SECONDARY COLLISION REDUCTION

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Purpose

Warning

•  The secondary collision reduction system operates automatically when certain conditions are met, however, it is not a system that assures prevention of a collision. There are limitations to the deceleration by the brake control.

Note

•  The secondary collision reduction system is designed to assist the driver. When the driver operates the steering wheel, accelerator pedal, or brake pedal even if the system operation conditions are met or the system is operating, the system operation is cancelled and the driver’s operation always takes priority.

Function

―  When the SAS control module determines a collision while the vehicle is stopped, it flashes the hazard warning indicator lights automatically.

•  Flashing of the hazard warning indicator lights is originally equipped on all models.

―  If the SAS control module determines a collision and detects that the vehicle starts moving at the same time while the vehicle is stopped, it operates the brakes automatically to stop the vehicle.

Construction

Solenoid valve operation table

Block diagram

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Hydraulic circuit diagram

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Operation

Flashing operation of hazard warning indicator lights

•  When the detecting vehicle is hit by another vehicle and the SAS control module determines a collision, a hazard warning indicator light request signal (1) is output from the SAS control module to the BCM.

•  When the BCM receives the hazard warning indicator light request signal, it flashes (2) the hazard warning indicator lights automatically to caution surrounding vehicles.

•  All the hazard warning indicator lights flash automatically while the hazard warning indicator lights are flashing. When the hazard warning switch is pressed 2 times, this operation is canceled.

Brake control operation

•  If the SAS control module determines a collision after detecting vehicle is hit by another vehicle when the vehicle is under any of the following conditions, brake control is performed.

•  Operation conditions

―  The selector lever is in the P position.

―  The parking brake is operating.

―  The brake pedal is depressed (electronically controlled brake unit monitors brake fluid pressure).

•  If the SAS control module detects that the detecting vehicle in a stopped condition is hit by another vehicle and moves when any of the following conditions is met, a brake control request signal (3) is output from the SAS control module to the electronically controlled brake unit. (A hazard warning indicator light flash request signal is sent to BCM at the same time.)

•  When the electronically controlled brake unit receives the brake control request signal, it energizes the pressure feed valve, switches the hydraulic circuits, and increases the brake fluid pressure. As a result, the brake control operates (4). A brake light signal (5) is output from the electronically controlled brake unit to the BCM at the same time.

•  While the brake control is operating, the brake lights turn on (6) automatically.

•  When the vehicle is under any of the following conditions, brake control is canceled.

―  The main power is not switched OFF and the electric motor is stopped.

―  Approx. 1.5 s have elapsed after the vehicle is stopped by brake control operation.

―  The accelerator pedal depression amount is approx. 20% or more while brake control is operating.

―  The brake fluid pressure higher than the pressure occurring due to the brake control operation occurs due to the brake pedal depression.

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Caution

•  If DSC control is inhibited due to a DSC system malfunction, the secondary collision reduction system is also inhibited.

•  The secondary collision reduction system does not operate in the event of a minor collision in which the SAS control module does not determine a collision.

•  If vehicle speed exceeds approx. 50 km/h {31 mph} after a collision (first collision) with another vehicle, the secondary collision reduction system operates.

•  If the SAS control module and the DSC system are damaged by a collision (first collision) with another vehicle, the secondary collision reduction system does not operate.