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
      Cruise Control Main Switch ON-OFF/Mode Button

      • Turns the cruise control system on and off.

      • Vehicle-to-vehicle distance control mode is activated immediately after the main switch is turned on. The mode shifts to constant speed control mode by pressing and holding the button more than 1.5 sec.
      CANCEL Switch A cancel signal is output to the hybrid vehicle control ECU when this switch is operated.
      +RES Switch Acceleration and resuming of a preset speed can be performed by operating this switch. A signal is output to the hybrid vehicle control ECU when this switch is operated.
      -SET Switch The deceleration function is operated and vehicle speed setting signals are output to the hybrid vehicle control ECU when this switch is operated.
      Steering Pad Switch Assembly 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 1 of 3 levels for the vehicle-to-vehicle distance: long, middle and short.
      Hybrid Vehicle Control ECU

      • Controls the dynamic radar cruise control system in accordance with signals from the switches, sensors, skid control ECU and driving support ECU assembly.

      • If the hybrid vehicle control ECU detects a malfunction in the cruise control system, it will store Diagnostic Trouble Codes (DTCs).
      Stop Light Switch Assembly Detects the depression of the brake pedal and transmits a signal to the hybrid vehicle control ECU.
      Millimeter Wave Radar Sensor Assembly Radiates millimeter waves forward, uses the reflected waves to detect the presence of a vehicle traveling ahead, the vehicle-to-vehicle distance, and the relative speed, and then transmits this information to the driving support ECU assembly.
      Driving Support ECU Assembly While the system is in the vehicle-to-vehicle distance control mode, the driving support ECU assembly detects the vehicle being followed based on signals from the millimeter wave radar sensor assembly and pre-crash safety city sensor (forward recognition camera). Then, the driving support ECU 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 hybrid vehicle control ECU.
      ECM Actuates the throttle control motor in accordance with the signals from the hybrid vehicle control ECU.
      Inverter with Converter Assembly MG ECU Built into the inverter with converter assembly. Controls the motive force of motor generators in accordance with signals from the hybrid vehicle control ECU.
      Hybrid Vehicle Transaxle Assembly MG2 Generates motive force for the wheels.
      Combination Meter Assembly Cruise Control Indicator Light (Constant Speed Control Mode)

      • Based on a cruise control indicator light operation signals sent by the hybrid vehicle control ECU, the combination meter assembly illuminates the cruise control indicator light when the cruise control system has been turned on using the ON-OFF button on the cruise control main switch and constant speed control mode has been selected.

      • Based on a cruise control indicator light operation signals sent by the hybrid vehicle control ECU, the combination meter assembly turns off the radar cruise control indicator light if a malfunction occurs in the cruise control system.
      Radar Cruise Control Indicator Light (Vehicle-to-vehicle Distance Control Mode)

      • Based on a radar cruise control indicator light operation signals sent by the hybrid vehicle control ECU, the combination meter assembly illuminates the radar cruise control indicator light when the cruise control system has been turned on using the ON-OFF button on the cruise control main switch.

      • Based on a radar cruise control indicator light operation signals sent by the hybrid vehicle control ECU, the combination meter assembly turns off the radar cruise control indicator light if a malfunction occurs in the cruise control system.
      Cruise Control SET Indicator Light Illuminates when the vehicle speed is set.
      Buzzer If the hybrid vehicle control ECU detect automatic cancellation or warning signals while the vehicle is operating under cruise control, this buzzer sounds to inform the driver.
      Master Warning Light Illuminates when there is a malfunction in the system.
      Multi-information Display During dynamic radar cruise control operation, the multi-information display receives signals from the hybrid vehicle control ECU in order to display the system conditions.
      Steering Sensor Detects the angle and direction of steering and transmits signals to the driving support ECU assembly.
      Center Airbag Sensor Assembly Yawrate Sensor Detects the yaw rate of the vehicle and transmits signals to the driving support ECU assembly.
      Brake Booster Assembly Skid Control ECU

      • While the system is operating in vehicle-to-vehicle distance control mode, the skid control ECU operates the brake booster assembly in accordance with brake request signals received from the hybrid vehicle control ECU.

