The National Highway Traffic Safety Administration (NHTSA) has recently opened an investigation into 508 complaints that the power assisted steering can suddenly fail on Ford Fusion, Lincoln MKZ from 2010 through 2012, and 2010 and 2011 Mercury Milan, including gas-electric hybrid versions of the cars.

Drivers Complain Ford Response Inadequate

Although Ford says it is cooperating with NHTSA’s probe and asks anyone experiencing problems to contact their dealer, drivers complained that dealers couldn’t reproduce the problem, and they were left to drive an un-repaired car. Other effected vehicles were out of warranty and the repair cost was $1,400 to $1,900.

Class Action Suit Filed

A class-action suit filed in June 2014 in San Jose, California adds more Ford models to the list, including the compact Focus, alleging that Ford has received hundreds of complaints about the systems, yet it hasn’t disclosed to owners that the systems can fail. The lawsuit states “As a result, drivers of the defective vehicles experience markedly increased steering effort, leaving them unable to control their vehicles.”

NHTSA is monitoring the issue closely, urging all owners with a potential safety defect to contact NHTSA directly. The agency says that drivers reported seeing a warning message appear as the failure happened, but restarting the car did not always correct the problem. NHTSA says it will check the scope and frequency of reported problems, and may seek a recall.