Why Your Traction Control Warning Light Is On, and What to Do

The traction control system (TCS) in your vehicle is responsible for helping your vehicle maintain its grip in slippery conditions, such as rain, snow or ice. If a wheel loses traction, the TCS kicks in to keep your car stable and on course.

Working in conjunction with your anti-lock braking system (ABS), traction control provides you with an extra margin of safety. The system operates through a computer and a network of sensors, all of which must work properly to keep you safe.

Why is the traction control warning light on?

First of all, you should be aware that there is a situation when it’s OK for the TCS light to come on. One of the warning light’s primary functions is to alert you that the system is in operation. This usually happens in slippery conditions, when your wheels are more likely to spin. The TCS warning light can flash, or it may remain on while the system is working.

However, if you’re driving in normal conditions that shouldn’t trigger the TCS, and the warning light comes on, there may be a fault in the system. This should be taken seriously — the system can keep you from having a wreck in bad weather. It will need to be diagnosed and repaired by a mechanic — it’s not a do-it-yourself kind of deal.

Your vehicle has temporarily lost traction

The TCS warning light will pop on when the system detects a loss of traction, like in snowy or rainy weather. Typically the light is seen when the system intervenes to maintain traction. It may light up for a brief period and then go off, or it may flash while it is operating.

Solution: This is normal — your traction control is operating properly and notifying you of that fact. Read the TCS section in your owner’s manual to familiarize yourself with it.

You have a defective wheel speed sensor or sensor wiring

Your TCS is controlled by a set of wheel speed sensors, located at each wheel, and shared with your ABS system. These sensors provide a constant flow of information to your traction control computer about whether each wheel is rolling normally, or if it is slipping or spinning. The data from the sensor on each slipping wheel activates the TCS, which brakes or cuts the power to that wheel. This lets the wheel regain its traction.

A defective, dirty or corroded wheel speed sensor, or a fault in the wiring that connects it, will keep the proper information from getting to the TCS computer, preventing the traction control on that wheel from working. This can cause the system to stop functioning, illuminating the TCS warning light.

Solution: A professional mechanic can diagnose a faulty sensor or wiring with a specialized scan tool and replace the defective parts.

Your TCS computer has failed

The traction control computer in your vehicle is the “brain” that controls the entire system. A defect, corroded contacts or water damage in this computer can result in the entire system going offline, which will turn on the TCS warning light. As the TCS and ABS often share a computer, this may affect your ABS system and turn on that light, too.

Solution: A diagnostic scan can reveal a computer failure. Repair or replacement will be necessary to restore your TCS, and possibly ABS, to normal.

Get it diagnosed by a professional

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Can I drive with the traction control warning light on?

If the traction control light comes on while you’re driving, but no other warning lights are illuminated, don't panic. Find a safe place to pull over, turn off your vehicle, and then restart it. If a fluke in the TCS system triggered the warning light, it should turn stay off when you restart the engine.

If it comes back on, it's likely time to call a mechanic and get a system diagnosis. Until it’s fixed, drive gently and avoid hard acceleration that could result in the wheels slipping. If the ABS light also comes on, the above advice also applies, with the additional precaution of avoiding hard braking that could provoke a skid.

If the TCS and the ABS warning lights both come on, along with the red main brake warning light, you should not drive the car until the problem has been fixed. Your entire braking system is affected, and may not be able to stop your vehicle when you need it to. Have your vehicle towed to a repair shop.

Proper diagnosis of TCS issues usually requires a specialized scan tool to find the trouble code that has triggered the warning light. The specific trouble code can help identify which component is causing the fault, as well as its specific location.

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When should you switch off your traction control?

Many vehicles with traction control have a switch that lets you temporarily turn it off. The switch is usually marked “TCS Off” or “ESC Off.” Once you switch it off, it will stay off until you either switch it back on or turn off and restart your vehicle. Check your owner’s manual for more details on how this switch works.

Here are a few situations when you might want traction control to take a rest.

When starting in snow

When starting from a stop in snowy conditions, all of your wheels can easily slip. When this happens, the TCS can intervene, keeping you from moving. Disabling the system lets your wheels move enough to get forward traction.

When stuck in mud or snow

If you get stuck in deep mud or snow, you’ll want to turn off the system in order to let the wheels spin and generate some grip. This will allow you to rock the car back and forth by shifting between drive and reverse repeatedly. If you’re successful, you’ll be able to build enough momentum to free your vehicle.

When using tire chains

It can be useful to switch off the TCS if chains are required on icy and snowy roads. A certain amount of wheel slip is normal under these conditions, and the constant intervention of traction control may be an unwelcome distraction.