Abs Light

The ABS and trac off light have been on in my 2004 GT since I bought it one year ago. I have replaced all brake pads, rotors, and calipers. I have thoroughly cleaned the ABS rings on all wheels; however, the lights are still on. I have been able to turn them off with a diagnostic reader, but they do not stay off. No codes show up when I use my cheap reader and I took it to a shop and their brand new scan tool would not connect to the car to read the ABS code, but could connect to the ECU. Should I replace the ABS module?

Thank you for your help I will look into that some more. From my understanding the shop I went to, owned by a friend, had a scan tool able to communicate with the ABS module. As you could understand, he was just as upset as I was that it couldn't, considering it was his first time using his new $2500 tool