The NHTSA reports nine crashes and two injuries related to the issue.

Braking is an essential function for the safe operation of a motor vehicle. Cars need to go, and they need to stop, which is why General Motors will recall nearly 3.5 million trucks and SUVs because of a possible issue with a vacuum pump that could make braking more difficult, according to Reuters. The recall affects 3.46 million 2015-2017 Cadillac Escalade, 2014-2018 Chevy Silverado, 2015-2018 Chevy Suburban, 2015-2018 Chevy Tahoe, 2014-2018 GMC Sierra, and 2015-2018 GMC Yukon vehicles. 

GM discovered the problem and reported it to the National Highway Traffic Safety Administration, according to the report. The NHTSA opened an investigation into the issue last November. Then in July, the federal agency provided the Detroit-based automaker with additional information, which prompted the company to open its own investigation into the issue. The NHTSA links nine crashes and two injuries to the issue. It's not clear if there are more crashes or injuries related to the recall.

The issue revolves around the vacuum assist pump that’s lubricated with engine oil. Oil flows into the pump through a filter screen, but excess oil sludge and other debris could accumulate on the filter screen, reducing the screen’s effectiveness over time while also, possibly, increasing braking effort and braking distance. This increased effort and distance could raise the risk of a crash.

Dealerships will recalibrate the vehicle’s electronic brake control module to remedy the problem. The fix is free of charge, too. This new programming will allow the vehicle, once vacuum assist is gone, to better utilize its hydraulic brake boost assist function. GM says affected trucks and SUVs built before 2014 and after 2018 are not equipped with the affected vacuum pump. According to the NHTSA, GM will notify affected owners; however, the automaker did not provide a timeline as to when that would happen.