How to Clean an Abs Sensor

Your vehicle's anti-lock braking system (ABS) keeps the tires from locking up when you brake, helping you stay safe on the road. If you notice the ABS light lit up on your dashboard, that means something is interfering with the sensor....

Part 1 of 3:

Accessing the ABS Sensor

Lift your vehicle using a car jack so you can safely remove the wheels. Park your car on a hard flat surface and turn off the engine. Position the car jack at the jack point and carefully engage the jack. Lift the car off the ground until there is about 1 to 2 inches (2.5 to 5.1 cm) of clearance under the wheel.^{[1] X Research source}
1. If you don't know where your vehicle's jack points are, check the owner's manual. Generally, there is a flat metal area behind each front wheel and in front of each back wheel.
Which Wheel to Access: Depending on what type of vehicle you have, there may be an ABS sensor in each wheel—check your owner's manual for verification. If you have access to an ABS scanner, it can tell you which sensor is faulty. If you don't have a scanner, you'll need to systematically clean each sensor until the ABS light turns off.
Loosen the lug nuts from the tire and remove the wheel from the vehicle. Use a wrench to remove the lug nuts, then set them in a small bowl off to the side so they don't get lost. Pull the wheel off of the tire hub and move it out of the way so you have room to work.^{[2] X Research source}
1. If the wheel seems stuck to the hub, use a rubber mallet to tap it loose.
Locate the ABS sensor along the body of the wheel hub. Find the reference ring, which is the bolt or covering that holds the sensor in place. It's usually located along the wheel hub—you can start by locating the electrical wire that leads from the wheel and connects the sensor to the vehicle to help yourself find it a bit more easily.^{[3] X Research source}
1. It can be a little tricky to access the sensor sometimes, just depending on how the wheel is turned. It's usually located around the backside of the hub.
2. If you can't find the sensor, your vehicle may have 'disguised' sensors rather than 'open sensors. Disguised sensors are usually located internally in the wheel hub and usually don't need to be cleaned because they're protected from dirt. If you are having a problem with a disguised ABS sensor, you'll need to take it to a mechanic.
Remove the bolt covering the ABS sensor with an Allen wrench. Loosen the bolt and keep turning the wrench until it comes off completely. Place the bolt into the bowl with the lug nuts.^{[4] X Research source}
1. If the bolt is really rusty or not turning easily, spray it with WD-40. Wait a few minutes, and then try again to remove it.
Wiggle the ABS sensor loose with a pair of pliers. Don't pry the sensor up from the bottom, as that could cause irreparable damage. Instead, grasp the sensor with the pliers and gently move it back and forth until it pops out.^{[5] X Research source}
1. If the sensor isn't coming away from the tire hub, try repositioning your pliers on alternate sides or wiggling the sensor in a circular motion to dislodge any rust or dirt that is holding it in place.
2. The sensor is connected to the car by a wire; there isn't any reason to detach the wire, so just leave it in place.

Part 2 of 3:

Removing Dirt from the Sensor

Blow canned air into the area where the sensor was lodged. This removes any dirt or bits of metal that may have fallen in. Either turn your face away or put on a pair of safety goggles so nothing accidentally gets into your eyes.^{[6] X Research source}
1. Don't try to wash the area out—water will cause more issues.
Wipe dirt and debris off the sensor with a clean, dry microfiber towel. Chances are that there was some kind of interference between the sensor and the wheel causing your ABS light to come on. It's common for the sensors to accumulate grime and small bits of metal—gently wipe the entire surface of the sensor, rubbing away any visible dirt.^{[7] X Research source}
1. This is a fairly quick process and shouldn't take more than a minute. Even if you have to do it to each sensor, the task should only take you an hour or so in total.
Using Cleaning Solutions: Avoid using any type of chemical cleaning solution on the ABS sensor. It could damage the sensor, meaning you'd have to replace it with a new one. If you need to, use warm, soapy water to scrub away dirt from the sensor—just make sure that the sensor dries completely before you replace it.
Use a wire brush or file to gently grind away stubborn rust or dirt. Be careful if you do choose to do this, as excessive cleaning could damage the sensor. Don't use a lot of pressure—instead, go over the specific section repeatedly with a light touch until it comes clean.^{[8] X Research source}
1. This most often needs to be done with older vehicles and with sensors that show a lot of rust.

Part 3 of 3:

Reinstalling the Sensor

Push the sensor back into place so the wiring is exactly as it was before. Once the sensor is cleaned, gently reposition it and push it down to make sure it is securely in place. If you have a hard time getting it back in, there may be a blockage of some sort—try blowing canned air into the hole again.^{[9] X Research source}
1. Avoid twisting or screwing the sensor—that could damage it.
Replace the bolt and twist it to secure the sensor in place. Get the bolt out of the small bowl where you placed your lug nuts. Put the bolt over the ABS sensor and tighten it with a wrench.^{[10] X Research source}
1. When you get to the end and start to feel resistance, give the bolt just one final twist. You want it to be on tightly enough that it won't come loose, but you also don't want it to be too hard to remove the next time you need to clean the ABS sensors.
Reposition the wheel and screw the lug nuts back in place. Place the wheel back on the tire hub. Put all the lug nuts back on, taking care to make sure they are all tightly screwed on. Once the wheel is back in place, you can disengage the car jack.^{[11] X Research source}
1. You can probably use your hands to start screwing on the lug nuts, but finish them off with a wrench.
Repeat the process on each wheel until the ABS light no longer lights up. After you finish the first tire, go ahead and start your vehicle and check if the ABS light is gone. If so, you fixed the problem on the first try! If not, tackle the next wheel with a sensor.^{[12] X Research source}
1. If you were able to check an ABS scanner before beginning this project, you may already know exactly which wheel was the problem.
2. If the ABS light is still coming on after all the sensors are cleaned, there may be an internal or wiring problem. Visit an auto body shop to have the fault code read to see what else needs to be done.