DETROIT (AP) - The U.S. government's highway safety agency is expanding three investigations for brake and air bag troubles that could affect more than 2.3 million vehicles from Ford, Volkswagen and Nissan.

The expansions by the National Highway Traffic Safety Administration were announced Monday and over the weekend on the agency's website after investigators found more consumer complaints about the problems.

The Ford probe now covers a potential brake problem on just over 1 million Fusion, Mercury Milan and Lincoln MKZ cars from the 2006-2012 model years.

Investigators, meanwhile, are looking into whether a VW airbag recall worked on eight models from 2010-2014.

The probe now covers 1.2 million vehicles.

The agency also is upgrading a probe into about 108,000 Nissan Murano SUVs from 2009 to see if more models are affected.

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