47
Vehicle Dynamics and Driver Assist Systems
May 2017
Emergency Braking
The EPB can also serve as an emergency brake that can be activated while the vehicle is
in motion. Pulling up on the EPB control lever and holding the lever upward will activate the
Emergency Brake. The 2015 Legacy and Outback Emergency Brake will first attempt to slow
down through the use of the normal hydraulic components. The Motor Relay and Valve Relay in
the HCU will activate, supplying hydraulic pressure to all brake calipers (Front and Rear). Once
maximum braking is occurring (just before wheel lock up), the pump will turn off and hold mode
of ABS will maintain the current braking pressure. The EPB motor will activate only after the
vehicle speed drops below a set value.
If hydraulic pressure cannot be established, the EPB motor will activate immediately. The rear
wheels will lock up and unlock while the EPB switch is held in the on position. The EPB control
unit (HCU) will control the application and release of the EPB based on wheel speed sensor
input and always pulse the two sides together.
Emergency Brake ON
2-40
To Next Page
Loading...
