How Traction Control Works

What is Traction Control?

So, what does traction control do? As its name suggests, traction control is a vehicle safety element that allows vehicles to take full advantage of road traction, especially when there is not much of it. That is, the system controls your vehicle’s performance when driving conditions on the road result in low traction stemming from insufficient friction between your tires on the road. Low friction on the road may be due to snow, rain, ice, gravel or something else. When cornering, it can result from incomplete contact on the asphalt as your vehicle slightly leans in the turn.

When you try to accelerate, your vehicle’s tires must grip the road. If there is not much traction, your wheels may slip. That is, your tires may spin rapidly without moving your vehicle forward. When necessary, your car’s traction control system engages. The system uses whatever traction is available to keep your car moving, most frequently it does this by slowing the wheel that is losing traction using the ABS system or an electronic throttle system.

Unfortunately, if there is no available friction, the traction control system cannot create its own. Therefore, if you are driving on a nearly frictionless road, such as an ice-covered one, your vehicle may perform the same whether or not the traction control system engages. Still, because all roadways offer at least some friction, your vehicle’s traction control system is likely to make a noticeable difference, and could even prevent an accident.

A Brief History of Traction Control Systems

Luxury vehicle manufacturers, such as Mercedes-Benz and BMW, and others including Toyota began installing traction control systems on some high-end sedans in 1987. Nonetheless, the technology first appeared in the early 1970s on a few powerful rear-wheel drive vehicles. Today, virtually all cars with anti-lock brakes feature some type of traction control.

How Does Traction Control Work?

Traction control can be incredibly useful when accelerating from a stop at a low-traction intersection. It can also assist you when climbing an icy hill.

The mechanics are reasonably simple. The system functions a lot like your vehicle’s anti-lock braking system. In fact, on most modern vehicles, anti-lock brakes and traction control systems are integrated.

To understand traction control, you must understand the parts that make up the system. Typically, traction control uses the following three components:

• A hydraulic moderator
• Wheel-speed sensors
• An electronic control module

When you are driving, wheel-speed sensors relay how quickly each wheel is moving. If one wheel starts to spin faster than the others, there is a good chance that wheel has lost traction or is skidding. The electronic control module uses an algorithm to determine when to engage the hydraulic moderator. This, in turn, activates the brakes in quick pumps to reduce wheel speed and improve traction.

In more advanced traction control systems, the vehicle’s engine also comes into play. With these vehicles, if a wheel is losing traction, engine power to the wheel decreases. Whether you have a conventional traction control system or an engine-incorporated one, the result is the same: wheel speed drops to improve traction.

Traction control systems engage automatically. As such, you may not realize there is a traction issue, until the light illuminates on your instrument cluster. On the other hand, if your vehicle has a traction control system that involves decreasing engine power, you may feel a minor vibration when the system engages.

What are the Pros and Cons?

Clearly, traction control systems are beneficial in low-traction situations. After all, no driver wants to spin out of control when trying to move forward, or really ever. Still, traction systems can be problematic in some driving conditions. For example, if you are getting your vehicle unstuck from a very slippery or soft surface, all of your wheels may have difficulty gripping. If your vehicle’s engine cuts the power to four wheels, you may not make enough power to get unstuck.

To combat this problem, many vehicles give the driver the option of turning off the traction control system. Typically, this involves depressing a button on the dash or interior console. If you do so, your wheels continue to receive full power. While they may spin, you may have sufficient forward motion to get unstuck. Once you’re unstuck, it’s generally wise to put the traction control back on again.

You should realize, though, that while many vehicles allow you to disable traction control, pushing the button may not completely override the system. Nonetheless, these vehicles often offer you the opportunity to select a low-traction setting. Once you pick the right option, your vehicle delivers reduced torque that both controls wheel spin and delivers forward motion.

Traction control may also lure drivers into a false sense of security. The system is made to help you out if you skid, but it’s not license to drive like mad. While the system is one of many safety features on your vehicle, you can diminish its effectiveness by driving improperly. For example, if you are speeding for conditions, your vehicle’s traction control system may not do much good. Furthermore, if you follow too closely, you may slide into another vehicle or a stationary object before your vehicle’s traction control system has an opportunity to stop the skid.

Common Problems

As with any complex system, your vehicle’s traction control may wear out or break completely. Fortunately, if there is a problem, a warning light will illuminate on most vehicles. Here are some common problems with traction control systems:

• Bad wheel speed sensors
• Electrical shorts
• Connector failure

Diagnosing a problem with a traction control system can be challenging. Nonetheless, if you have an OBD-II diagnostic reader, an issue with the traction system may register a trouble code. You should realize, though, that a traction light may illuminate if your vehicle goes into limp-home mode. This may be due to a problem with the traction control system or another component on your vehicle.

Now that you understand what is traction control, you can better plan for using your vehicle’s enhanced safety features. You can also monitor your traction control system for signs of disrepair or damage. If you see any, find the high-quality replacement parts and tools you need for your project and order them today.