PRE-COLLISION SYSTEM DESCRIPTION
The pre-collision system uses the pre-collision warning control, pre-collision brake assist control and pre-collision braking control to help avoid a collision or reduce the impact if it determines that the possibility of a collision is high or a collision is unavoidable based on the position and relative speed of a preceding vehicle.
The operation of this system can be turned off and on using the setting screen of the multi-information display.
Tech Tips
When the pre-collision system is turned off, the PCS warning light in the combination meter assembly will illuminate.
PRE-COLLISION SYSTEM SENSOR DESCRIPTION
The millimeter wave radar sensor assembly and forward recognition camera detect the position and relative speed of preceding vehicles and pedestrians*. This information is sent to the driving support ECU to determine if the possibility of a collision is high or a collision is unavoidable.
Tech Tips
*: Depending on the vehicle destination and specifications, the pedestrian detection function may not be available.
FUNCTION OF MAIN COMPONENTS
| COMPONENTS | FUNCTION |
|---|---|
| Millimeter Wave Radar Sensor Assembly |
|
| Driving Support ECU Assembly |
|
| Forward Recognition Camera | Captures images of the area in front of the vehicle and processes them to detect preceding vehicles or pedestrians and sends information to the driving support ECU assembly. |
| Yaw Rate Sensor | Detects the yaw rate and acceleration of the vehicle and sends signals to the driving support ECU assembly. |
| Steering Sensor | Detects the steering angle and direction and sends signals to the driving support ECU assembly. |
| Vehicle Speed Sensor | Detects the wheel speed and sends signals to the skid control ECU. |
| Stop Light Switch Assembly | Detects the depression of the brake pedal and sends signals to the skid control ECU. |
| Stop Light Relay (Semiconductor Power Integration ECU) | Illuminates the stop lights based on the pre-collision braking control operation signal from the skid control ECU. |
| Steering Pad Switch Assembly |
|
| VSC OFF Switch | Disables the pre-collision brake assist control and pre-collision braking control if pressed and held. |
| Skid Control ECU Assembly |
|
| Combination Meter Assembly |
|
| Skid Control Buzzer | Sounds to warn the driver when the pre-collision warning control is operated. |
| Main Body ECU (Multiplex Network Body ECU) | Sends vehicle destination country information to the driving support ECU assembly. |
| Hybrid Vehicle Control ECU Assembly |
|
| Absorber Control ECU*1 | Controls the damping force of the shock absorbers based on control request signals from the driving support ECU assembly. |
*1: w/ Adaptive Variable Suspension System
OUTLINE OF PRE-COLLISION SYSTEM
PRE-COLLISION WARNING:
When the system determines that the possibility of a frontal collision is high, a buzzer will sound and a warning message will be displayed on the multi-information display to urge the driver to take evasive action.
PRE-COLLISION BRAKE ASSIST:
When the system determines that the possibility of a frontal collision is high, the system applies greater braking force in relation to how strongly the brake pedal is depressed.
PRE-COLLISION BRAKING*:
*: Depending on the region in which the vehicle was sold, the pre-collision braking function may not be available.
When the system determines that the possibility of a frontal collision is high, the system warns the driver. If the system determines that the possibility of a collision is extremely high, the brakes are automatically applied to help avoid the collision or reduce the collision speed.
Tech Tips
The vehicle may creep after the pre-collision braking function has operated, the driver should depress the brake pedal as necessary.
If the accelerator pedal is being depressed strongly or the steering wheel is being turned, the system may determine that the driver is taking evasive action and possibly prevent the pre-collision braking function from operating.
ADAPTIVE VARIABLE SUSPENSION CONTROL (w/ ADAPTIVE VARIABLE SUSPENSION SYSTEM):
When the driving support ECU determines that the possibility of a frontal collision is high, the adaptive variable suspension system controls the damping force of the shock absorbers to enhance the response of the vehicle.
