DYNAMIC RADAR CRUISE CONTROL SYSTEM


  1. FUNCTION OF MAIN COMPONENTS


    1. The main components in the dynamic radar cruise control system have the following functions:

      Component Function
      Millimeter Wave Radar Sensor Assembly

      • Radiates millimeter radar waves forward, uses the reflected waves to detect the presence of a vehicle traveling ahead, the vehicle-to-vehicle distance, and the relative speed.

      • While the system is in vehicle-to-vehicle distance control mode, the millimeter wave radar sensor assembly detects the vehicle ahead based on signals from the built-in millimeter wave radar sensor and forward recognition camera. Then, the millimeter wave radar sensor assembly calculates the acceleration or deceleration rate required in order to attain the target vehicle-to-vehicle distance, and outputs a request signal to the ECM.

      • If the detects a malfunction in the dynamic radar cruise control system, it will store Diagnostic Trouble Codes (DTCs).
      Forward Recognition Camera Detects lane markers and objects on the road ahead using the image captured by the monocular camera and sends the information to the millimeter wave radar sensor assembly.
      Camera Heater (Forward Recognition Hood) The camera heater is heated according to signals from the forward recognition camera.
      Steering Pad Switch Assembly Cruise Control Switch

      • Turns the cruise control system on and off.

      • Vehicle-to-vehicle distance control mode becomes be activated immediately after the main switch is turned on. The mode shifts to constant speed control mode by pressing and holding the switch more than 1.5 sec.
      CANCEL Switch A cancel signal is output to the ECM when this switch is operated.
      +RES Switch The acceleration function and resuming of a preset speed can be performed by operating this switch. A signal is output to the ECM when this switch is operated.
      -SET Switch The deceleration function and vehicle speed setting resume signals are output to the ECM when this switch is operated.
      Vehicle-to-vehicle Distance Control Switch While the system is in vehicle-to-vehicle distance control mode, the driver can operate the vehicle-to-vehicle distance control switch to select the vehicle-to-vehicle distance in three levels: long, middle and short.
      Combination Meter Assembly Cruise Control Indicator

      • Based on a cruise control indicator operation signal sent by the ECM, the combination meter assembly illuminates the cruise control indicator (constant speed control mode) or cruise control indicator (vehicle-to-vehicle distance control mode) when the cruise control system has been turned on using the cruise control switch on the steering pad switch assembly.

      • Based on a cruise control indicator operation signal sent by the ECM, the combination meter assembly turns off the cruise control indicator if a malfunction occurs in the cruise control system.
      Cruise SET Indicator Cruise SET indicator Illuminates when the vehicle speed is set.
      Multi-information Display

      • Displays a warning message to alert the driver in accordance with a signal provided by the ECM.

      • During dynamic radar cruise control operation, the multi-information display receives signals from the ECM in order to display the system conditions.
      Buzzer

      • Sounds a buzzer when it receives a signal from the ECM to alert the driver that the distance between vehicles is short.

      • If the ECM detects automatic cancel or warning signals while the vehicle is operating under cruise control, this buzzer sounds to inform the driver.
      Master Warning Light Comes on when there is a malfunction in the system.
      Steering Sensor Detects the angle and direction of steering and transmits signals to the skid control ECU and millimeter wave radar sensor assembly.

      Airbag Sensor Assembly


      • Yawrate Sensor

      		 Detects the yaw rate of the vehicle and transmits signals to the millimeter wave radar sensor assembly.
      Stop Light Switch Assembly Detects brake pedal depression and transmits its signal to the ECM.
      Brake Actuator Assembly Skid Control ECU

      • While the system is operating in vehicle-to-vehicle distance control mode, the skid control ECU operates the brake actuator in accordance with the brake request signal received from ECM.

      • Applies the brakes in accordance with signals from the ECM.
      Parking Brake ECU During stop retention control, when parking brake ECU detects that the vehicle is parked through a driver side courtesy light switch signal or driver side seat belt buckle switch signal, or an electric parking brake switch assembly signal is input, the parking brake ECU operates the parking brake, then the dynamic radar cruise control system is canceled.
      Electric Parking Brake Switch Assembly sends a parking brake application signal to the parking brake ECU.
      Parking Brake Actuator Assembly Operates the parking brake actuator assembly according to signals from the parking brake ECU.
      Speed Sensor Detects the wheel speed and transmits signals to the skid control ECU.
      ECM

      • Controls the dynamic radar cruise control system in accordance with signals from switches, sensors, and the millimeter wave radar sensor assembly.

