DYNAMIC RADAR CRUISE CONTROL SYSTEM


  1. General


    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

      • C: Vehicle-to-vehicle Distance Control Mode (Models with Full-speed Range Following Function)

      Control Outline Mode
      A B C
      Constant Speed Control Gasoline Engine The ECM 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. If the actual vehicle speed is lower than the set speed, it uses the throttle control motor to increase the throttle opening. ○ ○ ○
      Diesel Engine The ECM compares the actual vehicle speed and the set speed. If the vehicle speed is higher than the set speed, the ECM decreases the fuel injection volume by regulating the 8 injectors. If the actual vehicle speed is lower than the set speed, the ECM increases the fuel injection volume by regulating the 8 injectors.
      In constant speed control mode, constant speed control is performed by the ECM in the same way as conventional cruise control. ○ - -
      In vehicle-to-vehicle distance control mode, constant speed control is performed by the millimeter wave radar sensor assembly, forward recognition camera and driving support ECU assembly. - ○ ○
      Deceleration Control Gasoline Engine Effects 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. - ○ ○
      Diesel Engine Effects fuel injection volume control and brake control in order to decelerate the vehicle so that the vehicle-to-vehicle distance between the 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 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 switch or depress the accelerator pedal), and resumes follow-up control after the vehicle is started. - - ○
      Set Control

      When the following conditions are met, and the cruise control switch is pressed to the -/SET side and released, the ECM 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 or the shift lever is in S with 4th, 5th, 6th, 7th*1 or 8th*1 shift range selected.

      		 ○ ○ ○
      The vehicle is traveling at a speed within the range of approximately 50 km/h to 200km/h (30 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). - ○ -
      The vehicle is traveling at a speed within the range of approximately 0 km/h to 180 km/h (0 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 Switch Control While the cruise control 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 will remain at the speed that the vehicle is traveling at when the COAST switch is released.

      		 - ○ ○
      Tap-down Control When the cruise control 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 km/h (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 or 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 1 km/h or 1 mph each time the switch is moved.*2

      • The vehicle will decelerate in increments of approximately 5 km/h or 5 mph each time the switch is moved.*3

      		 - ○ ○
      Accelerator Control When the cruise control 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.

      		 - ○ ○
      Resume Control When the vehicle speed is above the low speed limit, the cruise control system resumes operation (when the cruise control switch is subsequently moved to the +RES side) to reach the vehicle speed that was set at the time the driver canceled cruise control. Even if the vehicle speed dropped below the low speed limit, the set speed can be resumed after the vehicle speed increases above the low speed limit. Also, If the vehicle speed memory is deleted, the return control cannot be performed. ○ ○ ○
      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 switch to the +RES direction. - ○ ○
      Tap-up Control When the cruise control 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: ○ ○ ○

      • The vehicle will accelerate in increments of approximately 1 km/h (1 mph) for each time the switch was 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 1 km/h or 1 mph for each time the switch is moved.*2

      • The vehicle will accelerate in increments of approximately 5 km/h or 5 mph for each time the switch is moved.*3

      		 - ○ ○
      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, the transmission will shift up after a certain period of time. When the transmission shifts down during the accelerator control or the resume control, the transmission will shift up after the accelerator control or the resume control ends. ○ ○ ○
      Manual Cancel Control

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


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

      • When 1st, 2nd or 3rd shift range is selected manually while in S.

      • When 1st, 2nd or 3rd range is selected in D position by transmission shift switch assembly.*4

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

      • CANCEL switch on signal sent to the ECM (cruise control switch is moved to CANCEL side).

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

      • Parking brake is applied (only during vehicle-to-vehicle distance control mode).

      		 ○ ○ ○
      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. ○ ○ ○
      Other Cancel Control

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

      • VSC operation.

      • When the VSC or TRAC system is turned off by pressing the VSC OFF switch.

      		 ○ ○ ○
      Mode Switching Control

      The following operations switch modes:


      • Turning on the ON-OFF / Mode button launches the cruise control system in vehicle-to-vehicle distance control mode.

