Last month GM announced an airbag recall affecting 4 million vehicles. Software errors have been found to disable the front airbags and seatbelt pretensions after "certain driving conditions." GM won't say what those conditions are, but they did say there’s been at least one death related to the bug.
“GM opened an investigation into the issue in June and contacted Delphi, the supplier of the sensing and diagnostic module. The automaker gathered additional electronic data recorder records from other incidents where the same crash symptoms occurred.”
After three days of road tests in September 2016, GM ordered the recall. The affected GMC vehicles include the Sierra lineup as well as the Yukon.