      • If the ECM detects a malfunction in the cruise control system, it will store Diagnostic Trouble Codes (DTCs).
      Throttle Body with Motor Assembly Throttle Control Motor Adjusts the throttle valve opening angle in accordance with signals from the ECM.
      Throttle Position Sensor Detects the throttle valve opening angle and outputs it to the ECM.
      Park/Neutral Position Switch Assembly Detects the shift lever position and transmits signals to the ECM.
      Shift Paddle Switch (Transmission Shift Switch Assembly)*1 While the vehicle is being driven in D mode or S mode, this switch outputs a signal to the ECM when the switch is pulled to "+" or "-".

      Shift Lock Control Unit Assembly


      • Transmission Control Switch

      • Detects the shift lever position and transmits signals to the ECM.

      • Informs the ECM of driver upshift or downshift operations while the shift lever is in S.
      Accelerator Pedal Sensor Assembly Detects the accelerator pedal depression angle and transmits it to the ECM.
      VSC OFF Switch Detects the VSC OFF or TRC OFF signals and outputs it to the skid control ECU.
      Meter Mirror Sub-assembly*2 The headup display receives signals from the combination meter assembly in order to display the system conditions.
      Central Gateway ECU (Network Gateway ECU) Gateway function of CAN communication.

      *1: Models with shift paddle switch (transmission shift switch assembly)

      *2: Models with headup display

  2. FUNCTION


    1. Function List


      1. The control of the dynamic radar cruise control system varies depending on the mode:

        A: Constant Speed Control Mode

        B: Vehicle-to-vehicle distance control mode

        Function Outline Mode
        A B
        Constant Speed Control The ECM compares the actual vehicle speed and the set speed and if the vehicle speed is lower than the set speed, it uses the throttle motor to increase the throttle valve opening angle. ○ ○
        Deceleration Control Performs throttle control and brake control in order to decelerate the vehicle so that the vehicle-to-vehicle distance between the driver's own vehicle and the vehicle ahead equals the set distance. - ○
        Follow-up Control After performing deceleration control, the driver's own vehicle follows the vehicle ahead in order to maintain the proper vehicle-to-vehicle distance in accordance with the vehicle speed. - ○
        Acceleration Control Accelerates the vehicle in order to attain the set vehicle speed if the vehicle ahead or the driver's own vehicle has changed lanes. - ○
        Stop Control Detects if the vehicle ahead has stopped, performs motive force control and stops the vehicle while maintaining proper vehicle-to-vehicle distance. - ○
        Stop Retention Control Judges if the vehicle is stopped, performs brake control and keeps the vehicle stopped through the brake hold function. - ○
        Start Control Detects that the vehicle ahead starts moving again, displays the message on the multi-information display to urge the driver to perform the start-off operation (to operate the cruise control main switch or depress the accelerator pedal), and resumes follow-up control after the vehicle is started. - ○
        Set Control When the dynamic radar cruise control system has been turned on using the cruise control switch on the steering pad switch assembly, either of the relevant vehicle speed conditions shown below is met, and the -SET switch on the steering pad switch assembly is pressed, the ECM stores the vehicle speed and maintains the vehicle constantly at that speed. ○ ○
        The vehicle is being driven at a speed of approximately 40 km/h to 200 km/h (25 mph to 125 mph). ○ -
        The vehicle is traveling at a speed within the range of approximately 50 km/h to 180 km/h (30 mph to 110 mph). - ○
        Low Speed Limit Control The low speed limit is the lowest speed that cruise control can be set at and it is designed to be approximately 40 km/h (25 mph). The cruise control cannot be set below that speed. If the vehicle speed drops below that speed while driving using cruise control, the cruise control will be canceled automatically. The set vehicle speed is kept in memory. ○ ○
        COAST Control While the -SET switch on the steering pad switch assembly is pushed continuously, the vehicle speed and the set vehicle speed change as follows, according to the mode: ○ ○

        • The vehicle decelerates constantly.

