Depends on the year. Pre 1996 you can check the diagnostic boxes and it will tell you what is wrong. 1996 and later, you are doing a guessing game as to what is wrong. Many code readers will not give you the ABS error codes, and the generic scanners do a poor job.

Yes, it could be dirty sensor rings - usually on the rear hubs. 1996+ do have solder issues which can be repaired, but the module has to come out of the car and you need the correct solder to fix it. Vic can repair it, but that is around $100:
http://home.earthlink.net/~vicrocha/

Traction control makes use of the ABS, so if the ABS is not functioning, neither will TRKS. Of course, this only applies to locked up brakes, hard accelleration under 25mph, and increased wear on the rear brake pads.

Remember, the ABS does a self-check at around 17-18 mph and if it all works, the ABS light will go out. You cannot turn off the ABS light by disconnecting the battery.
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