Mike246

I know that this subject has been addressed in previous posts.

My '98 GS300 occasionally deploys the ABS at crawling speed. Whirring noise from under the bonnet and pulsating felt on the brake pedal. I am not aware that the ABS light comes on or whether there are any codes.

The questions are - is this a speed sensor replacement or something more sinister? How do I find out which sensor is the problem?

EITELS123

Its most likely a wheel speed sensor. You can pull the sensor and clean it as a free attempt to fix .Also make sure your tires are all properly inflated.

iToaster

The ABS sensor is probably covered in metal dust, causing the signal to degrade. The metal dust comes from the ABS speed ring on the axle rubbing the inside of the axle carrier as it rusts with time, which causes the tabs on the ring to become smaller, also degrading the wheel speed signal. Cleaning the sensor off will often fix the problem if the ring is still in decent shape.

Mike246

Thanks guys, I'll get my mechanic to remove the wheels, clean the sensors and inspect the toothed speed rings.