Hill Start Assist (From '08MY): Operation

When the driver depresses the brake to stop the vehicle on an uphill, the system recognizes that the vehicle is at a stop from the wheel speed sensor signals.

Then the G sensor detects the inclination of the road surface where the vehicle stops.

The vehicle dynamic control unit holds brake pressure for one second when the brake is released (the brake light switch OFF) and the accelerator and clutch pedals are operated.

Fig 1: Overview Of Hill Start Assist System (Without Hill Start Assist And With Hill Start Assist)

Courtesy of SUBARU OF AMERICA, INC.

Fig 2: Vehicle Dynamics Control Characteristics

Courtesy of SUBARU OF AMERICA, INC.