A little more than a week after Ford announced a formal recall of more than 850,000 midsize sedans, the National Highway Traffic Safety Administration formally launched an investigation into another estimated 938,000 late-model vehicles from the Blue Oval.

The investigation is connected with the Ford Fusion and Lincoln MKZ from the 2010 through 2012 model years and the Mercury Milan from the 2010 and 2011 model years.

NHTSA officials said the electric power assisted steering (EPAS) can suddenly fail while driving, resulting in increased steering effort.

The Office of Defects Investigation (ODI) identified 508 complaints alleging loss of power steering assist and increased steering effort. Officials indicated four of these complaints allege that the steering assist failure resulted in increased steering efforts that contributed to a loss of control and crash.

In addition, ODI said it now has related information in early warning reporting field report data submitted by Ford.

“Many of the complaints indicated observing a power steering warning message as the failure occurred,” federal officials said. “In some cases, the condition was corrected by turning the vehicle off and restarting. However, many reports indicate the condition returned again after restart.

“A preliminary evaluation has been opened to assess the scope, frequency and safety consequences of the alleged defect,” they added.

The investigation arrived on the heels of Ford recalling 850,000 vehicles because of potential issues with the restraints control module that could prevent the airbags from functioning correctly.

And this NHTSA investigation announcement also arrived not longer after officials said they were looking into nearly 5 million trucks, SUVs and vans manufactured by Chrysler Group.