General Motors (GM) is recalling 3.16 million more cars in the US because of ignition switch problems, and will change or replace keys on the cars, which date from 2000 to 2014.
Switches can move out of the run position if cars are jarred, and disable power steering.
Last week GM recalled more than 500,000 Chevrolet Camaro cars after finding a fault with its ignition system.
In March, it recalled 2.6 million cars because of a faulty ignition switch.
GM says it is aware of eight crashes and six injuries related to the latest recall.
A company statement said: “If the ignition switch moves out of the ‘run’ position, there is an effect on power steering and power braking.
“In addition, the timing of the key movement out of the ‘run’ position, relative to the activation of the sensing algorithm of the crash event, may result in the air bags not deploying.”
The company has now also raised its expected second-quarter charge for recall expenses to $700m, up from $400m.
In May, the company was fined $35m (£21m) for failing to address defects which have been linked to 13 deaths.
GM has now recalled more than 17 million cars in the US this year – more than the carmaker sold in 2013.
Previous recalls have involved possible faulty seat belts, transmissions and air bags, as well as potential fire issues.
The announcement was made after the close of the New York Stock Exchange, where its shares had ended the day up by 1.21% at $30.06.