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 ahead, the vehicle-to-vehicle distance, the relative speed and direction then transmits this information to the driving support ECU assembly.
      Forward Recognition Camera (Camera Sensor)

      • Detects lane markers and objects on the road ahead using the image captured by the monocular camera and sends the information to the driving support ECU assembly.

      • Transmits an operation signal to the camera heater.*1
      Camera Heater (Forward Recognition Hood with Heater Sub-assembly)*1 The camera heater is heated according to signals from the forward recognition camera.
      Accelerator Pedal Sensor Assembly Detects the accelerator pedal depression angle and transmits it to the ECM.
      Spiral Cable with Sensor Sub-assembly Steering Angle Sensor Detects the angle and direction of steering and transmits signals to the driving support ECU assembly.
      Yawrate Sensor Detects the yaw rate of the vehicle and transmits signals to the driving support ECU assembly.
      Speed Sensor Detects the wheel speed and transmits signals to the skid control ECU.
      Cruise Control Main Switch ON-OFF Button

      • Turns the cruise control system on and off.

      • Selects the vehicle-to-vehicle distance control mode and constant speed control mode.
      CANCEL Switch A cancel signal is output to the driving support ECU assembly 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 driving support ECU assembly when this switch is operated.
      -SET Switch The deceleration function and vehicle speed setting resume signals are output to the driving support ECU assembly when this switch is operated.
      Steering Pad Switch Assembly Distance Control Switch While the system is in vehicle-to-vehicle distance control mode, the driver can operate the distance control switch to select the vehicle-to-vehicle distance in three levels: long, middle and short.
      Park/Neutral Position Switch Assembly Detects the shift lever position and transmits signals to the ECM.
      Stop Light Switch Assembly Detects brake pedal depression and transmits a signal to the driving support ECU assembly and skid control ECU.
      Transmission Floor Shift 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 M.
      Shift Paddle Switch (Transmission Shift Switch Assembly) Informs the ECM of driver upshift or downshift operations.
      Integration Control and Panel Assembly VSC OFF Switch Detects the VSC off signal and outputs it to the skid control ECU.
      Combination Switch Assembly SNOW Mode Switch*2 Detects the switch operation signal and through the ECM transmits a signal to the driving support ECU assembly.
      Driving Support ECU Assembly

      • Calculates the acceleration or deceleration required to achieve the target vehicle speed/target vehicle-to-vehicle distance based on signals from switches, sensors and ECUs, and transmits acceleration or deceleration request signals to the ECM (to accelerate the vehicle) and/or the skid control ECU (to decelerate the vehicle).

      • Determines the presence of a preceding vehicle based on information from the millimeter wave radar sensor assembly and the forward recognition camera (camera sensor).

      • Transmits control status display request signals, warning display request signals and diagnosis signals for the dynamic radar cruise control system.
      ECM

      • Actuates the throttle motor in accordance with the signals from the driving support ECU assembly.

      • Converts the motive force request signal from the driving support ECU assembly into the acceleration request signal and outputs it to the skid control ECU.
      Brake Actuator Assembly Skid Control ECU

      • While the system is operating in vehicle-to-vehicle distance control mode, the skid control ECU performs brake control in accordance with request signals from the ECM.

      • Transmits signals such as wheel speed and estimated vehicle acceleration to the driving support ECU assembly.

      • Illuminates the stop lights during brake control.
      Combination Meter Assembly Radar Cruise Control Indicator Light

      • Comes on when vehicle-to-vehicle distance control mode is entered.

      • Turns off if a malfunction occurs during vehicle-to-vehicle distance control mode control.
      Cruise Control Indicator Light

      • Comes on when constant speed control mode is entered.

      • Turns off if a malfunction occurs during constant speed control mode control.
      Cruise SET Indicator Light Illuminates when the vehicle speed is set.
      Master Warning Light Illuminates when a system malfunction occurs.
      Multi-information Display During dynamic radar cruise control operation, the multi-information display receives signals from the driving support ECU assembly in order to display the system conditions.
      Buzzer If the driving support ECU assembly detects automatic cancel or warning signals while the vehicle is operating under cruise control, this buzzer sounds once to inform the driver.
      Combination Meter Mirror Assembly*3 When the head-up display is operated, displays the vehicle approach warning in head-up display due to the signal from the combination meter assembly.
      TCM Performs downshifts and upshifts according to signals from the ECM.
      Network Gateway ECU Relays and transmits each CAN communication data signal.
      Driving Support Buzzer (Skid Control Buzzer) Sounds a buzzer when it receives a signal from the driving support ECU assembly to alert the driver that the distance between vehicles is short.
      Throttle Body with Motor Assembly Throttle 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.

      *1: Models with camera heater

      *2: Except models for G.C.C. countries

      *3: Models with head-up 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 driving support ECU assembly compares the actual vehicle speed and the set speed. When the vehicle speed is higher than the set speed, it uses the throttle motor to decrease the throttle opening. When the actual vehicle speed is lower than the set speed, it uses the throttle motor to increase the throttle opening. ○ ○
        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. - ○
        Set Control

        When the following conditions are met, and the cruise control main switch is pressed to the -SET side and released, the driving support ECU assembly stores the vehicle speed and maintains the vehicle constantly at the current speed.


