My 2003 Audi A4 turbo manual ABS warning light comes on intermittently and often. The traction stability light comes on at the same time since it is dependent upon the ABS. It happens sometimes at startup and will go off if I turn the ignition off and then back on. It also comes on sometimes when I am stopped at a light after driving. The speedometer doesn’t work when the warning lights are on. I have felt the ABS activate a few times when not needed. Is this a computer issue or is there a deeper issue with the ABS?