Electronic Stability Control (ESC)

Have you heard your mechanic use the acronym ESC or have you read it in your owner's manual, but don't know what it means? Short for electronic stability control, ESC is a safety feature that detects and helps prevent your car from going into a skid or to recover safely if it does begin to slide. Without ESC, you have a greater chance of losing control of your car in a panic swerve or when driving on roads made slippery by rain, snow, or ice. Starting in 2012, federal laws mandated that all new vehicles under 10,000 pounds be equipped with ESC.

How the System Works

Electronic stability control is a computerized system that works by transmitting signals to the ESC control unit from individual sensors that are attached to each wheel. If a car begins to rotate in a direction different from the angle of the steering wheel, the sensors alert the system, which is then able to brake individual wheels as necessary to correct oversteering or understeering. It also slows the engine until control is regained. This allows the ESC to monitor and recover from skids that a human driver can't.

ESC vs. Traction Control

While traction control can limit wheel spin by braking to transfer spin to another wheel with more traction, stability control does that by actually maneuvering the car. Imagine driving on a snowy road. You are pointing your steering wheel straight ahead, but suddenly you start to skid to the left. Stability control will then kick in to cut power to the engine and brake the proper wheels to move the car where you are pointing the steering wheel. Traction control would only stop the skid. So think of ESC as an elevated form of traction control—ESC can do the same job as traction control, and more, but traction control cannot do the same job as ESC.

How to Know When the ESC System Is Active

Every manufacturer's ESC system works a little differently. With some systems, you may feel the car change direction slightly or hear the chattering of the antilock brake system. Other systems apply so gently as to be nearly imperceptible. Most ESC systems have a warning light that flashes when the system is active. ESC is most likely to activate on wet, snowy, or icy roads, though driving quickly on curvy, hilly roads or hitting a bump while cornering may also trigger the ESC system. Some performance-oriented systems will allow a skid to develop before stepping in.

Performance Stability Control Programs

Some high-performance cars have ESC systems that are programmed to be more permissive, allowing the car to exceed its limits of traction and actually skid a bit before the system steps in and recovers from the skid. Performance cars from General Motors, including the Chevrolet Camaro, Chevrolet Corvette, and Cadillac ATS-V and CTS-V, have multi-mode stability control systems that let the driver control the amount of intervention and protection.

Alternate Terms for ESC

Different manufacturers use different names for their electronic stability control systems. Some of these names include:

• Electronic Stability Program (ESP)
• StabiliTrak
• Vehicle Stability Assist (VSA)
• Vehicle Stability Control (VSC)
• Vehicle Dynamic Control (VDC)
• Dynamic Stability Control (DSC)
• AdvanceTrac with Roll Stability Control

Not a 100 Percent Solution

Even with ESC, it is still possible to lose control of the car, so always drive carefully in inclement weather or on curvy roads. Excessive speed, slick roads, and excessively worn or improperly inflated tires are all factors that can reduce ESC's effectiveness.