        • The cruise control system is on.

        • The shift lever is in D.

        • The shift lever is in D and the 4th or higher shift range has been selected by shift paddle switch (transmission shift switch assembly) operation.

        		 ○ ○
        The vehicle is traveling at a speed within the range of approximately 50 km/h (30 mph) to 200 km/h (125 mph). ○ -
        The vehicle is traveling at a speed within the range of approximately 50 km/h (30 mph) to 180 km/h (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 system cannot be set below that speed. If the vehicle speed drops below that speed while driving using cruise control, the cruise control system will be canceled automatically. The set vehicle speed is kept in memory. ○ ○
        COAST Switch Control While the cruise control main switch is held to the -SET side, 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 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 due to ETCS-i. The vehicle will remain at the speed that the vehicle is traveling at when the COAST switch is released.

        		 - ○
        Tap Down Control When the cruise control main switch is moved momentarily (approximately 0.6 seconds or less) to the -SET side, the vehicle speed and the set vehicle speed change as follows, according to the mode: ○ ○

        • The vehicle will decelerate in increments of approximately 1.6 km/h or 1 mph each time the switch is moved.

        • 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 switch was operated.

        		 ○ -

        • The vehicle will decelerate in increments of approximately 5 km/h or 5 mph each time the switch is moved. (Models for Europe)

        • The vehicle will decelerate in increments of approximately 1 km/h or 1 mph each time the switch is moved. (Except models for Europe)

        		 - ○
        ACC Switch Control When the cruise control main switch is held to the +RES side, 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 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 switch is released. However, only the set vehicle speed will change during follow-up control.

        		 - ○
        Tap Up Control When the cruise control main switch is moved momentarily (approximately 0.6 seconds or less) to the +RES side, the vehicle speed and the set vehicle speed change as follows, according to the mode: ○ ○

        • The vehicle will accelerate in increments of approximately 1.6 km/h or 1 mph each time the switch is moved.

        • 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 5 km/h or 5 mph each time the switch is moved. (Models for Europe)

        • The vehicle will accelerate in increments of approximately 1 km/h or 1 mph each time the switch is moved. (Except models for Europe)

        		 - ○
        RES Switch Control When the vehicle speed is above the low speed limit, the cruise control system resumes operation (when the cruise control main switch is subsequently pushed to the +RES side) to reach the vehicle speed that was set at the time the driver canceled cruise control. ○ ○
        When the vehicle ahead changes driving lanes during follow-up control, the vehicle speed is gradually increased to the set speed. At this time, the vehicle speed can be increased promptly by pushing the cruise control main switch to the +RES direction. - ○
        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 ACC switch control or RES switch control, the transmission will shift up after ACC switch control or RES switch control ends. ○ ○
        Manual Cancel Control

        If one of the following conditions is met, the cruise control system is canceled accordingly.


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

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

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

        • CANCEL switch on signal. (The cruise control main switch is moved to CANCEL side.)

        • Cruise control main switch (ON-OFF button) off signal.

        		 ○ ○
        Automatic Cancel Control When an automatic cancel signal is sent to the driving support ECU assembly, 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 Selecting Control The constant speed control mode can be selected by press and holding the operating the cruise control main switch ON-OFF button for approximately more than 1.5 seconds. ○ -
        The vehicle-to-vehicle distance control mode can be selected by short pressing and operating the cruise control main switch ON-OFF button for approximately 1.5 seconds or less. - ○
        Other Cancellation Conditions

        If any of the following conditions occurs during cruise control driving, the cruise control system is canceled.


        • VSC operates during cruise control driving.

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

        • TRAC is off or VSC is off. (The set vehicle speed remains in the memory.)

        • If the parking brake is operated.

        		 ○ ○

        Tech Tips

        ○: Available

        -: Not Available

    2. Constant Speed Control Mode


      1. The driving support ECU assembly compares the actual vehicle speed (wheel speed signal from the skid control ECU) with the set vehicle speed under constant speed control in each control mode. When the actual vehicle speed differs from the set vehicle speed, the driving support ECU assembly calculates the motive force required to achieve the set vehicle speed and transmits motive force request signals to the ECM, thus controlling the motive force optimally and adjusting the actual vehicle speed to the set vehicle speed.

        B002AV3E01

    3. Deceleration Control Function (Vehicle-to-vehicle Distance Control Mode)


      1. The driving support ECU assembly calculates the target deceleration rate in accordance with signals from the millimeter wave radar sensor assembly and the forward recognition camera (camera sensor), and transmits a motive force request signal to the ECM.

      2. The ECM closes the throttle valve upon receiving this signal in order to cause the vehicle to decelerate.

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

        B002AU6E01

      4. If the driving support ECU assembly determines that further deceleration is necessary, the ECM converts the motive force request signal received from the driving support ECU assembly into an acceleration request signal and sends it to the skid control ECU. After receiving the acceleration request signal, the skid control ECU controls the brake actuator to apply the brakes.