PRE-COLLISION SYSTEM CONTROL OPERATION
| Control | Operating Condition | Transmitting ECU | Receiving ECU | Part Operated |
|---|---|---|---|---|
| Pre-collision warning | Possibility of a collision is high | Driving Support ECU Assembly | Combination Meter Assembly |
|
| Pre-collision brake assist |
|
Driving Support ECU Assembly |
|
|
| Pre-collision braking | Possibility of a collision is high | Driving Support ECU Assembly |
|
|
| Adaptive variable suspension control*1 | Possibility of a collision is high | Driving Support ECU Assembly | Absorber Control ECU | Absorber Control Actuator |
*1: w/ Adaptive Variable Suspension System
PRE-COLLISION SYSTEM OPERATION CONDITIONS
CAUTION:
Always observe the legal speed limit when driving on public roads.
| Specification | Pre-collision Warning | Pre-collision Brake Assist (PBA) / Adaptive Variable Suspension Control* |
Pre-collision Braking (PB) |
|---|---|---|---|
| 1 |
|
|
|
| 2 |
|
|
|
| 3 |
|
|
Not Available |
*: w/ Adaptive Variable Suspension System
| Specification | Pre-collision Warning | Pre-collision Brake Assist (PBA) | Pre-collision Braking (PB) | Pedestrian Detection Function |
|---|---|---|---|---|
| 1 | Available | Available | Available | Available |
| 2 | Available | Available | Available | Not Available |
| 3 | Available | Available | Not Available | Not Available |
Conditions under which the system may operate even if there is no possibility of a collision
In some situations such as the following, the system may determine that there is a possibility of a frontal collision and operate.
When passing a vehicle or pedestrian*
When changing lanes while overtaking a preceding vehicle
When overtaking a preceding vehicle that is changing lanes
When overtaking a preceding vehicle that is making a left/right turn
When passing a vehicle in an oncoming lane that is stopped to make a right/left turn
When driving on a road where relative location to vehicle ahead in an adjacent lane may change, such as on a winding road
When rapidly closing on a vehicle ahead
If the front of the vehicle is raised or lowered, such as when the road surface is uneven or undulating
When approaching objects on the roadside, such as guardrails, utility poles, trees, or walls
When there is a vehicle, pedestrian*, or object by the roadside at the entrance of a curve
When driving on a narrow path surrounded by a structure, such as in a tunnel or on an iron bridge
When there is a metal object (manhole cover, steel plate, etc.), steps, or a protrusion on the road surface or roadside
When a crossing pedestrian approaches very close to the vehicle*
When passing through a place with a low structure above the road (low ceiling, traffic sign, etc.)
When passing under an object (billboard, etc.) at the top of an uphill road
When rapidly closing on an electric toll gate barrier, parking area barrier, or other barrier that opens and closes
When using an automatic car wash
When driving through or under objects that may contact the vehicle, such as thick grass, tree branches, or a banner
When the vehicle is hit by water, snow, dust, etc. from a vehicle ahead
When driving through steam or smoke
When there are patterns or paint on the road or a wall that may be mistaken for a vehicle or pedestrian*
When driving near an object that reflects radio waves, such as a large truck or guardrail
When driving near a TV tower, broadcasting station, electric power plant, or other location where strong radio waves or electrical noise may be present
*: Depending on the region in which the vehicle was sold, the pedestrian detection function may not be available.