      • Keep pressing the ON-OFF / Mode button for 1.5 seconds or more while the cruise control system is deactivated switches the system to constant speed control mode.*5

      		 - ○ ○
      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. ○ ○ ○

      *1: Models with gasoline engine.

      *2: Except models for Europe.

      *3: Models for Europe.

      *4: Models with shift paddle switch.

      *5: Switching to constant speed control mode is only possible when operated while the cruise control system is deactivated.

      Tech Tips

      ○: Available

      -: Not Available

  2. Constant Speed Control


    1. General


      1. In the constant speed control mode, the constant speed control is performed by the ECM.

      2. In the vehicle-to-vehicle distance control mode, the constant speed control is performed by the millimeter wave radar sensor and forward recognition camera and driving support ECU.

    2. Constant Speed Control in Vehicle-to-vehicle Distance Control Mode


      1. The millimeter wave radar sensor assembly and forward recognition camera transmits the information about the vehicle ahead to the driving support ECU assembly and also transmits a millimeter wave radar sensor assembly operation signal to the ECM via the driving support ECU assembly.

      2. On models with gasoline engine, the ECM compares the set speed and the actual vehicle speed, and effects constant speed control by regulating the throttle control in order to attain the set speed.

      3. On models with diesel engine, the ECM compares the set speed and the actual vehicle speed, and effects constant speed control by regulating the fuel injection volume in order to attain the set speed.

        A01W7G8E01

  3. Deceleration Control


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

    2. On models with gasoline engine, the ECM closes the throttle valve upon receiving this signal in order to cause the vehicle to decelerate.

    3. On models with diesel engine, the ECM decreases the fuel injection volume upon receiving this signal by regulating the 8 injectors in order to cause the vehicle to decelerate.

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

      A01W7ODE01

    5. If the driving support ECU 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.

    6. 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, order to warn any vehicles behind.

      A01W73GE01

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

      A01W72XE01

  4. Follow-up Control


    1. After performing deceleration control, the driving support ECU 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.

    2. On models with gasoline engine, the ECM regulates the throttle upon receiving this signal in order to perform follow-up control.

    3. On models with diesel engine, the ECM regulates the fuel injection volume upon receiving this signal in order to perform follow-up control.

    4. 3 stages (long, middle, and short) of vehicle-to-vehicle distance can be selected by operating the distance control switch.

      A01W7VCE01

  5. Acceleration Control


    1. 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 ECM in order to attain the set vehicle speed.

    2. On models with gasoline engine, the ECM regulates the throttle upon receiving this signal in order to perform acceleration control.

    3. On models with diesel engine, the ECM regulates the fuel injection volume upon receiving this signal in order to perform acceleration control.

      A01W7PGE01

  6. Stop Control (Models with Full-speed Range Following Function)


    1. The driving support ECU assembly detects if the vehicle ahead stops through the signals from the millimeter wave radar sensor assembly and calculates the motive force required to stop the driver's own vehicle while maintaining the appropriate vehicle-to-vehicle distance. The ECU than transmits the motive force request signals to the ECM and the skid control ECU. Upon receiving this signal, these ECUs control the motive force and stop vehicle.

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

    3. The distance between the driver's own vehicle when the vehicles are stopped is set to approximately 5 m to 7 m (16.4 ft. to 22.3 ft.) regardless of the vehicle-to-vehicle distance preset by using the distance control switch.

      A01W7U1E01

  7. Stop Retention Control (Models with Full-speed Range Following Function)


    1. 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 function and keeps the vehicle stopped

      A01W7MIE01

  8. Start Control (Models with Full-speed Range Following Function)


    1. When the driving support ECU assembly detects that the vehicle ahead starts moving again from the millimeter wave radar sensor assembly signal, it displays the messages "Operate Cruise Lever or Accelerator Pedal to Resume" on the multi-information display to urge the driver to perform the start-off operation. (to push the cruise control switch to the +RES side or depress the accelerator pedal).