      5. 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 light, in order to warn any vehicles behind.

        B002AUCE01

      6. If the vehicle is not decelerating adequately, the driving support ECU assembly sounds the driving support buzzer (skid control buzzer) to urge the driver to depress the brake pedal.

        B002AT8E01

    4. Follow-up Control Function (Vehicle-to-vehicle Distance Control Mode)


      1. After performing deceleration control, the driving support ECU assembly transmits a motive force 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.

      2. The ECM regulates the throttle upon receiving this signal in order to perform follow-up control.

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

        B002AR2E01

    5. Acceleration Control Function (Vehicle-to-vehicle Distance Control Mode)


      1. If the driving support ECU assembly detects (based on the millimeter wave radar sensor assembly and the forward recognition camera (camera sensor)) that either the vehicle ahead or the driver has changed lanes, a motive force request signal is transmitted to the ECM in order to attain the set vehicle speed. Upon receiving this signal, the ECM controls is the motive force in order to perform acceleration control.

        B002AV7E01

    6. Automatic Cancel Control Function


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

        Vehicle-to-vehicle Distance Control Mode
        Situation Warning
        Multi-information Display Indication B002AQ9 Buzzer B002ASF

        If the condition listed below occurs, the driving support ECU assembly clears the set vehicle speed and cancels the cruise control system.


        • Stop light switch open or short circuit.

        The cruise control system is disabled until the conditions are corrected or the cruise control system is turned off and back on again using the ON-OFF button on the cruise control main switch.

        		 "Cruise Control Malfunction Visit Your Dealer" Illuminates Sounds once Does not illuminate

        If any of the conditions listed below occurs, the driving support ECU assembly clears the set vehicle speed and cancels the cruise control system.


        • 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.

        The cruise control system is disabled until the engine switch is turned on (IG) again.

        		 "Cruise Control Malfunction Visit Your Dealer" Illuminates Sounds once Does not illuminate

        If the condition listed below occurs, the driving support ECU assembly cancels the cruise control system while retaining the set vehicle speed in its memory.


        • The millimeter wave radar sensor assembly or radiator grille (or front panel) emblem becomes contaminated with dirt.

        The cruise control system is disabled until the conditions are corrected or the cruise control system is turned off and back on again using the ON-OFF button on the cruise control main switch.

        		 "Radar Cruise Control Unavailable Clean Sensor" Illuminates Sounds once Does not illuminate

        If any of the conditions listed below occurs, the driving support ECU assembly cancels the cruise control system while retaining the set vehicle speed in its memory.


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

        • If the brakes cannot be used temporarily.

        • If the optical axis slippage of the millimeter wave radar sensor assembly is doing an auto-correction.

        • If the forward recognition camera (camera sensor) is damaged or cannot be used temporarily.

        • If SNOW mode* is selected.

        The cruise control system is disabled until the conditions are corrected or the cruise control system is turned off and back on again using the ON-OFF button on the cruise control main switch.

        		 "Radar Cruise Control Unavailable" Illuminates Sounds once Does not illuminate

        If the condition listed below occurs, the driving support ECU assembly cancels the cruise control system 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 Sounds twice Illuminates

        *: Except models for G.C.C. countries

        Constant Speed Control Mode
        Situation Warning
        Multi-information Display Indication B002AQ9 Buzzer B002AW5

        If the condition listed below occurs, the driving support ECU assembly clears the set vehicle speed and cancels the cruise control system.


        • Stop light switch open or short circuit.

        The cruise control system is disabled until the conditions are corrected or the cruise control system is turned off and back on again using the ON-OFF button on the cruise control main switch.

        		 "Cruise Control Malfunction Visit Your Dealer" Illuminates - Does not illuminate

        If the condition listed below occurs, the driving support ECU assembly clears the set vehicle speed and cancels the cruise control system.


        • Engine control system malfunction.

        The cruise control system is disabled until the conditions are corrected or the cruise control system is turned off and back on again using the ON-OFF button on the cruise control main switch.

        		 - Does not illuminate - Does not illuminate

        If the condition listed below occurs, the driving support ECU assembly cancels the cruise control system 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 - Illuminates

        If the condition listed below occurs, the driving support ECU assembly clears the set vehicle speed and cancels the cruise control system. However, the cruise control system and vehicle speed can be set again.


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

        		 - Does not illuminate - Illuminates

  3. DIAGNOSIS


    1. If a malfunction occurs in the dynamic radar cruise control system during cruise control operation, the driving support ECU assembly automatically cancels the cruise control system, illuminates the master warning light, sounds a buzzer and displays "Cruise Control Malfunction Visit Your Dealer" on the multi-information display to inform the driver of the malfunction. At this time, the malfunction is stored in memory as a 5-digit Diagnostic Trouble Code (DTC).

    2. The DTC can be read when the Global TechStream (GTS) is connected to the DLC3. For details, refer to the Repair Manual.