        • The set vehicle speed changes to the speed at which the -SET switch is released.

        		 ○ -

        • The set vehicle speed decreases in increments of 5 km/h or 5 mph. [Example: 103 → 100 → 95 → 90 → 85 km/h (mph)]

        • The vehicle decelerates rapidly. The vehicle will remain at the speed that the vehicle is traveling at when the -SET switch is released.

        		 - ○
        Tap Down Control When the -SET switch on the steering pad switch assembly is pushed momentarily (approximately 0.6 seconds or less), the vehicle speed and the set vehicle speed change as follows, according to the mode: ○ ○

        • The vehicle will decelerate in increments of approximately 1 km/h or 1 mph each time the -SET switch is pushed.

        • However, if the difference between the actual vehicle speed and the set vehicle speed is greater than 5 km/h (3 mph), the set vehicle speed will change to the speed at which the vehicle was being driven at the time the -SET switch was operated.

        		 ○ -
        The vehicle will decelerate in increments of approximately 1 km/h or 1 mph for each time the -SET switch is pushed. - ○
        Accelerator Control While the +RES switch on the steering pad switch assembly is pushed continuously, the vehicle speed and the set vehicle speed change as follows, according to the mode: ○ ○

        • The vehicle will accelerate constantly.

        • The set vehicle speed changes to the speed at which the +RES switch is released.

        		 ○ -

        • The set vehicle speed increases in increments of 5 km/h or 5 mph. [Example: 83 → 85 → 90 → 95 → 100 km/h (mph)]

        • The vehicle will accelerate to the speed that is set at the time the +RES switch is released. However, only the set vehicle speed will change during follow-up control.

        		 - ○
        Resume Control If the vehicle speed is above the low speed limit, the +RES switch on the steering pad switch assembly can be pushed to resume cruise control operation and reach the vehicle speed that was set at the time the driver canceled cruise control. ○ ○
        Even if the vehicle speed drops below the low speed limit, resumption can be performed when the vehicle speed increases to above the low speed limit. However, resumption can be performed even if the vehicle speed is below the low speed limit when the vehicle is running in mode B and there is a vehicle ahead. - ○
        If the vehicle ahead changes driving lanes during follow-up control, the vehicle speed is gradually increased to the set vehicle speed. At this time, the vehicle speed can be increased promptly by pushing the +RES switch on the steering pad switch assembly. - ○
        After the vehicle ahead has started running again under stop retention control and then the message that urges the driver to perform the start-off operation has been displayed, when the cruise control main switch is pushed to the +RES side, follow-up control is resumed and the vehicle can be accelerated up to the set speed. - ○
        Tap Up Control When the +RES switch on the steering pad switch assembly is pushed momentarily (approximately 0.6 seconds or less), the vehicle speed and the set vehicle speed change as follows: ○ ○

        • The vehicle will accelerate in increments of approximately 1 km/h or 1 mph for each time the +RES switch was pushed.

        • However, if the difference between the actual vehicle speed and the set vehicle speed is greater than 5 km/h (3 mph), the set vehicle speed will not change.

        		 ○ -
        The vehicle will accelerate in increments of approximately 1 km/h or 1 mph for each time the +RES switch is pushed. - ○
        Shift-down Control When the vehicle is traveling uphill using cruise control, automatic transmission control may cause the transmission to shift down. During shift down control, when the end of uphill travel is determined based on the throttle valve angle, the transmission will shift up after a certain period of time. When the transmission shifts down during accelerator control or resume control, the transmission will shift up after accelerator control or resume control ends. ○ ○
        Manual Cancel Control

        If any of the following signals are sent to the ECM, the cruise control is canceled accordingly:


        • Stop light switch on signal (The brake pedal is depressed.)

        • Shift lever is moved from D or S to any other position.

        • When 1st, 2nd or 3rd range is selected in D position by shift paddle switch (Transmission shift switch assembly).*

        • CANCEL switch on signal (CANCEL switch on the steering pad switch assembly is pushed).

        • Cruise control switch (ON-OFF switch) off signal sent to the ECM.

