2019 Sierra Front Collision Assist

[Spirit24]

Good afternoon - I am having issues with the front collision alert and braking. I recently purchased a 2019 Sierra 1500 fully loaded, signed up for the 3 months of free Onstar. During the first month 1 set the distance on the FCA 3 car lengths, no problem everything worked like a charm, everything flashed according to the manual, the seat gave its vibrating alerts, hey get this one I had the truck in cruise doing approx 110 kms an hour moved up 3 car lengths behind another vehicle  doing 105 kms and my vehicle adjusted my speed to accommodate his speed. Ok here is where it gets interesting 1 month to the day of my free first month Onstar - when in cruise it would no longer adjust to the car in front of me. I just about drove over top of a car assuming it would slow down, (I know I should not be relying on this) everything else is still working - flashing lights, seat.  So, I go to my dealership to see if I had accidentally turn something off.  Dealership: - did you not receive a manual, Me: ok .. yes,  but I do not understand can you please explain, Dealership: have you tried youtube, Me: no I thought you would have the answers, so I went to the Service department they then said let me have a look came back to me 10 min later and said according to youtube it should be working if not come back mon-fri and our technician will be only to happy to help, ok made an appointment for the tech he comes out and said there is no way to really check if the braking is working, so I went through the spiel again "when following a vehicle the truck adjusted its speed to accommodate the driver in front of me,  I was assuming that it is a precaustion on the Forward Collision Alert and Breaking system, he looked at me and said: your 2019 Sierra's does not have the capability of  "Cruise Control Assistance". I basically said I am not crazy or stupid it worked perfectly. So here I sit with a $75,000.00 vehicle, any ideas would be totally appreciated not sure what to do next, can it be connected to Onstar or was that just co-insidence.

Edited September 8, 2019 by Spirit24

[BringTheRain403]

Forward collision assist is not the same as adaptive cruise control. 2019 vehicles so not have adaptive cruise.

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[BringTheRain403]

The forward collision alerts are based off the speed your going. There's pedestrian avoidance and automatic breaking but once you go over a certain speed this doesn't work...

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[Spirit24]

I know the difference but why was my 2019 Sierra matching the speed of the vehicle in front of me was it forward collision alert and breaking doing this

[BringTheRain403]

I think it was in your mind.

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