Recreational Vehicle Lpg Tank Valve/gauge problems of the 2016 GMC Yukon

The front collision avoidance system does not work. I can set a 1-3 bar alert on the steering wheel, however in the 3 months I've owned the car and trying different maneuvers at different speeds, I don't get a an audible nor visual red light warning that I've experienced on a newer chevy impala I drive. The dash info center below the gauges will change from a green semi-circular 3 bar system to a yellow if I come within the 3 car lengths set of another vehicle while driving. I've researched this issue using google and quite a few people say different GMC models with this system all behave differently. Everyone uses the you tube video by gm as the example of how it is supposed to work. Note, my windshield next to the rearview mirror is clean, so the sensors are not impeded. To me, setting the system to the maximum forward distance to avoid a collision gives you a false sense of security that could easily lead to an accident. The system does not work as designed.