FUNCTION OF MAIN COMPONENTS
The main components in the dynamic radar cruise control system have the following functions:
| Component | Function | |
|---|---|---|
| ECM |
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| Driving Support ECU Assembly |
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| 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, and then sends this information to the driving support ECU assembly. | |
| Camera Sensor (Forward Recognition Camera) |
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| Camera Heater (Forward Recognition Hood with Heater Sub-assembly) | The camera heater is heated according to signals from the camera sensor. | |
| 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 sends it to the ECM. | |
| Steering Pad Switch Assembly | Cruise Control Main Switch |
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| -SET Switch | The deceleration function and vehicle speed setting resume signals are sent to the ECM. | |
| +RES Switch | The acceleration function and resuming of a preset speed can be performed by operating this switch. A signal is sent to the ECM. | |
| CANCEL Switch | A cancel signal is sent to the ECM. | |
| Vehicle-to-vehicle Distance Control Switch | While the dynamic radar cruise control 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. | |
| Stop Light Switch Assembly | Detects brake pedal depression and sends its signal to the ECM. | |
| Combination Meter Assembly | Cruise Control Indicator (Constant Speed Control Mode) |
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| Cruise Control Indicator (Vehicle-to-vehicle Distance Control Mode) |
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| Cruise Control SET Indicator | Illuminates when the vehicle speed is set. | |
| Meter Buzzer |
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| Multi-information Display | During cruise control operation, the multi-information display receives signals from the ECM in order to display the system conditions. | |
| Master Warning Indicator | Comes on when there is a malfunction in the dynamic radar cruise control system. | |
| Steering Sensor | Detects the angle and direction of steering and sends signals to the ECM. | |
| Yawrate Sensor | Detects the yaw rate of the vehicle and sends signals to the ECM. | |
| Brake Actuator Assembly
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| Accelerator Pedal Sensor Assembly | Detects the accelerator pedal depression degree and sends it to the ECM. | |
| Parking Brake ECU Assembly*1 | Controls the parking brake actuator assembly based on operation signals from the electric parking brake switch assembly and parking brake request signals from ECUs. | |
| Electric Parking Brake Switch Assembly*1 | Sends a parking brake application signal to the parking brake ECU assembly. | |
| Parking Brake Actuator Assembly*1 | Operates the parking brake actuator assembly according to signals from the parking brake ECU assembly. | |
| Paddle Shift Switch (Transmission Shift Switch Assembly) | While the vehicle is being driven in D mode, this switch sends a signal to the ECM when the switch is pulled to "+" or "-". | |
| Airbag ECU Assembly | Sends vehicle collision signals to the driving support ECU Assembly. | |
| Headup Display (Meter Mirror Sub-assembly)*2 | The headup display receives signals from the ECM in order to display the system conditions. | |
| Central Gateway ECU (Network Gateway ECU) | Transmits the signal between the CAN communication buses. | |
| DLC3 | The Global TechStream (GTS) can be connected to read the Diagnostic Trouble Codes (DTCs) of malfunctions. | |
*1: Models with full-speed range following function
*2: Models with headup display
SYSTEM CONTROL
The driving support ECU assembly, millimeter wave radar sensor assembly, camera sensor and ECM control the dynamic radar cruise control system.
The combination meter assembly and headup display* inform the driver of the control conditions.
*: Models with headup display
For vehicles with the dynamic radar cruise control system, constant speed control mode is controlled by the ECM.
Vehicle-to-vehicle distance control mode is controlled by the millimeter wave radar sensor assembly, camera sensor and driving support ECU assembly. Thus, signals are sent to the actuators and the ECU while exchanging data as indicated below.
FUNCTION
Control of Dynamic Radar Cruise Control System Varies Depending on 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)
| Function | Outline | Mode | ||
|---|---|---|---|---|
| A | B | C | ||
| 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 accelerates the vehicle by adjusting the respective motive forces. | ○ | ○ | ○ |
| 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 is maintained at 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. The actual distance maintained for each distance level (long, medium and short) varies 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 operation (to operate the +RES switch on the steering pad switch assembly 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 main 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 traveling at a speed of approximately 50 km/h or more (30 mph or more). | ○ | ○ | ○ | |
| 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 dynamic radar cruise control system cannot be set below that speed. If the vehicle speed drops below that speed while driving using cruise control, speed control by the dynamic radar cruise control system 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: | ○ | ○ | ○ |
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○ | - | - | |
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- | ○ | ○ | |
| 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: | ○ | ○ | ○ |
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○ | - | - | |
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- | ○ | ○ | |
| 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: | ○ | ○ | ○ |
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○ | - | - | |
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- | ○ | ○ | |
| 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: | ○ | ○ | ○ |
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○ | - | - | |
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- | ○ | ○ | |
| 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 C 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 while stop retention control is being performed and the message that urges the driver to perform the start operation has been displayed, when the +RES switch on steering pad switch assembly is pushed, follow-up control is resumed and the vehicle can be accelerated up to the set speed. | - | - | ○ | |
| 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 any of the following signals are sent to the ECM, the cruise control is canceled accordingly:
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○ | ○ | ○ |
| 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:
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○ | ○ | ○ |
| Other Control Cancellation Conditions | If any of the following conditions occur during cruise control driving, speed control by the dynamic radar cruise control system is canceled. However, the set speed remains in the memory:
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○ | ○ | ○ |
*1: Except models for Europe
*2: Models for Europe
Tech Tips
○: Available
-: Not available
Constant Speed Control Mode
The ECM compares the set vehicle speed and the actual vehicle speed, and performs constant speed control in order to attain the set vehicle speed.