      • Applies the brakes in accordance with signals from the hybrid vehicle control ECU.
      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.
      PCS Buzzer (Skid Control Buzzer) Sounds when it receives a signal from the driving support ECU assembly to alert the driver that the distance between vehicles is short.
      Accelerator Pedal Sensor Assembly Detects the accelerator pedal depression degree and outputs it to the hybrid vehicle control ECU.
      Speed Sensors Detects the wheel speed and transmits signals to the skid control ECU.
      Shift Lever Position Sensor Converts the shift position into an electrical signal and outputs it to the hybrid vehicle control ECU.
      Transmission Floor Shift Assembly Transmission Control Switch While the vehicle is being driven in S mode, this switch outputs a signal to the hybrid vehicle control ECU when the shift lever is moved toward "+" or "-".
      Forward Recognition Camera

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

      • Transmits an operation signal to the camera heater.*
      Camera Heater (Forward Recognition Hood with Heater Sub-assembly)* The camera heater is heated according to signals from the forward recognition camera.
      Telltale Light Assembly VSC OFF Switch Enables the driver to select normal mode, TRC OFF mode or VSC OFF mode.
      Central Gateway ECU Transmits signals between the CAN communication buses.

      *: Models with camera heater

  2. SYSTEM CONTROL


    1. The driving support ECU assembly, millimeter wave radar sensor assembly, forward recognition camera and hybrid vehicle control ECU control this system.

    2. The combination meter assembly informs the driver of the control conditions.

    3. Constant speed control mode is controlled by the hybrid vehicle control ECU, which outputs signals to the throttle control motor and the MG ECU.

    4. Vehicle-to-vehicle distance control mode is controlled by the millimeter wave radar sensor assembly and driving support ECU assembly, forward recognition camera, skid control ECU, hybrid vehicle control ECU and ECM. Thus, the signals are output to the actuators and the ECU while exchanging data as indicated below.

      B0020A4E01

  3. FUNCTION


    1. Control of Dynamic Radar Cruise Control System Varies Depending on Mode


      • A: Constant speed control mode

      • B: Vehicle-to-vehicle distance control mode

      Function Outline Mode
      A B
      Constant Speed Control The hybrid vehicle control ECU compares the actual vehicle speed and the set speed. If the vehicle speed is higher than the set speed, it uses the throttle control motor to decrease the throttle opening and the MG ECU to decrease the motive force of MG2. If the actual vehicle speed is lower than the set speed, it uses the throttle control motor to increase the throttle opening and the MG ECU to increase the motive force of MG2. ○ ○
      Deceleration Control Performs engine and brake control in order to decelerate the vehicle so that the vehicle-to-vehicle distance between this vehicle and the preceding vehicle equals the set distance. - ○
      Follow-up Control After performing deceleration control, the vehicle follows the preceding vehicle 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 preceding vehicle or this vehicle has changed lanes. - ○
      Set Control

      If the cruise control main switch is pressed to the -SET side and released, the hybrid vehicle control ECU stores the vehicle speed, illuminates the cruise control SET indicator light on the multi-information display and maintains the vehicle constantly at that speed.


      • The cruise control system is on.

      		 ○ ○

      • The vehicle is running at a vehicle speed of approx. 50 km/h to 200 km/h (30 mph to 125 mph) or more.

      		 ○ -

      • The vehicle is running between approx. 50 km/h and 180 km/h (30 mph and 110 mph).

      		 - ○
      Low Speed Limit Control The low speed limit is approx. 40 km/h (25 mph). If the vehicle speed drops below that speed while running under the cruise control, the cruise control will be canceled automatically. However, the set vehicle speed in the memory is kept. ○ ○
      COAST (-) Switch Control While the cruise control main switch is held to the -SET side, the vehicle speed and the set vehicle speed change in accordance with the mode as follows: ○ ○

      • 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 remains at the speed that the vehicle is traveling at when the cruise control main switch is released.

