The U.S. government is investigating more than 100 complaints of poor brake performance on 2.7 million General Motors big pickups and SUVs.
The National Highway Traffic Safety Administration says a brake vacuum pump can deteriorate, causing increased braking effort and longer stopping distances.
The agency has 111 consumer complaints including nine crashes and two injuries.
The investigation covers 2014 through 2016 Chevrolet Silverado and GMC Sierra pickups. Also involved are Chevrolet Suburban and Tahoe, the GMC Yukon and Cadillac Escalade SUVs.
The agency will determine how often the problem happens and whether a recall is necessary.
GM is monitoring complaints and warranty claims about the brakes and is working with NHTSA to evaluate them, spokesman Tom Wilkinson said Friday.
Any owner who has a problem with brake performance should have them examined by a GM dealer or independent repair shop, Wilkinson said.
They should keep receipts because they could be reimbursed for repairs if there is a recall, he added.
In September, GM recalled more thanin the U.S. because of power-assisted steering problems that have been linked to a number of accidents.
GM said the power steering can fail during a voltage drop and suddenly return, mainly during low-speed turns. Such a failure increases the risk of a crash. At the time of the recall GM had 30 reports of crashes with two injuries, but no deaths.
The recall covered certain 2015 Chevrolet Silverado and GMC Sierra 1500 pickups; Chevy Tahoe and Suburban SUVs; the 2015 Cadillac Escalade; and GMC Yukon SUVs.