Oh I don't envy you, love! Boys can be monstrous at that age!
When DS was 15 and in that stage, grounding was the last thing that would have worked on him. If there are doors or windows in the house, as I suspect there may be, he'll be getting out!
I would try, as PP have suggested, removing things he wants/enjoys off him, eg phone, treats, any allowance, etc - things that get him about. The phone you might be reticent to remove as that's his lifeline in case he's in any trouble, so maybe you could get him a completely featureless throwaway type phone until he straightens up, and take away his fancy iphone or whatever? Get a cheapo nasty one that basically only makes calls?
I would think if you did anything at home, like change the wifi pw or whatever, that would only make him want to leave more.
Really, what finally worked for me was just a quick, calm, but very serious chat letting him know LOOK SON, I don't care (not true, but it's what he wanted to hear) what he's doing or who he's with, I just need to know that he's safe, alive, not in police custody or hospital, and if he would simply let me know where he is, then I'll leave him alone. That is literally ALL I ask - tell me you're safe. You do understand why I need that, yes? Also, if he ever needs me - is stranded, mates being shits, too drunk to get home safely, whatever - he can always call me for help and I won't say a word. Having to call mummy is punishment enough.
I know it's the last thing you want, but when they're nearly physically grown men but mentally still just boys in a lot of ways and in that mindset, I just don't know what else you can do!
At that age - basically overdosing on testosterone and confusion (the poor lad), taller than me by several inches, soooo much stronger than me, etc - that was just about all I could do.
Anyway that's what worked FOR ME, so obviously is only a suggestion. I don't know your DS or his friends, and not to mention this stage was several years ago for me and nearly a different world to today, so what worked for me may be a disaster for you! But if it's an extreme situation (like mine was for a while), then it may call for extreme measures. Only an idea, so ladies please let me and OP know if I'm way off the mark.
Oh those teenage years are hell on earth for all involved, aren't they??