        		 ○ ○
        Automatic Cancel Control When an automatic cancel signal is sent to the ECM, cruise control operation is canceled. At this time, the type of warning sent to the driver and the control resumption condition varies according to the cancel signal. ○ ○
        Mode Switching Control

        The following operations switch modes:


        • Vehicle-to-vehicle distance control mode is activated immediately after the switch is turned on. The mode is changed to constant speed control mode by pressing and holding the switch for more than 1.5 seconds while the dynamic radar cruise control system is turned off.

        		 ○ ○
        Other Cancel Conditions

        • VSC operates during cruise control driving.

        • TRC operates for a certain period of time while the cruise control.

        • TRC is off or VSC is off.

        • Ignition switch off.

        • DSC operates during cruise control driving.

        • Parking brake operates during cruise control driving.

        		 ○ ○
        Diagnosis If a malfunction occurs in the dynamic radar cruise control system during cruise control operation, the ECM cancels cruise control and memorizes information related to the malfunction. ○ ○

        *: Models with shift paddle switch (transmission shift switch assembly)

        ○: Available

        -: Not Available

    2. Constant Speed Control Mode


      1. The ECM compares the set vehicle speed and the actual vehicle speed, and performs constant speed control by regulating the throttle in order to attain the set vehicle speed. The ECM compares the set vehicle speed and the actual vehicle speed, and performs constant speed control by regulating the throttle in order to attain the set vehicle speed. The millimeter wave radar sensor assembly uses the millimeter wave radar sensor signal and information from the forward recognition camera to determine the condition in front of the vehicle and sends acceleration/deceleration requests to the ECM.

        B006WFCE02

    3. Vehicle-to-vehicle Distance Control Mode


      • In vehicle-to-vehicle distance control mode, the ECM performs deceleration control function, follow-up control function, acceleration control function, stop control function, stop retention control function or start control function based on the information about the vehicle ahead transmitted from the millimeter wave radar sensor assembly and forward recognition camera.


      1. Deceleration Control


        • The millimeter wave radar sensor assembly calculates the target deceleration rate in accordance with signals from the millimeter wave radar sensor, forward recognition camera and transmits a deceleration request signal to the ECM. Upon receiving this signal, the ECM closes the throttle valve in order to cause the vehicle to decelerate.

        • This control is not performed in the presence of a parked vehicle or object or below the settable vehicle speed range.

          B006WR6E02

        • If the millimeter wave radar sensor assembly determines that further deceleration is necessary, it transmits a brake request signal to the ECM. Upon receiving this signal, the ECM transmits a brake request signal to the skid control ECU. The skid control ECU then controls the brake actuator to apply the brakes.

        • At this time, if the deceleration rate is higher than a predetermined value, the skid control ECU outputs a stop light illumination request signal to the stop lights in order to warn any vehicles behind.

          B006WMLE02

        • If the vehicle is not decelerating adequately, the forward recognition camera sounds a meter buzzer to prompt the driver to apply the brakes.

          B006WL5E02

      2. Follow-up Control


        • After performing deceleration control, the millimeter wave radar sensor assembly transmits a request signal to the ECM so that the vehicle can follow the vehicle ahead while maintaining the proper vehicle-to-vehicle distance according to the vehicle speed. Upon receiving this signal, the ECM regulates the throttle in order to perform follow-up control.

        • 3 stages (long, middle and short) of vehicle-to-vehicle distance can be selected by operating the vehicle-to-vehicle distance control switch.

          B006WD0E02

      3. Acceleration Control


        • If the millimeter wave radar sensor assembly detects (based on the millimeter wave radar sensor and forward recognition camera) that either the vehicle ahead or the driver has changed lanes, an acceleration request signal is transmitted to the ECM in order to attain the set vehicle speed. Upon receiving this signal, the ECM regulates the throttle in order to perform acceleration control.

          B006WGVE02

      4. Stop Control Function


        • During vehicle-to-vehicle distance control mode, if the vehicle ahead stops, the millimeter wave radar sensor assembly maintains an appropriate vehicle-to-vehicle distance while at the same time calculating the necessary driving force to stop the vehicle, and sends a drive request signal to the ECM and skid control ECU. When the ECM and skid control ECU receive this signal, they control the driving force and stop the vehicle.

        • At this time, the skid control ECU outputs a stop light illumination request signal in order to inform anyone who might be following the vehicle.

