Four problems related to brake antilock control unit/module have been reported for the 2002 Subaru Impreza Wrx. The most recently reported issues are listed below.
Abs activates on bumpy roads.
When I am braking on an uneven surface, such as a pothole, or sometimes on gravel, the abs will be triggered, causing a loss of braking pressure which causes the braking distance to be extended considerably. I have not gotten into an accident as a result of this, yet, but I am worried as I can't be monitoring pavement conditions everytime I apply my brakes.
When braking on uneven or rough surfaces, the abs brakes fail and the brake pedal goes to the floor. I have to get off abs and get back on quickly; this is the opposite of the proper way to use abs brakes.
My 2002 Subaru wrx has a defective abs system. When braking moderate to hard and the car hits a bump, the abs "kicks in" and reduces brake pressure, but after the road has settled the brake pressure doesn't return. You can press the brake pedal to the floor but brake pressure doesn't increase. Only if you lift your foot completely off the brake pedal and then reapply, does braking power return. This is dangerous and could cause an accident if you have to panic stop and there is an imperfection in the road. My car has done this since I took delivery March 13th, 2001.