FUNCTION OF MAIN COMPONENTS
The main components in the dynamic radar cruise control system have the following functions:
| Component | Function | |
|---|---|---|
| Millimeter Wave Radar Sensor Assembly | Radiates millimeter radar waves forward, uses the reflected waves to detect the presence of a vehicle traveling ahead, the vehicle-to-vehicle distance, and the relative speed, and then transmits this information to the driving support ECU assembly. | |
| Forward Recognition Camera | Detects lane markers and objects on the road ahead using the image captured by the monocular camera and sends the information to the driving support ECU assembly. | |
| Camera Heater (Forward Recognition Hood with Heater Sub-assembly) | The camera heater is heated according to signals from the forward recognition camera. | |
| Driving Support ECU Assembly |
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| PCS Buzzer (Skid Control Buzzer Assembly) | Sounds upon receiving a signal from the driving support ECU assembly and alerts the driver that the distance between vehicles is short. | |
| Cruise Control Switch | ON-OFF Button |
|
| CANCEL Switch | A cancel signal is output to the hybrid vehicle control ECU 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 hybrid vehicle control ECU when this switch is operated. | |
| -SET Switch | The deceleration function and vehicle speed setting resume 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 distance control switch to select the vehicle-to-vehicle distance in 3 levels: long, middle, and short. |
| Hybrid Vehicle Control ECU |
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| Inverter with Converter Assembly | MG ECU | Built into the inverter with converter assembly. Controls the motive force of MG2 in accordance with signals from the hybrid vehicle control ECU. |
| Hybrid Vehicle Transaxle Assembly | MG2 | Generates motive force for the wheels. |
| ECM | Actuates the throttle control motor in accordance with the signals from the hybrid vehicle control ECU. | |
| Brake Booster with Master Cylinder Assembly | Skid Control ECU |
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| Combination Meter Sub-assembly | Cruise Control Indicator Light |
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| Cruise SET Indicator Light | Illuminates when the vehicle speed is set. | |
| Buzzer | If the driving support ECU assembly detects automatic cancel or warning signals while the vehicle is operating under cruise control, this buzzer sounds to inform the driver. | |
| Multi-information Display |
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| Throttle Body 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. | |
| Speed Sensor | Detects the wheel speed of each of the 4 wheels. | |
| Accelerator Pedal Sensor Assembly | Detects the accelerator pedal depression degree and outputs it to the hybrid vehicle control ECU. | |
| Stop Light Switch Assembly | Detects brake pedal depression and transmits its signal to the hybrid vehicle control ECU. | |
| Shift Lock Control Unit Assembly | Shift Lever Position Sensor | Detect the shift lever position and transmit signals to the hybrid vehicle control ECU. |
| Spiral Cable with Sensor Sub-assembly | Steering Sensor | Detects the angle and direction of steering and transmits signals to the driving support ECU assembly. |
| Airbag ECU Assembly | Yawrate Sensor | Detects the yawrate of the vehicle and transmits signals to the driving support ECU assembly. |
| Central Gateway ECU (Network Gateway ECU) | Gateway function of CAN communication. | |
FUNCTION
Function List
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 | Controls the motive force through the hybrid vehicle control ECU and skid control ECU assembly, and adjusts the vehicle speed to the set vehicle speed. | ○ | ○ |
| Deceleration Control | Performs engine, MG2 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 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 cruise control system has been turned on using the ON-OFF button on the cruise control switch, either of the relevant vehicle speed conditions shown below is met, and the cruise control switch is moved to the -SET side and released, the driving support ECU assembly stores the vehicle speed and maintains the vehicle constantly at that speed. | ○ | ○ |
| The vehicle is traveling at a speed within the range of approximately 40 km/h to 200 km/h (25 mph to 125 mph). | ○ | - | |
| The vehicle is being driven at an approximate speed of between 50 km/h to 180 km/h (30 mph to 110 mph). | - | ○ | |
| Low Speed Limit Control | The low speed limit is the lowest speed that cruise control can be operated at and it is designed to be approximately 40 km/h (25 mph). The cruise control system cannot be operated below that speed. If the vehicle speed drops below that speed while the cruise control system is set and working to maintain vehicle speed, speed control by the cruise control system will be canceled automatically. The set vehicle speed is kept in memory. | ○ | ○ |
| COAST Switch Control | When 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: | ○ | ○ |
|
○ | - | |
|
- | ○ | |
| 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: | ○ | ○ |
|
○ | - | |
|
- | ○ | |
| ACC Switch 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: | ○ | ○ |
|
○ | - | |
|
- | ○ | |
| 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: | ○ | ○ |
|
○ | - | |
|
- | ○ | |
| RES Switch Control | If 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. | ○ | ○ |
| 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 moving the cruise control switch to the +RES side. | - | ○ | |
| Manual Cancel Control | If any of the following signals are sent to the hybrid vehicle control ECU, cruise control speed control operation is canceled accordingly.
