PRE-COLLISION SYSTEM

FUNCTION OF MAIN COMPONENTS

Item		Function
Millimeter Wave Radar Sensor Assembly		Radiates millimeter wave forward, uses the reflected millimeter waves for detecting the presence of a vehicle ahead, the vehicle-to-vehicle distance, and the relative speed. Determines whether a collision is imminent based on the information received from this sensor and forward recognition camera (camera sensor). It then outputs a brake assist standby request signal and pre-collision braking request signal if required.
Forward Recognition Camera (Camera Sensor)		Acquires a video of the area in front of the vehicle, and performs image processing to recognize obstacles or vehicles ahead, and then transmits this information to the millimeter wave radar sensor assembly. Sounds the pre-collision city buzzer to warn the driver. Operates the camera heater (forward recognition hood) to remove condensation from the part of the windshield in front of the forward recognition camera (camera sensor).
Camera Heater (Forward Recognition Hood)		Heats the sheet heater in accordance with the signals from the forward recognition camera (camera sensor).
Brake Actuator Assembly	Skid Control ECU	Receives a brake assist standby request signal from the millimeter wave radar sensor assembly, and switches the brake assist to standby mode. When a master cylinder pressure signal is input, it activates the brake assist. Receives a pre-collision brake request signal from the millimeter wave radar sensor assembly, and then applies the brakes. Transmits vehicle speed signals to the millimeter wave radar sensor assembly.
	Master Cylinder Pressure Sensor	Detects the master cylinder pressure and transmits a signal to the skid control ECU.
	Pump Motor	Receives an operation signal from the skid control ECU and generates hydraulic pressure for brake control.
Combination Meter Assembly	PCS Warning Light	Flashes or illuminates to warn the driver in accordance with signals from the millimeter wave radar sensor assembly. Flashes when the system is malfunctioning. Illuminates when the pre-collision system is not available due to when the pre-collision system is turned OFF or pre-collision braking and pre-collision brake assist operation are disabled using the VSC OFF switch.
	Master Warning Light	Illuminates to warn the driver in accordance with signals from the millimeter wave radar sensor assembly.
	VSC OFF Indicator Light	Illuminates when in the VSC OFF mode.
	Multi-information Display	Displays a warning message to inform or warn the driver of the system condition in accordance with signals from the millimeter wave radar sensor assembly.
	Multi Buzzer	Sounds to warn the driver in accordance with signals from the millimeter wave radar sensor assembly when the system is malfunctioning.
ECM		Transmits an accelerator pedal opening angle signal and shift position signal1 or reverse position signal2 to the millimeter wave radar sensor assembly. Controls engine output based on the signal from the millimeter wave radar sensor assembly.
Airbag Sensor Assembly		Detects the yaw rate and lateral/longitudinal deceleration of the vehicle and transmits the signal to the millimeter wave radar sensor assembly.
Network Gateway ECU		Relays and transmits each CAN communication data signal.
Spiral Cable with Sensor Sub-assembly	Steering Angle Sensor	Detects the steering direction and angle of the steering wheel and transmits the signal to the millimeter wave radar sensor assembly.
Pre-collision City Buzzer		Sounds to warn the driver in accordance with signals from the forward recognition camera (camera sensor).
Electric Parking Brake Switch Assembly	VSC OFF Switch	Disables the pre-collision braking and pre-collision brake assist operation when the switch is turned on. The PCS warning light illuminates to show that the pre-collision braking and pre-collision brake assist operation is disabled. The pre-collision warning function can still operate.
Speed Sensor		Detects the wheel speed and transmits signals to the skid control ECU.
Ambient Temperature Sensor (Thermistor Assembly)		Detects ambient temperature and outputs it to the combination meter assembly.
Stop Light Switch Assembly		Detects the depressing of the brake pedal and transmits a signal to the skid control ECU. Illuminates the stop lights in accordance with the signals from the skid control ECU.
Accelerator Pedal Sensor Assembly		Detects the amount of pedal effort applied to the accelerator pedal and transmits the signal to the ECM.
Park/Neutral Position Switch Assembly*1		Detects the shift position and sends the signal to the ECM.
Back-up Light switch Assembly*2		Detects the reverse position and sends the signal to the ECM.
Steering Pad Switch Assembly		Switch the display of multi-information display within combination meter assembly.

