Federal safety officials have opened a preliminary investigation into the brakes on an estimated 90,000 BMW 328i models.
The National Highway Traffic Safety Administration is looking at the vehicles, all from the 2013 model year, after receiving four complaints from owners, it said.
Drivers reported feeling a hard brake pedal, increased braking effort and longer stopping distances. Three of the cases were traced by dealers to the vehicles’ vacuum pump, the safety agency said.
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Neither BMW nor NHTSA are aware of any accidents or injuries as a result of this issue. The preliminary investigation "has been opened to assess the scope, frequency and safety-related consequence of the alleged defect," NHTSA said.
"We are cooperating with NHTSA to investigate the issue and we will be providing more information about this in the next few days," said BMW spokesman Julian Arguelles.
No recall of the vehicles is planned at this point.
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