2002 Mazda Protege ABS & Brake light

It is most likely caused by one of the ABS wheel speed sensors, those little cylindrical nipples on the back of your rotors with the cable attached to them. One way to confirm it is to read out the OBD2 codes for the ABS system, but there are some checks you can do. Visually check all four cables and sensors , and make sure there is no build up on the sensors. Make sure that the connector they plug into has good connections. Look at the wheel speed sensor and make sure the gap between the sensor head and the sprocket is the same on all four wheels (should be no more than a mm). Disconnect the wheel speed sensor cable and use an ohm-meter to check the resistance of all four sensors (they should all be similar, but don't remember the value exactly). There is a way to just disable the ABS by pulling out the 60A fuse, but if you do that you may have to plug in a code reader and use a grounding jumper on the ABS electical access box (don't remember which pin) to reset the ABS faults, otherwise you won't be able to drive around like that because your engine rpm at high speeds will behave erratically. Also, do not drive around without fixing this problem or bypassing ABS completely because it could get you into an accident. My ABS problem was intermittent, and the ABS would sometimes kick in on completely dry pavement as soon as I touched the break pedal, it almost caused me to rear-end a car on couple of occasions.

I dont have a solution, but wanted to let you know my mazda has done the same thing, starting with the right rear sensor. the comment above is helpful.