Try tugging the wheel if it doesn't engage right away, that usually does it for me. There is an odd entry condition that you need to have extra steering torque detected before it will go hands free.I've just found it kind of bugs out now when first trying to enable BC, occasionally while driving it'll do the same. I just had it happen today - I got on the freeway, turned it on and no pop up like normal that BC was on, did ACC with hands on BC (which usually still triggers the BC pop up). I waited a minute or two, never engaged. What has reliably fixed it for me, short of pulling over and turning the car on and off, is turning on my turn signal. I turned it on for a few clicks and boom, turned on.