Had a '16 Z M7 so same setup here with real new (1K miles) '19 Z. Finally took a trip of only about 200 miles but had chances to engage Cruise few times & ran across something I never experienced in my "16 Z. Long trips (now with back problems) I typically stay in Tour mode just to keep my OLD back happy. In town & around my county roads am almost always in PTM/Sport 2 & DON'T use cruise. Sorry, this will take a while to explain. Was driving in Tour with Cruise on & decided I was fixing to play with another car maybe. Moved to Track, pushed the required center **** twice to enter PTM & WHAT?-Cruise disengaged! It was still in standby (light was white now). I'm like h-m-m? Lots of open 4 lane divided road with little traffic, so I began experimenting with the Cruise function. Could NOT re-engage Cruise while in PTM mode. Took it out of PTM, put in Tour, then Sport, then normal Track & Cruise worked as normal, no disengaging going from one NORMAL mode to another. So-o-o, then put in Tour with Cruise set to speed. Pushed center button on mode control ONCE to turn off T/C-WHOA! Now Cruise control COMPLETELY went away, no light whatever displayed. So I attempted to turn Cruise back on with T/C off & damn!, T/C light went away (back available) & Cruise turned back to standby & could re-engage. I am certain (but old) that never happened with my '16 M7 & like I said I like using PTM mode alot & my back wasn't a problem then so I used PTM in combo with Cruise when on open highway (ready to rumble). So I checked my '19's OM to see if it was discussed but nowhere under Cruise instructions or PTM instructions did I find this, new to me deal, with Cruise plus PTM or T/C turned off. So once more quickly to sum up, entering PTM mode disengaged Cruise but left it in standby (white light on) but unavailable. In ANY mode Tour/Sport/Track outside of PTM, if T/C was turned off , by pushing center button once, Cruise control completely DISAPPEARED (no white standby light even) & if Cruise was turned back on-T/C light went out & was again active, with normal Cruise operation fully available. So to me it appears with less than the full compliment of NANNIES on, no cruise control or it goes away till you make them FULLY available again. I guess GM & big government are trying to protect me (us) from doing UNSAFE stuff. Where's the fun in that? I know some will respond with BS that doesn't happen, but BS it did (does) cause I played with the combinations for a good 1/2 hr. trying bunches of combos. Not earth shattering news but quite interesting to me (maybe only me-). Folks with '16 Zs can chime in if they ABSOLUTELY KNOW what I just described happens/happened on THEM also, & I'll have to concede I don't remember my '16Z behavior as I thought. I really hope some will say "Yeah, that changed in such & such model yr. after '16". Oh well, I was bored so thought I'd post-let the flames begin!

 

Holy.....that hurt my head trying to read that......

 

Bottomline :
you have cruise control set while in tour mode setting while moving along at 70mph “for example”

then while cruising with cruise control on you move the center **** to track mode and it kick the car out of cruise control?

I’ll try that in my 2017 m7 and report back.

 

No, two situations it did that. Only if moved to Track then entered PTM (2 pushes on center ****), or if in one of normal Modes of Tour/Sport/Track & T/C was turned off (one push of center ****). Just putting it in NORMAL TRACK MODE does not disengage CC.