|
○ | ○ |
| Automatic Cancel Control | When an automatic cancel signal is sent to the hybrid vehicle control ECU, cruise control speed control operation is canceled. At this time, the type of warning sent to the driver and the control resumption condition vary according to the cancel signal. | ○ | ○ |
| Mode Switching Control | The following operations switch modes:
|
○ | ○ |
| Other Cancel Conditions | If any of the following conditions occur during cruise control driving, speed control by the cruise control system is canceled.
|
○ | ○ |
| Diagnosis | If a malfunction occurs in the dynamic radar cruise control system during cruise control operation, the hybrid vehicle control ECU cancels cruise control and memorizes information related to the malfunction. | ○ | ○ |
*1: Models for Europe
*2: Except models for Europe
○: Available
-: Not Available
Constant Speed Control
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 hybrid vehicle control ECU via the driving support ECU assembly. The hybrid vehicle control ECU compares the set vehicle speed and the actual vehicle speed, and performs constant speed control by regulating the throttle in order to attain the set vehicle speed.
In vehicle-to-vehicle distance control mode, the driving support ECU assembly performs deceleration control, follow-up control or acceleration control based on the information about the vehicle ahead transmitted from the millimeter wave radar sensor assembly and forward recognition camera.
Vehicle-to-vehicle Distance Control Mode
In vehicle-to-vehicle distance control mode, the hybrid vehicle control ECU performs deceleration control function, follow-up control and acceleration control function based on the information about the vehicle ahead transmitted from the driving support ECU assembly, millimeter wave radar sensor assembly and forward recognition camera.
Deceleration Control
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 hybrid vehicle control ECU. Upon receiving this signal, the hybrid vehicle control ECU performs engine, MG2 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 driving support ECU assembly determines that further deceleration is necessary, it transmits a brake request signal to the skid control ECU. Upon receiving this signal, the skid control ECU then activates the brake actuator to apply the brakes.
At this time, if the deceleration rate is higher than a predetermined value, the skid control ECU outputs a stop light illumination request signal to the stop light control relay in order to inform anyone who might be following the vehicle.
If the vehicle is not decelerating adequately, the skid control ECU sounds the PCS buzzer (skid control buzzer assembly) based on a request signal from the driving support ECU assembly. The buzzer is sounded to urge the driver to depress the brake pedal.
Follow-up Control
After performing deceleration control, the driving support ECU assembly transmits request signals to the hybrid vehicle control ECU 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 vehicle speed. Upon receiving these signals, these ECUs control the motive force in order to perform follow-up control.
3 levels (long, middle, and short) of vehicle-to-vehicle distance can be selected by operating the vehicle-to-vehicle distance control switch.
Acceleration Control
If the driving support ECU assembly detects that either the vehicle ahead or own vehicle has changed lanes, 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 controls the motive force of the engine and MG2 in order to perform acceleration control.
Automatic Cancel Control
If any of the conditions listed below occur while the vehicle is being driven using cruise control, speed control by the cruise control system will be canceled. Then, the following warning items will appear for the driver.
| Situation | Warning | ||
|---|---|---|---|
| Multi-information Display | |
Buzzer in the combination meter sub-assembly | |
| 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
Speed control by 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 switch. |
CHECK CRUISE CONTROL SYSTEM | Illuminates | Sounds |
| 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.
Speed control by the cruise control system is disabled until the conditions are remedied or the cruise control system is turned off and back on again using the ON-OFF button on the cruise control switch. |
- | Illuminates | - |
| 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.
|
- | Does not illuminate | - |
| 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.
|
- | Does not illuminate | - |
| If either of the conditions listed below occurs, the hybrid vehicle control ECU cancels speed control by the cruise control system.
|
- | Does not illuminate | - |
| Situation | Warning | ||
|---|---|---|---|
| Multi-information Display | |
Buzzer in the combination meter sub-assembly | |
| 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.
Speed control by 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 switch. |
CHECK CRUISE CONTROL SYSTEM | Illuminates | Sounds |
| 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.
Speed control by the cruise control system is disabled until the power switch is turned on (IG) again. |
CHECK CRUISE CONTROL SYSTEM | Illuminates | Sounds |
| 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.
Speed control by the cruise control system 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 switch. |
- | 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.
Speed control by the cruise control system is prohibited 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 switch. |
CLEAN RADAR SENSOR | Illuminates | Sounds |
| 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.
Speed control by the cruise control system is prohibited 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 switch. |
CRUISE CONTROL NOT AVAILABLE | Illuminates | Sounds |
| 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.
|
- | Does not illuminate | Sounds Twice |
| If either of the conditions listed below occurs, the hybrid vehicle control ECU cancels speed control by the cruise control system.
|
- | Does not illuminate | - |
CONSTRUCTION
Cruise Control Switch
The cruise control switch consists of the ON-OFF button, and the +RES, -SET and CANCEL switches. The ON-OFF button, +RES, -SET and CANCEL switches are operated by moving the lever in the 4 directions indicated.