      		 - ○
      Tap-down Control When the cruise control main switch is pushed momentarily (approx. 0.6 sec.) to the -SET side, the vehicle speed and the set vehicle speed change in accordance with the mode as follows: ○ ○

      • For models for Europe, the vehicle decelerates in increments of approx. 5 km/h or 5 mph for each time the switch is pressed. [Example: 103 → 100 → 95 → 90 → 85 km/h (mph)]

      • For models other than those for Europe, the vehicle decelerates in increments of approx. 1 km/h or 1 mph for each time the switch is pressed. [Example: 103 → 102 → 101 → 100 → 99 km/h (mph)]

      		 - ○

      • The vehicle decelerates in increments of approx. 1 km/h (1 mph) for each time the switch is pressed. However, if the difference between the actual vehicle speed and the vehicle setting speed is greater than 5 km/h (3 mph), the set vehicle speed changes to the speed at which the vehicle was being driven at the time the switch was operated.

      		 ○ -
      ACC (+) Switch Control When the cruise control main switch is pushed to the +RES side and held, the vehicle speed and the set vehicle speed change in accordance with the mode as follows: ○ ○

      • The vehicle accelerates 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 pushed momentarily (approx. 0.6 sec.) to the +RES side, the vehicle speed and the set vehicle speed change in accordance with the mode as follows: ○ ○

      • For models for Europe, the vehicle accelerates in increments of approx. 5 km/h or 5 mph for each time the switch is pressed. [Example: 83 → 85 → 90 → 95 → 100 km/h (mph)]

      • For models other than those for Europe, the vehicle accelerates in increments of approx. 1 km/h or 1 mph for each time the switch is pressed. [Example: 83 → 84 → 85 → 86 → 87 km/h (mph)]

      		 - ○

      • The vehicle accelerates in increments of approx. 1 km/h (1 mph) for each time the switch is pressed.

      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.

      		 ○ -
      RES Switch Control If the vehicle speed is above the low speed limit and the cruise control main switch is subsequently pushed to the +RES side, cruise control resumes operation to reach the vehicle speed that was set at the time the driver canceled cruise control. ○ ○
      If the preceding vehicle 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 cruise control main switch to the +RES side. - ○
      Manual Cancel Control

      If any of the following conditions is met, the cruise control is canceled accordingly. However, the set speed remains in the memory:


      • On signal is sent from the stop light switch assembly (the brake pedal is depressed).

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

      • 1st, 2nd or 3rd range is selected in the S mode position.

      • On signal is sent from the CANCEL switch.

      • ON-OFF button is turned off (the set speed is not stored).

      		 ○ ○
      Automatic Cancel Control When an automatic cancel signal is sent to the hybrid vehicle control ECU, the cruise control operation is canceled. At this time, the style of the warning to the driver and the control resumption condition varies in accordance with the cancel signal. ○ ○
      Mode Switching Control

      The following operations switch modes:


      • Vehicle-to-vehicle distance control mode is activated immediately after the main switch is turned on. The mode shifts to constant speed control mode by pressing and holding the button more than 1.5 sec.

      		 ○ ○
      Other Cancel Control

      • If any of the following conditions occur during cruise control driving, the cruise control is canceled. However, the set speed remains in the memory.


        • The VSC system is activated.

        • The TRC system is activated for a period of time.

        • The VSC or TRC system is turned off by pressing the VSC OFF switch.

      • When the power switch is turned off, the set speed is not stored in the memory.

      		 ○ ○

      Tech Tips

      ○: Available

      -: Not available

    2. Constant Speed Control Mode


      1. The millimeter wave radar sensor assembly and forward recognition camera transmit information about the preceding vehicle to the driving support ECU assembly and also transmit driving support ECU assembly operation signals to the hybrid vehicle control ECU.

      2. The hybrid vehicle control ECU compares the set speed and the actual vehicle speed, and effects constant speed control by regulating the throttle control and MG2 in order to attain the set speed.

        B00208WE01

    3. Vehicle-to-vehicle Distance Control Mode


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


      1. Deceleration Control Function


        • The driving support ECU assembly calculates the target deceleration rate in accordance with signals from the millimeter wave radar sensor assembly and forward recognition camera, and transmits a deceleration request signal to the hybrid vehicle control ECU. Upon receiving this signal, the hybrid vehicle control ECU transmits a deceleration request signal to the ECM and MG ECU.

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

        • The MG ECU decreases the motive force of MG2 upon receiving this signal in order to cause the vehicle to decelerate.

