By now you should already know that the 2012 Chevy Sonic will debut with a segment-exclusive feature called Hill Hold Assist, which prevents a Sonic with a
real manual transmission from rolling backward or forward when starting on a hill. In the video that follows, Sonic lead development engineer John Buttermore explains how Hill Hold Assist works.
For starters, Hill Hold Assist uses the Sonic’s chassis control system (in this case, the electronic brake modulator) to hold the vehicle from rolling backwards when on a hill facing up) or forwards (when on a hill facing down). This chassis control system is comprised of three sensors detecting yaw, pitch, and steering angle that interact with the (standard on all models) Stability Control and ABS systems of the car.
The pitch sensor can detect whether the Sonic’s nose is pointing up (on a five percent grade) and, upon being thrown into first gear and sensing the release of the brake pedal, will continue to apply the brakes for two seconds. The same holds true when the Sonic’s nose is pointing down (also on a five percent grade) and the driver shifts into reverse.
At the end of the day, Hill Hold Assist holds the Sonic in place for two second after the driver releases the brake pedal, allowing for the proper blend of clutch and gas for a smooth takeoff. What’s more, the brake light continues to stay on when the driver releases the brake pedal and Hill Hold Assist is activated, providing the right communication to the driver behind the Sonic. The GM Authority crew finds this implementation nothing short of ingenious, but we wonder whether the same tech will make its way to the Sonic’s twin — the Aveo — elsewhere in the world. Now, without further ado, let’s let John show you how it’s done.