SI-Drive 2008+ STi Explained:
Brake Assist analyzes the force and stroke on the brake pedal. If the control unit senses an emergency situation, the system increases hydraulic boost to provide enhanced braking, also activating the ABS system early if needed.
The WRX STI driver also can custom-tailor the level of dynamic intervention offered by VDC. Changes are made by pushing the OFF switch on the dashboard to the left of the steering wheel column.
VDC has three settings:
- VDC – the default setting, optimized for daily driving situations. There are no warning lights associated with this mode, which enables all controls for ABS, the Traction Control System (TCS), and VDC.
- Traction – set by holding in the VDC off switch, which turns the VDC warning light green. This setting is more performance-oriented, with less-aggressive stability control. Engine torque-reduction control is disengaged.
- Off – set by pushing the off switch once. This setting turns off stability control and the traction control functions for emergency situations, such as getting out of mud or snow. It leaves ABS and incline start assist active.