2009 Chevrolet Cobalt Owner's Manual - Page 223

Brake Assist If this vehicle has ESC with ABS, it also has a Brake Assist feature designed to assist the driver in stopping or decreasing vehicle speed in emergency driving conditions. This feature uses the stability system hydraulic brake control module to supplement the power brake system under conditions where the driver has quickly and forcefully applied the brake pedal in an attempt to quickly stop or slow down the vehicle. The stability system hydraulic brake control module increases brake pressure at each corner of the vehicle until the ABS activates. Minor brake pedal pulsations or pedal movement during this time is normal and the driver should continue to apply the brake pedal as the driving situation dictates The Brake Assist feature will automatically disengage when the brake pedal is released or brake pedal pressure is quickly decreased. Electronic Stability Control (ESC) The vehicle may have an Electronic Stability Control (ESC) system which combines antilock brake, and traction and stability control systems that help the driver maintain directional control of the vehicle in most driving conditions. When the vehicle is started and begins to move, the system performs several diagnostic checks to ensure there are no problems. The system may be heard or felt while it is working. This is normal and does not mean there is a problem with the vehicle. The system should initialize before the vehicle reaches 20 mph (32 km/h). If the system fails to turn on or activate, the ESC/TCS light comes on, and the ESC OFF and/or SERVICE ESC message displays. For more information, see Driver Information Center (DIC) on page 3-43 and Electronic Stability Control (ESC)/Traction Control System (TCS) Indicator/Warning Light on page 3-31. 4-7