What it is: Traction Control is an electronic system that automatically keeps the drive wheels (either front, rear, or both in the case of an AWD or 4WD vehicle) from spinning during acceleration. This improves traction and vehicle stability in slippery driving conditions. Also known as Electronic Traction Control.
How it works: A microprocessor compares the rotational speed of the vehicle's front and rear wheels while also tracking such values as throttle opening. When one of the drive wheels loses traction its rotational speed quickly rises compared to that of the other wheels. When this happens, the electronic control unit signals the engine to reduce power output and/or rapidly pulses the brake for the wheel that is spinning. The brake pulsing is done via the Anti-lock Braking System hydraulic pump. All cars that have Traction Control also have ABS (see above).
What it feels like: Traction Control activation can feel somewhat different from vehicle to vehicle. When the system activates there is generally a momentary delay in acceleration as the spinning wheel is brought under control. Then the vehicle smoothly accelerates ahead.
How it benefits the driver: The most important benefit of Traction Control is that it helps the driver retain control while accelerating on slippery surfaces such as snow, ice or water-or even dirt roads or trails for SUVs. It can also help high-powered cars maintain traction in a straight line or while accelerating on roads that have rough or uneven pavement.