I'm getting a tire system fault after 20 or so miles. It started after the car had major stereo upgrade. They had the battery unhooked for days so I just figured the sensors just needed to be re-learned. I re-learned them by e owners manual and still keep getting it. I'm going to go get the sensors re-learned with progammer tomorrow and see if that changes anything. I have 2 amps on back wall of rear seat and signal processor under back deck lid. Could any of those be causing this?