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

          B00209OE01

        • If the driving support ECU assembly determines that further deceleration is necessary, it transmits a brake request signal to the hybrid vehicle control ECU. Upon receiving this signal, the hybrid vehicle control ECU transmits a brake request signal to the skid control ECU. The skid control ECU then controls the brake booster assembly 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 signal, in order to inform anyone who might be following the vehicle.

          B00208FE01

        • If the vehicle is not decelerating adequately, the driving support ECU assembly sounds a PCS buzzer (skid control buzzer) to prompt the driver to apply the brakes.

          B00208TE01

      2. Follow-up Control Function


        • After effecting deceleration control, the driving support ECU assembly transmits a request signal to the hybrid vehicle control ECU so that the vehicle can follow the preceding vehicle while maintaining the proper vehicle-to-vehicle distance in accordance with the vehicle speed.

        • The ECM regulates the throttle upon receiving this signal in order to effect follow-up control. Upon receiving this signal, the hybrid vehicle control ECU transmits a deceleration request signal to the ECM and MG ECU.

        • The MG ECU regulates the motive force of MG2 upon receiving this signal in order to effect 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.

          B00209YE01

      3. Acceleration Control Function


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

        • The ECM regulates the throttle in order to perform acceleration control.

        • The MG ECU regulates the motive force of MG2 in order to perform acceleration control.

          B00207XE01

      4. Automatic Cancel Control


        • When any of the conditions listed below occur while the vehicle is in cruise control, the cruise control is canceled. Then, the following warnings appear for the driver.

          Constant Speed Control Mode
          Description of Malfunction Warning
          Multi-information Display Master Warning Light Buzzer Cruise Control Indicator Light

          If either of the conditions listed below occur, the hybrid vehicle control ECU clears the set vehicle speed and cancels the cruise control.


          • Stop light switch open or short circuit

          Cruise control 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 -

          If the condition listed below occurs, the hybrid vehicle control ECU clears the set vehicle speed and cancels speed control by the cruise control system.


          • Malfunction in the hybrid system

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

          		 - - - -

          If the condition listed below occurs, the hybrid vehicle control ECU 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.

          		 - - - Illuminates

          If the condition listed below occurs, the hybrid vehicle control ECU cancels speed control by 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]).

          		 - - - Illuminates

        • Vehicle-to-vehicle Distance Control Mode
          Description of Malfunction Warning
          Multi-information Display Master Warning Light Buzzer Cruise Control Indicator Light

          If any of the conditions listed below occur, the hybrid vehicle control ECU clears the set vehicle speed and cancels speed control by the cruise control system.


          • Stop light switch open or short circuit

          Cruise control is disabled until the condition is 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 -

          If any of the conditions listed below occur, the hybrid vehicle control ECU clears the set vehicle speed and cancels speed control by 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

          Cruise control is disabled until the power switch is turned on (IG) again.

          		 Cruise Control Malfunction Visit Your Dealer Illuminates Sounds Once -

          If the condition listed below occurs, the hybrid vehicle control ECU clears the set vehicle speed and cancels speed control by the cruise control system.


          • Malfunction in the hybrid system

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

          		 - - - -

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


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

          Cruise control is disabled until the condition is 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 -

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


          • The measurement becomes extremely unstable due to poor weather conditions

          • When the radar cruise control system temporarily cannot use the brake system.

          • The beam axis of the millimeter wave radar sensor assembly is being aligned.

          • Forward recognition camera temporarily not available

          • A malfunction in the forward recognition camera

          Cruise control is disabled until the condition is 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 -

          If the condition listed below occurs, the hybrid vehicle control ECU cancels speed control by 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])

          		 - - Sounds Twice Illuminates

  4. DIAGNOSIS


    1. If a malfunction occurs in the dynamic radar cruise control system during cruise control operation, the hybrid vehicle control ECU cancels cruise control operation, illuminates the master warning light and turns off the cruise control indicator light (constant speed control mode) or radar cruise control indicator light (vehicle-to-vehicle distance control mode), and cruise control SET indicator light. Also, "Cruise Control Malfunction Visit Your Dealer" is displayed on the multi-information display to inform the driver of a malfunction. At the same 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.