Vehicle-to-vehicle Distance Control Mode
In vehicle-to-vehicle distance control mode, the ECM performs the constant speed control function, 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 sent from the driving support ECU assembly, millimeter wave radar sensor assembly and camera sensor.
*: Models with full-speed range following function
Constant Speed Control Function
The millimeter wave radar sensor assembly and camera sensor send information about the vehicle ahead to the driving support ECU assembly and also send a millimeter wave radar sensor assembly operation signal to the ECM via the driving support ECU assembly. The ECM compares the set vehicle speed and the actual vehicle speed, and performs constant speed control in order to attain the set vehicle speed.
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 camera sensor, and sends a deceleration request signal to the ECM. Upon receiving this signal, the ECM performs throttle control and brake control 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.
If the ECM determines that further deceleration is necessary, it sends a brake request signal to the skid control ECU. Upon receiving this signal, the skid control ECU then activates the brake actuator assembly to apply the brakes.
At this time, if the deceleration rate is higher than a predetermined value, the skid control ECU sends a stop light illumination request signal in order to inform anyone who might be following the vehicle.
If the vehicle is not decelerating adequately, the ECM sounds the meter buzzer. The buzzer is sounded to urge the driver to depress the brake pedal.
Follow-up Control Function
After performing deceleration control, the driving support ECU assembly sends request signals to the ECM so that the vehicle can follow the vehicle ahead while maintaining the proper vehicle-to-vehicle distance. The actual distance maintained for each distance level (long, middle and short) varies in accordance with the vehicle speed. Upon receiving these signals, these ECUs control the motive force 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.
Acceleration Control Function
If the driving support ECU assembly detects that either the vehicle ahead or the driver's own vehicle has changed lanes, a request signal is sent to the ECM in order to attain the set vehicle speed. Upon receiving this signal, the ECM controls the motive force in order to perform acceleration control.
Stop Control Function (Models with Full-speed Range Following Function)
The driving support ECU assembly detects if the vehicle ahead stops through signals from the millimeter wave radar sensor assembly and camera sensor, and calculates the motive force required to stop the driver's own vehicle while maintaining the appropriate vehicle-to-vehicle distance. The ECU then sends a motive force request signal to the ECM. Upon receiving this signal, the ECM controls the motive force and stops the vehicle.
At this time, if the deceleration rate is higher than a predetermined value, the skid control ECU sends 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 3 m to 5 m (10 ft. to 16 ft.) regardless of the vehicle-to-vehicle distance preset by using the vehicle-to-vehicle distance control switch.
Stop Retention Control Function (Models with Full-speed Range Following Function)
After the vehicle has stopped under stop control, the ECM sends 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.
Tech Tips
If the vehicle ahead starts off within approximately 3 seconds after own vehicle stops, follow-up cruising will be resumed.
Start Control Function (Models with Full-speed Range Following Function)
When the driving support ECU assembly detects that the vehicle ahead starts moving again from the millimeter wave radar sensor assembly and camera sensor signal, it displays the messages on the multi-information display and headup display* to urge the driver to perform the start operation (to push the +RES switch on the steering pad switch assembly or to depress the accelerator pedal).
*: Models with headup display
Upon receiving the start operation signal generated by pushing the +RES switch on the steering pad switch assembly or by depressing the accelerator pedal, the driving support ECU assembly sends 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.
Tech Tips
Pressing the +RES switch while the vehicle ahead stops will resume follow-up cruising if the vehicle ahead starts off within approximately 3 seconds after the switch is pressed.
Automatic Cancel Control
If any of the conditions listed below occur while the vehicle is being driven using cruise control, speed control by the dynamic radar cruise control system will be canceled. Then, the following warning items will appear for the driver.
| Description of Malfunction | Multi-information Display | Master Warning Indicator |
|---|---|---|
| If the condition listed below occurs, the ECM clears the set vehicle speed and cancels speed control by the dynamic radar cruise control system.
