So it was snowing heavy on Friday so I clicked the c diff lock button and drove home, later in the evening when the roads weren't as bad I pushed the button again to disengage the diff lock and all I get is the beep. I've tried all the reverse and forward and have been scouring the internet for anything that will help but so far nothing I could do in my drive way right now. Just for more info the check engine light has been on for some time now but I haven't had it checked out yet but this is the first time using the diff lock since the CEL has been on. If it is the common p0401 code could that cause the vacuum to not let the diff disengage? Sorry for my wall of text just looking for help. Hope to hear from some of you soon.