How to Clean the ABS Wheel Sensor on Your Car

Supercar brake detail, close up
Monty Rakusen / Getty Images

There are many things that can cause your anti-lock brake (ABS) light to come on. Some of those things are serious, but oftentimes it just means you need to clean the sensors. One or more dirty wheel sensors (all cars with anti-lock brakes have at least one) can cause the system to trigger the ABS light during the computer's self-evaluation cycle. Of course, you should never ignore the light, but before you drive to your mechanic and pay for someone to clean it, you can easily do it yourself. You'll be shocked when you see how much road gunk can accumulate on this very important sensor. Furthermore, since the sensor is also used in some traction control systems if you've got a traction control, or anti-skid, warning light illuminated, you might find that cleaning the ABS sensors will remedy this as well.

Even if your ABS light hasn't made an appearance, it's a good idea to clean the sensors on a regular basis. A good time to do it would be during brake pad replacement when the wheels are already off the car. At this point, it's a 10-minute job rather than an hour or two.

What You'll Need

A very dirty ABS wheel sensor.
If your ABS sensor looks like this, you might have problems. Photo by Wild Out White GSR

First, check with your owner's manual to see where your ABS sensors are located. There will be at least one and up to four. Then get your tools together. You'll need:

A clean work area really helps you stay organized by allowing you to easily keep track of tools and parts and avoid making costly mistakes. Remember, it's never safe to work on a car supported by just a jack. Use jack stands!

Safely Support the Vehicle and Remove the Wheel(s)

Car safely supported
Be sure to properly support your vehicle on jack stands. Photo by Matt Wright, 2007

Begin by loosening the wheel lugs on the front wheel or wheels (depending on where your sensors are). For safety's sake, and for better leverage, always do this while the car is still on the ground. Next, jack the front of the car up and rest it securely on your jack stands. Always be sure your car is supported securely. A wobbly car or truck can lead to a serious injury or damage to the vehicle. There's no reason to take chances when you're working underneath an elevated car. With the car safe, remove the wheel lugs and take the front wheel or wheels off.

With the wheels off, turn the steering wheel all the way in, opposite the side you're working on. For example, if you're working on the passenger side, turn the wheel all the way toward the driver's side. This will give you easier access to the ABS parts, both visually and in terms of your reach.

Remove the Wheel Sensor

Remove the ABS wheel sensor.
Remove the bolts securing the ABS sensor, then free the sensor. Photo by Wild Out White GSR

Locate the ABS wheel sensor. Remove the bolts that attach it to the rest of the suspension. You may also need to remove a few bolts that attach the wiring to the car's frame or suspension, to pull the sensor away from the vehicle for cleaning. Follow the line and/or wiring harness to see if there are more bolts. Remember not to force it or pull too hard. Along the line there are another two 10mm bolts that need to be removed—just follow the ABS sensor line to get at them. The initial bolts on this application are pictured here. Different vehicles are set up differently, but the idea is the same in most cases. The important thing to remember is never force anything to move. If you've removed all of the bolts and other attachment components, you should be able to pull the sensor away with no effort at all.

Cleaning the ABS Sensor

ABS sensor nice and clean.
Carefully clean the ABS sensor. Photo by Wild Out White GSR

With the sensor free, take your rag and wipe the sensor until it's clean. I prefer not to use any chemicals on the sensor to avoid potential problems. If, however, the sensor is really grungy, use a mild soapy solution and rinse well. The ABS sensors are precision instruments in a crude environment. They're tough enough to hang off the brakes of a very fast moving vehicle, but one good knock and they could be damaged beyond repair. Keep this in mind when working with these sensors. A little care taken now will save you a costly repair later. 

To finish the job, reinstall the sensor in exactly the same manner as you removed it. Don't skip the step of reattaching the line or wiring to those mounting points. They may seem like they don't matter, but it can get very expensive if you make a bad decision. Don't be discouraged if your ABS light doesn't turn off right away. It may take up to a few days for the system to reanalyze itself and reset fully.