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 main switch on the steering pad switch assembly. |
Cruise Control Malfunction Visit Your Dealer |
Illuminates |
| If the condition listed below occurs, the ECM clears the set vehicle speed and cancels speed control by the dynamic radar cruise 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 main switch on the steering pad switch assembly. |
- | - |
| If the condition listed below occurs, the ECM clears the set vehicle speed and cancels speed control by the dynamic radar cruise control system.
|
- | - |
| If the condition listed below occurs, the ECM cancels speed control by the dynamic radar cruise control system while retaining the set vehicle speed in its memory.
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- | - |
| If either of the conditions listed below occurs, the ECM clears the set vehicle speed and cancels speed control by the dynamic radar cruise control system.
|
- | - |
| Description of Malfunction | Multi-information Display | Master Warning Indicator |
|---|---|---|
| If the condition listed below occurs, the ECM clears the set vehicle speed and cancels speed control by the dynamic radar cruise control system.
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 main switch on the steering pad switch assembly. |
Cruise Control Malfunction Visit Your Dealer |
Illuminates |
| If either of the conditions listed below occurs, the ECM clears the set vehicle speed and cancels speed control by the dynamic radar cruise control system.
Speed control by the dynamic radar cruise control system is disabled until the engine switch is turned on (IG) again. |
Cruise Control Malfunction Visit Your Dealer |
Illuminates |
| If the condition listed below occurs, the ECM clears the set vehicle speed and cancels speed control by the dynamic radar cruise 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 main switch on the steering pad switch assembly. |
- | - |
| If the condition listed below occurs, the ECM cancels speed control by the dynamic radar cruise control system while retaining the set vehicle speed in its memory.
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 main switch on the steering pad switch assembly. |
Radar Cruise Control Unavailable Clean Sensor |
Illuminates |
| If either of the conditions listed below occurs, the ECM cancels speed control by the dynamic radar cruise control system while retaining the set vehicle speed in its memory.
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 main switch on the steering pad switch assembly. |
Radar Cruise Control Unavailable |
Illuminates |
| If either of the conditions listed below occurs, the ECM cancels speed control by the dynamic radar cruise control system while retaining the set vehicle speed in its memory.*2
|
Cruise Control Fault Press Brake to Deactivate Visit Your Dealer |
Illuminates |
| If either of the conditions listed below occurs, the ECM clears the set vehicle speed and cancels speed control by the dynamic radar cruise control system.
|
- | - |
| If either of the conditions listed below occurs, the ECM cancels speed control by the dynamic radar cruise control system.*2
|
Radar Cruise Control Unavailable Depress Brake to Resume Driving |
- |
| If either of the conditions listed below occurs, the ECM cancels speed control by the dynamic radar cruise control system.*2
|
- | - |
| If the condition listed below occurs, the ECM cancels speed control by the dynamic radar cruise control system while retaining the set vehicle speed in its memory.
|
- | - |
Tech Tips
*1: Models with full-speed range following function
*2: During stop retention control (models with full-speed range following function)
Cruise Control Operation Switch
The operation switches of the dynamic radar cruise control system (cruise control main switch, -SET switch, +RES switch, CANCEL switch and vehicle-to-vehicle distance control switch) are positioned in the steering pad switch assembly.
| Component | Function |
|---|---|
| Cruise Control Main Switch |
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| +RES Switch | Performs accelerator control, tap-up control and resume control. |
| -SET Switch | Performs set control, coast control and tap-down control. |
| CANCEL Switch | Cancels control. |
| Vehicle-to-vehicle Distance Control Switch | Switches between the vehicle-to-vehicle distance settings. |
| *1 | Vehicle-to-vehicle Distance Control Switch | *2 | -SET Switch |
| *3 | CANCEL Switch | *4 | Cruise Control Main Switch |
| *5 | +RES Switch | - | - |
Vehicle-to-vehicle Distance Control Switch
While the vehicle is being driven in vehicle-to-vehicle distance control mode, the vehicle-to-vehicle distance setting can be changed as follows each time the vehicle-to-vehicle distance control switch is pressed; long → middle → short → long.
If the engine switch is turned off and back on (IG), the system will default to "long".
The vehicle-to-vehicle distance is as follows:
| Mode | Vehicle-to-vehicle Distance* |
|---|---|
| Long | Approximately 50 m (160 ft.) |
| Middle | Approximately 40 m (131 ft.) |
| Short | Approximately 30 m (98 ft.) |
Tech Tips
*: While driving at a speed of 80 km/h (50 mph).
DIAGNOSIS
In order to make system inspections easier to perform, a diagnosis function is used in consideration of serviceability. The DTCs of malfunctioning parts can be read by connecting the Global TechStream (GTS). Refer to the Repair Manual for details.