ABS & Trac lights come on sometimes

Hey For the past month my ABS & Trac lights come on sometimes but once i turn the car off and turn it back on again it doesnt come on again until a few days later. Then they might come back on. The car still drives good but sometimes I can feel a grinding when i press the brakes. Does the grinding of the brakes have to deal with the ABS & Trac lights. If not what do u think the problem is?
Thanks

Most likely you have a bad hub bearing speed/sensor going bad since you can feel grinding going on. Have you car scanned with an ABS capable scan tool to isolate which wheel is throwing the code. The speed sensor and hub is one unit and has to be replaced as such.

how much do u think it will cost to get that fixed?