Medium
63 m
{207 ft}
68 m
{223 ft}
73 m
{240 ft}
Short
47 m
{154 ft}
50 m
{164 ft}
54 m
{177 ft}
Extremely short
35 m
{115 ft}
38 m
{125 ft}
40 m
{131 ft}


System conditions display function

•  The radar unit displays the system status using the MRCC indicator light (green)/warning light (amber), active driving display/multi-information display, and center display.

Condition

MRCC main indication

MRCC set indication

MRCC warning indication

*1

Multi-information display indication

Active driving display indication

Center display
System is OFF
Off
Off
Off
Off
No display
No display
No display
System is ON
System is on standby
On
Off
Off
Off
No display
No display
Vehicle speed is set
Off
On
Off
Off
No display
System is ON
Vehicle ahead is detected
Off
On
Off
Off
No display
Distance between vehicles
Long
Off
On
Off
Off
No display
Medium
Off
On
Off
Off
No display
Short
Off
On
Off
Off
No display
Extremely short
Off
On
Off
Off
No display
Accelerator pedal is depressed
Off
On
Off
Off
No display
During stop hold control
Off
On
Off
On
No display
System is ON
Accelerator pedal is depressed
Off
On
Off
Off
No display
Switching from constant speed control mode/headway control mode to normal constant speed control mode
Off
Off
Off
Off
No display
No display
Deceleration exceeding system limits required
Off
Off
Off
Off
No display
•  Electric parking brake is malfunctioning
•  Stop hold control is malfunctioning
•  Laser sensor is not operating normally
Off
On
Off
Off
No display
No display
MRCC system is automatically canceled due to low vehicle speed
On
Off
Off
Off
No display
Dirty radar unit is detected
Off
Off
On
Off
No display
Warning display*2
Malfunction occurred in system
Off
Off
On
Off
No display
Warning display*2

*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

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System Wiring Diagram

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Block Diagram

Block diagram (MRCC/SBS/DRSS)

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Operation

•  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 standby.
Operation condition
―  Selector lever is in D or M position
―  Vehicle speed is within range of 0—145 km/h {0 mph—90.0 mph}
―  Mazda radar cruise control with stop & go function (MRCC with stop & go function) is ON
―  Brake pedal is not depressed
―  DSC is not operating
―  TCS is not operating
―  Smart city brake support (SCBS) is not operating
―  Smart brake support (SBS) is not operating
―  Electric parking brake is released
―  No malfunction in DSC system (No DTCs stored in memory)
―  No malfunction in mazda radar cruise control with stop & go function (MRCC with stop & go function) (No DTCs stored in memory)
―  Driver seat belt is fastened
―  All doors and liftgate are closed

Constant speed control mode

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 sent vehicle speed signal and system condition signal from the PCM.
Note
•  When the radar unit detects the target information while in constant speed control mode, it switches the mode to headway control mode.
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Headway control mode

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 conditions indication request signal to the instrument cluster and the active driving display.
―  Distance between vehicles set by driver
―  Target information
―  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 and the active driving display display the vehicle ahead screen based on the signal from the radar unit.
Note
•  In the following cases, the system transitions from headway control mode to constant speed mode.
―  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
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 when approx. 3 s have elapsed since 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, it sends the stop hold control cancel signal to the PCM and DSC HU/CM when the radar unit receives any of the following signals.
―  Accelerator pedal opening angle signal (accelerator pedal depressed) from PCM
―  RESUME switch ON signal (RESUME switch pressed) from start stop unit
Note
•  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 PCM and DSC HU/CM cancels the stop hold control based on the stop hold control cancel signal from the radar unit and accelerates the vehicle forward.
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Inter-vehicle distance limit warning

•  If any of the following conditions 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
―  Vehicle ahead performs emergency braking