I've been experiencing these same symptoms - no codes being given, just the ABS shudder at low speeds which is more prominent when stopping while turning. After reading through these posts, I took my multimeter set to mvAC and checked both front-wheel sensors. At similar rotation speeds, the driver-side was outputting about half the voltage of the passenger. So, I ripped in to it and cleaned and painted that surface. I had a moment of genius and realized an expanding foam earplug made a really nice plug to keep the sensor hole sealed while working. Seems to be working great for now. I'm sure the passenger side will need attention someday, but hopefully it will hold out until time for a brake job. Thanks for the original write-up!