Speed sensors work in conjunction with your Mazda's anti-lock braking system (ABS). The sensor sends information relating to the speed of the car to the ABS. The speed sensor in a Mazda collects dust from the road as the car brakes. The sensor needs to be kept clean or the anti-lock braking system will not work efficiently. The job is fairly straightforward and requires basic tools.
Gather all tools and material and put them within easy reach. Put on protective clothing and gloves, if you need them.
Raise the front of the Mazda with a jack and lower it carefully onto jack stands. Loosen the lug nuts with the lug wrench and remove them. Take the wheel off.
Find the sensor and the reference ring at the back of the brake rotor.
Detach the sensor with the screwdriver. Remove it carefully from the bracket. Be careful with the cables as well.
Apply degreaser to the cloth and carefully wipe the sensor. Clean the tip of the sensor gently, and avoid scratching or damaging it.
Apply degreaser to a stiff nonmetallic brush. Clean the reference ring with the brush until all dirt has been removed.
Reinstall the sensor and screw it into place. Remount the wheel back and secure it with the lug nuts. Tighten the lug nuts with the lug wrench. Repeat this on the other front wheel sensor.
Raise the front of the Mazda above the jack stands. Remove the stands and lower the vehicle to the ground. Repeat the process for the back wheel sensors.