    2. Upon receiving the start-off operation signal generated by pushing the cruise control switch assembly to the +RES side or by depressing the accelerator pedal, the driving support ECU assembly transmits a motive force request signal to the ECM. Upon receiving the signal, the ECM controls the motive force, starts the vehicle and resumes follow-up control.

      A01W753E01

  9. Automatic Cancel Control


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

      Constant Speed Control Mode
      Situation Warning
      Multi-information Display A01W784 Buzzer in the Combination Meter Assembly

      If either of 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.

      Cruise control is prohibited until the normal operating condition is met or the cruise control system is turned off and back on again using the ON-OFF / Mode button on the cruise control main switch.

      		 Cruise Control Malfunction Visit Your Dealer Illuminates Sounds once

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


      • Stop light switch assembly input signal is abnormal.

      • Cancel circuit malfunction.

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

      		 Cruise Control Malfunction Visit Your Dealer Illuminates Sounds once

      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)].

      		 - - -

      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.

      		 - - -

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


      • A malfunction in the ETCS-i.*1

      • A malfunction in the ECD system.*2

      Cruise control is prohibited until the normal operating conditions are met or the cruise control system is turned off and back on again using the ON-OFF / Mode button on the cruise control main switch.

      		 - - -

      *1: Models with gasoline engine

      *2: Models with diesel engine

      Vehicle-to-vehicle Distance Control Mode
      Situation Warning
      Multi-information Display A01W784 Buzzer in the Combination Meter Assembly

      If either of 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.

      Cruise control is prohibited until the normal operating conditions are met or the cruise control system is turned off and back on again using the ON-OFF / Mode button on the cruise control main switch.

      		 Cruise Control Malfunction Visit Your Dealer Illuminates Sounds once

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


      • Stop light switch assembly input signal is abnormal.

      • Cancel circuit malfunction.

      • 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.

      • Malfunction in the electric parking brake system.*3

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

      		 Cruise Control Malfunction Visit Your Dealer Illuminates Sounds once

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


      • A malfunction in the ETCS-i.*1

      • A malfunction in the ECD system.*2

      The 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 / Mode button on the cruise control main switch.

      		 - - -

      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.

      Cruise control is prohibited until the normal operating conditions are met or the cruise control system is turned off and back on again using the ON-OFF / Mode button on the cruise control main switch.

      		 Radar Cruise Control Unavailable Clean Radar Sensor Illuminates Sounds once

      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.

      • 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 prohibited until the normal operating conditions are met or the cruise control system is turned off and back on again using the ON-OFF / Mode button on the cruise control main switch.

      		 Radar Cruise Control Unavailable Illuminates Sounds once

      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.*3


      • Stop light switch assembly input signal is abnormal.

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

      • Malfunction in the millimeter wave radar sensor assembly.

      • Beam axis of millimeter wave radar sensor assembly misaligned.

      • The electric parking brake system is malfunctioning.

      • Problem with cruise control switch cancel circuit.

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

      • The forward recognition camera is temporarily unavailable.

      • A system check is being performed after the engine has started.

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

      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.*3


      • The driver seat belt is unfastened

      • The driver door is opened.

      • The engine hood or back 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 Depress Brake to Resume Driving - -

      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)].

      		 - - Sounds twice

      *1: Models with gasoline engine

      *2: Models with diesel engine

      *3: Models with full-speed range following function

  10. Diagnosis


    1. If a malfunction occurs in the dynamic radar cruise control system, the ECM actuates the automatic cancel control and turns off the cruise control indicator light or the radar cruise control indicator light. Then, the multi-information display in the combination meter displays "Cruise Control Malfunction Visit Your Dealer" warning message to inform the driver of a malfunction during cruise control. At this time, the ECM memorizes the malfunction in the form of 5-digit Diagnostic Trouble Codes (DTCs).


      • The 5-digit DTCs can be read by connecting a Global TechStream (GTS) to the DLC3. For details, refer to Repair Manual.