*1: Models with CVT

*2: Models with manual transaxle

FUNCTION

Tech Tips

Depending on the region in which the vehicle was sold, the pedestrian detection function may not be available.

The pre-collision system uses a millimeter wave radar sensor assembly and forward recognition camera (camera sensor) to detect vehicles and pedestrians in front of your vehicle.
When the system determines that the possibility of a frontal collision with a vehicle or pedestrian is high, a warning operates to urge the driver to take evasive action and the potential brake pressure is increased to help the driver avoid the collision.
If the system determines that the possibility of a frontal collision with a vehicle or pedestrian is imminent, the brakes are automatically applied to help avoid the collision or help reduce the impact to the vehicle occupants and the vehicle in the collision.
1. Pre-collision warning
  - When the system determines that the possibility of a frontal collision is high, a pre-collision city buzzer will sound and a warning message will be displayed on the multi-information display to urge the driver to take evasive action.
2. 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.
3. Pre-collision braking
  - 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 frontal collision is extremely high, the brakes are automatically applied to help avoid the collision or help reduce the collision speed.

OPERATING CONDITION

Availability of the pedestrian detection function depend on the region the in which the vehicle was sold.

Regions	Function availability
Region A	The pedestrian detection function is available
Region B	The pedestrian detection function is not available

Region A (The pedestrian detection function is available)
1. The pre-collision system is enabled and the system determines that the possibility of a frontal collision with a vehicle or pedestrian is high. Each function is operational at the following speeds:
  - Pre-collision warning:
  - Pre-collision brake assist:
  - Pre-collision braking:
2. The system may not operate in the following situations:
  - If a battery terminal has been disconnected and reconnected and then the vehicle has not been driven for a certain amount of time
  - If the shift lever is in R
  - If VSC is disabled (only the pre-collision warning function will be operational)
Region B (The pedestrian detection function is not available)
1. The pre-collision system is enabled and the system determines that the possibility of a frontal collision with a vehicle is high. Each function is operational at the following speeds:
  - Pre-collision warning:
  - Pre-collision brake assist:
  - Pre-collision braking:
2. The system may not operate in the following situations:
  - If a battery terminal has been disconnected and reconnected and then the vehicle has not been driven for a certain amount of time
  - If the shift lever is in R
  - If VSC is disabled (only the pre-collision warning function will be operational)
Cancelation of the pre-collision braking
1. If either of the following occur while the pre-collision braking function is operating, it will be canceled:
  - The accelerator pedal is depressed strongly.
  - The steering wheel is turned sharply or abruptly.
Conditions under which the system may operate even if there is no possibility of a collision
1. In some situations such as the following, the system may determine that is a possibility of a frontal collision and operate.
  - When passing a vehicle or pedestrian
  - When changing lanes while overtaking a vehicle ahead
  - When overtaking a vehicle ahead that is changing lanes
  - When overtaking a vehicle ahead that is making a right/left 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 pales, 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 vehicles, 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
  Tech Tips
  
  Depending on the region in which the vehicle was sold, the pedestrian detection function may not be available.

SYSTEM CONTROL

Pre-collision Brake Assist
1. While the pre-collision system has determined that there is a high possibility of a collision, brake hydraulic pressure assistance is performed when the driver depresses the brake pedal. Also, the amount of brake hydraulic pressure assistance increases further when the system determines that there is an even higher possibility of a collision.
Pre-collision Braking
1. When the pre-collision system detects an object such as a vehicle or road structure in front of the vehicle and determines that the possibility of a collision is high, the system displays a warning message on the multi-information display, and sounds the pre-collision city buzzer to warn the driver.
2. When the pre-collision system determines high possibility of collision, the system performs pre-collision braking control.

DIAGNOSIS

Initial Check
1. The millimeter wave radar sensor assembly performs an initial check on the system for approximately 3 seconds after the ignition switch has been turned to ON.
Monitor Function
1. After completing the initial check, the pre-collision system becomes ready to operate. During this time, the millimeter wave radar sensor assembly periodically monitors the system for any malfunctions.
Diagnostic Trouble Code (DTC)
1. If the millimeter wave radar sensor assembly detects a malfunction in the pre-collision system, it stores a Diagnostic Trouble Code (DTC) in memory.