        • The distance between the driver's own vehicle and the preceding vehicle when the vehicles are stopped is set to approximately 5 m to 7 m (16 ft. to 23 ft.) regardless of the vehicle-to-vehicle distance preset by using the distance control switch.

          B006WG5E01

      5. Stop Retention Control Function


        • After the vehicle has stopped under stop control, the ECM transmits a stop retention request signal to the skid control ECU. Upon receiving this signal, the skid control ECU activates the brake hold function and keeps the vehicle stopped.

          B006WEHE01

      6. Start Control Function


        • When the millimeter wave radar sensor assembly detects that the vehicle ahead starts moving again millimeter wave radar sensor assembly and forward recognition camera signal, it displays the messages on the multi-information display and headup display* to urge the driver to perform the start-off operation (to push the cruise control main switch to the +RES side or to depress the accelerator pedal).

          *: Models with headup display

        • Upon receiving the start-off operation signal generated by pushing the +RES switch on the steering pad switch assembly or by depressing the accelerator pedal, the millimeter wave radar sensor assembly transmits a motive force request signal to the ECM. Upon receiving this signal, the ECM controls the motive force, starts the vehicle and resumes follow-up control.

        • During idle stop status, engine starts automatically when the ECU detects the movement of preceding vehicle.

          B006WM8E01

    4. Automatic Cancel Control


      1. If one of the conditions listed below occurs while the vehicle is being driven using cruise control, speed control by the cruise control system will be canceled. Then, the following warning items will appear for the driver.

        Constant Speed Control Mode
        Situation Warning
        Multi-information Display B006WHW Buzzer

        If the conditions listed below occurs, the ECM clears the set vehicle speed and cancels the cruise control.


        • An open or short circuit in the stop light switch assembly.

        Speed control by the dynamic radar cruise control system is disabled until the conditions are corrected or the dynamic radar cruise control system is turned off and back on again using the cruise control switch on the steering pad switch assembly.

        Cruise Control

        Malfunction

        Visit Your

        Dealer

        		 Illuminates Sounds

        If either of the following conditions occurs, the ECM cancels the cruise control.


        • Stop light switch assembly input signal is abnormal.

        • Cancel circuit malfunction.

        • Brake control system malfunction.

        • Communication malfunction between the skid control ECU and ECM.

        Speed control by the cruise control system is disabled until the ignition switch is turned ON again.

        Cruise Control

        Malfunction

        Visit Your

        Dealer

        		 Illuminates Sounds

        If the following condition occurs, the ECM cancels the cruise control while retaining the set vehicle speed in its memory.


        • The vehicle speed drops below the low speed limit [approximately 40 km/h (25 mph)].

        		 - Does not illuminate -

        If the following condition occurs, the ECM clears the set vehicle speed and cancels the cruise control.


        • The vehicle speed drops more than 16 km/h (10 mph) below the set vehicle speed.

        		 - Does not illuminate -

        If the following condition occurs, the ECM clears the set vehicle speed and cancels the cruise control.


        • Malfunction in engine control system.

        Speed control by the dynamic radar cruise control system is disabled until the condition is corrected or the dynamic radar cruise control system is turned off and back on again using the cruise control switch on the steering pad switch assembly.

        		 - Illuminates -

        If either of the conditions listed below occurs, the ECM clears the set vehicle speed and cancels speed control by the cruise control system.


        • VSC operates during cruise control driving.

        • TRC operates for a certain period of time during cruise control driving.

        • TRC is off or VSC is off.

        • DSC operates during cruise control driving.

        		 - Does not illuminate -
        Vehicle-to-vehicle Distance Control Mode
        Situation Warning
        Multi-information Display B006WHW Buzzer

        If the conditions listed below occurs, the ECM clears the set vehicle speed and cancels the cruise control.


        • An open or short circuit in the stop light switch assembly.

        Cruise control is prohibited until the normal operating conditions are met or the dynamic radar cruise control system is turned off and back on again using the cruise control switch on the steering pad switch assembly.

        Cruise Control

        Malfunction

        Visit Your

        Dealer

        		 Illuminates Sounds

        If one of the conditions listed below occurs, the ECM clears the set vehicle speed and cancels the cruise control.


        • Malfunction of the millimeter wave radar sensor assembly.

