2004 Saab 9-3 Owner's Manual - Page 165

Starting and driving 165 Electronic Stability Program (ESP) Anti-skid system WARNING When driving normally, the ESP system helps to improve the car's directional stability. The ESP must not be regarded as a system to enable the driver to maintain higher speeds. The same precautions must be adopted as normal for safe cornering and driving on slippery roads must be adopted. The Electronic Stability Program employs both the antilock braking system (ABS) and the traction control system (TCS). It is a safety system that helps the driver to stabilize the car in unusual circumstances that can otherwise be difficult to handle. How the ESP system works The Electronic Stability Program can help to prevent the car from skidding by braking one or several wheels independently of the driver. The engine output is then also reduced to prevent the driving wheels from spinning. The car has sensors that measure wheel speed, yaw rate, lateral acceleration, steering wheel position and braking pressure. The values provided by these sensors are used to calculate the actual direction of the car, the intentions of the driver and whether the ESP should be engaged. If this direction does not agree with that intended by the driver, calculated from the steering wheel position, the ESP is engaged. The ESP improves the driver's chances of retaining control over the car in critical situations. Illustration of how the system applies the brakes on one or several wheels to help avoid a skid