When the cruise control system is turned on using the main switch (ON-OFF button), the system starts in vehicle-to-vehicle distance control mode. When the main switch is pushed and held for 1.5 seconds or more from the cruise control system off, The system changes to constant control mode.
| *1 | Steering Pad Switch Assembly
|
*2 | Cruise Control Switch |
| *a | ON-OFF Button | *b | +RES Switch |
| *c | -SET Switch | *d | CANCEL 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 distance control switch is pressed; long → middle → short → long.
If the power 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 (130 ft.) |
| Short | Approximately 30 m (100 ft.) |
Tech Tips
*: While driving at a speed of 80 km/h (50 mph).
Millimeter Wave Radar Sensor
The millimeter wave radar sensor assembly emits electrical waves in the millimeter waveband towards the front of the vehicle. When a preceding vehicle is present, the sensor receives electrical waves reflected off of the rear surface of the preceding vehicle. The system determines whether there is a preceding vehicle in the same lane and calculates the distance to the preceding vehicle and relative vehicle speed according to the change in frequency of the received electrical waves and using an electronic scan. This calculated data is then output to the driving support ECU assembly. For details about the millimeter wave radar sensor assembly, refer to the pre-collision system.
Forward Recognition Camera
The forward recognition camera captures images of the front with the monocular camera that is equipped. By performing image processing on the captured images, the size of the preceding vehicle and lane marker recognition of the road are possible; in addition, improvements were designed for things such as recognition precision for preceding vehicles, road judgment and detection of vehicles cutting into the lane. For details about the forward recognition camera, refer to the lane departure alert system (w/ steering control).
OPERATION
Combination Meter Sub-assembly
The combination meter sub-assembly has a master warning light, cruise control indicator light (constant speed control mode), cruise control indicator light (vehicle-to-vehicle distance control mode), cruise SET indicator light, buzzer, and multi-information display to provide warnings and messages regarding the dynamic radar cruise control system.
The multi-information display displays the set vehicle speed, vehicle ahead mark, and warning message.
Figure 1. LHD Models
| *a | Cruise Control Indicator Light (Constant Speed Control Mode) | *b | Cruise SET Indicator Light |
| *c | Cruise Control Indicator Light (Vehicle-to-vehicle Distance Control Mode) | *d | Master Warning Light |
| *e | Multi-information Display | - | - |
Figure 2. RHD Models
| *a | Cruise Control Indicator Light (Constant Speed Control Mode) | *b | Cruise SET Indicator Light |
| *c | Cruise Control Indicator Light (Vehicle-to-vehicle Distance Control Mode) | *d | Master Warning Light |
| *e | Multi-information Display | - | - |
| Condition | Multi-information Display*1, *2 | |
|
Buzzer |
|---|---|---|---|---|
| Being Controlled | |
Illuminates | Does not illuminate | - |
| System Check | CHECK CRUISE CONTROL SYSTEM | Does not illuminate | Illuminates | Buzzer in the combination meter sub-assembly sounds |
*1: While driving at a set speed of 100 km/h (62 mph).
*2: These illustrations are examples.
| Condition | Multi-information Display*1, *2 | |
|
Buzzer | ||
|---|---|---|---|---|---|---|
| Set Standby | RADAR READY | Illuminates | Does not illuminate | - | ||
| Set Standby (Short) | |
Illuminates | Does not illuminate | - | ||
| Under Constant Speed Control (No Vehicle Ahead, Middle) | |
Illuminates | Does not illuminate | - | ||
| Under Follow-up Control (Vehicle Ahead, Long | |
Illuminates | Does not illuminate | - | ||
| Deceleration Control/Vehicle Approach Warning (Vehicle Ahead, Long) |
|
Illuminates | Does not illuminate | PCS Buzzer (Skid Control Buzzer Assembly) sounds continuously | ||
| Blinks | ||||||
| Millimeter Wave Radar Sensor Assembly or the Emblem are Dirty. | CLEAN RADAR SENSOR | Does not illuminate | Illuminates | Buzzer in the combination meter sub-assembly sounds | ||
|
CRUISE CONTROL NOT AVAILABLE | Does not illuminate | Illuminates | Buzzer in the combination meter sub-assembly sounds | ||
| System Check | CHECK CRUISE CONTROL SYSTEM | Does not illuminate | Illuminates | Buzzer in the combination meter sub-assembly sounds |
*1: While driving at a set speed of 100km/h (62 mph).
*2: These illustrations are examples.
DIAGNOSIS
If a malfunction occurs in the dynamic radar cruise control system during cruise control operation, the hybrid vehicle control ECU and driving support ECU assembly cancels the cruise control operation, illuminates the master warning light, sounds a buzzer in the combination meter sub-assembly, and displays a warning message on the multi-information display to inform the driver of the malfunction. At this time, the malfunction is stored in memory as a Diagnostic Trouble Code (DTC).
The DTCs can be read when a Global TechStream (GTS) is connected to the DLC3. For details, refer to the Repair Manual.