        • Misalignment of the axis of the millimeter wave radar sensor assembly.

        • Malfunction in the dynamic radar cruise control system other than those given above.

        • Stop light switch assembly input signal is abnormal.

        • Cancel circuit malfunction.

        Speed control by the cruise control system is disabled until the ignition switch is turned ON again.

        Cruise Control

        Malfunction

        Visit Your

        Dealer

        		 Illuminates Sounds

        If the following condition occurs, the ECM clears the set vehicle speed and cancels the cruise control.


        • Malfunction in engine control system.

        Speed control by the dynamic radar cruise control system is prohibited until the condition is corrected or the dynamic radar cruise control system is turned off and back on again using the cruise control switch on the steering pad switch assembly.

        		 - Illuminates -

        If the following condition occurs, the ECM cancels the cruise control while retaining the set vehicle speed in its memory.


        • The millimeter wave radar sensor assembly or the emblem are dirty.

        Speed control by the dynamic radar cruise control system is prohibited until the condition is corrected or the dynamic radar cruise control system is turned off and back on again using the cruise control switch on the steering pad switch assembly.

        Radar Cruise

        Control

        Unavailable

        Clean Sensor

        		 Illuminates Sounds

        If either of the following conditions occurs, the ECM cancels the cruise control while retaining the set vehicle speed in its memory.


        • The measurement becomes extremely unstable due to poor weather conditions.

        • Brake control by the dynamic radar cruise control system is temporarily unavailable.

        • Misalignment of the axis of the millimeter wave radar sensor assembly.

        • A Malfunction in the forward recognition camera.

        • Forward recognition camera temporarily not available.

        Speed control by the dynamic radar cruise control system is prohibited until the condition is corrected or the dynamic radar cruise control system is turned off and back on again using the cruise control switch on the steering pad switch assembly.

        Radar Cruise

        Control

        Unavailable

        		 Illuminates Sounds

        If the following condition occurs, the ECM cancels the cruise control while retaining the setting vehicle speed in its memory.


        • The vehicle speed drops below the low speed limit [approximately 40 km/h (25 mph)].

        		 - Does not illuminate

        Sounds

        Twice

        If either of the conditions listed below occurs, the ECM clears the set vehicle speed and cancels speed control by the cruise control system.


        • VSC operates during cruise control driving.

        • TRC operates for a certain period of time during cruise control driving.

        • TRC is off or VSC is off.

        • DSC operates during cruise control driving.

        • Electric parking brake operates.

        		 - Does not illuminate -

        If any of the following conditions occur while the vehicle stopped, the ECM cancels control of vehicle speed by the dynamic radar cruise control system.


        • The driver seat belt is unfastened.

        • The driver door is opened.

        • The vehicle is parked for a long period of time.

        • The vehicle is driving on as steep hill.

        • A preceding vehicle is not detected.

        		 Radar Cruise Control Unavailable Press Brake to Resume Driving Does not illuminate -

        If either of the conditions listed below occurs, the ECM cancels speed control by the cruise control system while retaining the set vehicle speed in its memory.


        • Stop light switch assembly input signal is abnormal.

        • Malfunction in the millimeter wave radar sensor assembly.

        • Beam axis of millimeter wave radar sensor assembly misaligned.

        • The electric parking brake system is malfunctioning.

        • An open or short circuit in the stop light switch.

        • Problem with cruise control main switch cancel circuit.

        • Millimeter wave radar sensor assembly becomes dirty.

        • Brake control by the dynamic radar cruise control system is temporarily unavailable.

        • The forward recognition camera is temporarily unavailable.

        		 Cruise Control Fault Press Brake to Deactivate Visit Your Dealer Illuminates Sounds

  3. DIAGNOSIS


    1. If a malfunction occurs in the dynamic radar cruise control system during cruise control operation, the ECM automatically cancels the cruise control, illuminates the master warning light, sounds a buzzer in the combination meter assembly, and displays a warning message on the multi-information display to inform the driver of the malfunction. At this time, the ECM memorizes the malfunction in the form of a Diagnostic Trouble Codes (DTCs).

    2. The DTCs can be read by connecting the Global TechStream (GTS) to the DLC3. For details, refer to the Repair Manual.