Hear that there are many very small passages in the ABS unit. If the brake fluid gets dirty it will resrict the flow and cause a light to come on. I've been sucking out the fluid in the MC and putting in clean fluid for many years on the old trucks every third oil change. Also hear that if you change brake pads and push the fluid back in the lines instead of out the bleeders it will do the same thing. Might try new fluid and bleed the system at all bleeders, see what happens. Whole lot cheaper than taking it to a dealer/stealer.