Situations in which the system may not operate properly
In some situations such as the following, a vehicle may not be detected by the millimeter wave radar sensor assembly and forward recognition camera, preventing the system from operating properly:
If an oncoming vehicle is approaching the vehicle
If a vehicle ahead is a motorcycle or bicycle
When approaching the side of a vehicle
If a preceding vehicle has a small rear end, such as an unloaded truck
If a preceding vehicle has a low rear end, such as a low bed trailer
If a vehicle ahead is carrying a load which protrudes past its rear bumper
If a vehicle ahead has extremely high ground clearance
If a vehicle ahead is irregularly shaped, such as a tractor or side car
If the sun or other light is shining directly on a vehicle ahead
If a vehicle cuts in front of the vehicle or emerges from beside a vehicle
If a vehicle ahead makes an abrupt maneuver (such as sudden swerving, acceleration or deceleration)
When suddenly cutting behind a preceding vehicle
When a vehicle ahead is not directly in front of the vehicle
When driving in inclement weather such as heavy rain, fog, snow or a sandstorm
When the vehicle is hit by water, snow, dust, etc. from a vehicle ahead
When driving through steam or smoke
When driving in a place where the surrounding brightness changes suddenly, such as at the entrance or exit of a tunnel
When a very bright light, such as the sun or the headlights of oncoming traffic, shines directly into the forward recognition camera
When the surrounding area is dim, such as at dawn or dusk, or while at night or in a tunnel
After the hybrid system has started the vehicle has not been driven for a certain amount of time
While making a left/right turn and for a few seconds after making a left/right turn
While driving on a curve and for a few seconds after driving on a curve
If the vehicle is skidding
If the front of the vehicle is raised or lowered
If the wheels are misaligned
If a wiper blade is blocking the forward recognition camera
The vehicle is wobbling
The vehicle is being driven at extremely high speeds
When driving on a hill
If the millimeter wave radar sensor assembly or forward recognition camera is misaligned
In some situations such as the following, sufficient braking force may not be obtained, preventing the system from performing properly:
If the braking functions cannot operate to their full extent, such as when the brake parts are extremely cold, extremely hot, or wet
If the vehicle is not properly maintained (brakes or tires are excessively worn, improper tire inflation pressure, etc.)
When the vehicle is being driven on a gravel road or other slippery surface
Some pedestrians such as the following may not be detected by the millimeter wave radar sensor assembly and forward recognition camera, preventing the system from operating properly*:
Pedestrians shorter than approximately 3.2 ft. (1 m) or taller than approximately 6.5 ft. (2 m)
Pedestrians wearing oversized clothing (a rain coat, long skirt, etc.), making their silhouette obscure
Pedestrians who are carrying large baggage, holding an umbrella, etc., hiding part of their body
Pedestrians who are bending forward or squatting
Pedestrians who are pushing a stroller, wheelchair, bicycle or other vehicle
Groups of pedestrians which are close together
Pedestrians who are wearing white and look extremely bright
Pedestrians in the dark, such as at night or while in a tunnel
Pedestrians whose clothing appears to be nearly the same color or brightness as their surroundings
Pedestrians near walls, fences, guardrails, or large objects
Pedestrians who are on a metal object (manhole cover, steel plate, etc.) on the road
Pedestrians who are walking fast
Pedestrians who are changing speed abruptly
Pedestrians running out from behind a vehicle or a large object
Pedestrians who are extremely close to the side of the vehicle (outside rear view mirror, etc.)
*: Depending on the region in which the vehicle was sold, the pedestrian detection function may not be available.
If the PCS warning light flashes and a warning message is displayed on the multi-information display
Tech Tips
For details on the operation of the PCS warning light and displayed warning messages, refer to Diagnosis System.
The pre-collision system may be temporarily unavailable or there may be a malfunction in the system.
In the following situations, the warning light will turn off, the message will disappear and the system will become operational when normal operating conditions return:
When the millimeter wave radar sensor assembly or forward recognition camera or the area around either sensor is hot, such as in the sun
When the millimeter wave radar sensor assembly or forward recognition camera or the area around either sensor is cold, such as in an extremely cold environment
When the millimeter wave radar sensor assembly or front grille emblem is dirty or covered with snow, etc.
When the part of the windshield glass in front of the forward recognition camera is fogged up or covered with condensation or ice
If the forward recognition camera is obstructed, such as when the hood is open or a sticker is attached to the windshield near the forward recognition camera
If VSC is disabled
If VSC is disabled, the pre-collision brake assist and pre-collision braking functions are also disabled.
The PCS warning light will turn on and "VSC Turned Off Pre-collision Brake System Unavailable" will be displayed on the multi-information display.