We had a problem with the park assist system not working and went to Van GMC for what we thought was a warranty issue. They told us that one front bumper sensor was damaged and it looked like someone bumped into it and it was not covered by warranty. To get this very expensive sensor changed took 3 days and $530
As a reference, the year 2013 Yukon sensor cost $35 on amazon and is probably the same sensor. A total rip off.....