EMERGENCY STOP SIGNAL SYSTEM (ESS)

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Outline

•  The emergency stop signal system (ESS) warns the driver of a vehicle following behind of an emergency braking situation by automatically and rapidly flashing the hazard warning lights when the vehicle decelerates suddenly while traveling at high speeds.

Function

•  The body control module (BCM) gives priority to the emergency stop signal system (ESS) operation even if the turn switch signal is received during the emergency stop signal system (ESS) operation.
•  When the body control module (BCM) receives a hazard warning switch on signal during the emergency stop signal system (ESS) operation, it stops the emergency stop signal system (ESS) operation and gives priority to the hazard warning light flashing operation.
•  The body control module (BCM) controls the emergency stop signal system (ESS) based on the following signals:

Signal name

Sending module/part name

Communication method
Brake switch condition signal
Electronically controlled brake unit
CAN
Vehicle speed signal
Wheel speed (LF, RF, LR, RR) signal
ABS operation condition signal
Vehicle acceleration speed signal

•  The emergency stop signal system (ESS) has two warning modes; the sudden deceleration hazard warning mode in which the hazard warning lights flash rapidly, and the emergency stop hazard warning mode in which the hazard warning lights flash normally.

Sudden deceleration hazard warning mode

•  The sudden deceleration hazard warning mode operates when the brake pedal is depressed while driving at a vehicle speed of 60 km/h {37 mph} or more and emergency braking is determined based on the vehicle's deceleration.
•  When the sudden deceleration hazard warning mode operates the hazard warning lights flash at 3.5 Hz.
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Emergency stop hazard warning mode

•  When the brake pedal is depressed at a vehicle speed of 10 km/h {6.2 mph} or less after the sudden deceleration hazard warning mode operates, the modes switches to the emergency stop hazard warning mode.


Structure/Construction


System structure

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System wiring diagram

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Operation

1.  If the brake pedal is depressed and the vehicle is decelerated while the vehicle is driven, the body control module (BCM) calculates (1) the vehicle deceleration speed based on the wheel speed signal and the vehicle acceleration speed signal.

2.  If the vehicle speed is approx. 60 km/h {37 mph} or more when the calculation is finished, and the calculated deceleration speed is the set value or more for the sudden deceleration hazard warning mode (2), the body control module (BCM) controls (3) the flashing of the hazard warning lights at 3.5 Hz (sudden deceleration hazard warning mode) and sends (3) a turn signal/hazard warning indicator lights on signal to the instrument cluster simultaneously.

3.  The body control module (BCM) stops (5) the operation of the sudden deceleration hazard warning mode if it receives (4) a brake switch off (brake pedal not depressed) signal or if the estimated deceleration value is the set value or less for stopping the sudden deceleration hazard warning mode.

4.  When the body control module (BCM) receives (6) a brake switch on (brake pedal depressed) signal at a vehicle speed of 10 km/h {6.2 mph} or less after the sudden deceleration hazard warning mode operates, it controls (7) the flashing of the hazard warning lights at 1.5 Hz (same as normal flashing) (emergency stop hazard warning mode).

5.  When the body control module (BCM) receives the brake switch off (brake pedal not depressed) signal and vehicle speed signal and determines that the vehicle has started, it stops the operation of the emergency stop hazard warning mode and turns the hazard warning lights off (8).

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