General Motors recalled nearly 1.5 million vehicles on Friday including for possible problems with ignitions blamed for 12 deaths.
Last month, GM called back 1.6 million cars amid questions over why it had taken years to address an ignition defect it knew about as early as 2001.
GM said there was no evidence of fatalities from ignition-related incidents in the new group of 824,000 cars being called back -- Chevrolet Cobalts and HHRs, Pontiac Solstices and G5s, and Saturn Skys for 2008-2010 model years.
But it added that 90,000 of the faulty ignitions were in the 2005-2007 models used as replacements in cars covered in the new recall.
GM said it needed to check all of the cars in the new action to see which ones had the potentially faulty replacement ignitions.
"We are taking no chances with safety," GM's chief executive Mary Barra said in a statement.
"Trying to locate several thousand switches in a population of 2.2 million vehicles and distributed to thousands of retailers isn't practical. Out of an abundance of caution, we are recalling the rest of the model years."
GM is under investigation by the US Justice Department and by Congress over its admitted mishandling of the problem with the ignitions, which by one count have caused hundreds of accidents.
Since 2005 GM itself has received hundreds of consumer complaints over the problem, in which a car's ignition could suddenly move into "accessory" or "off" position, cutting off electronic systems including airbags.
In the fatal accidents recorded, front seat airbags did not deploy.
GM is now facing lawsuits over the issue, and earlier this week Senator Richard Blumenthal urged the Justice Department to create a fund for accident victims, arguing that the automaker "criminally deceived" the public.
Blumenthal expressed concern that GM may be shielded from legal responsibility for events prior to its 2009 government-assisted bankruptcy reorganization.
"Given the crucial role the United States government played in creation of the current General Motors Corporation, I believe the federal government has a moral, if not legal, obligation to take all necessary steps to protect innocent consumers," he said.
Late on Friday, GM also separately recalled approximately 490,200 trucks and SUVs over possible problems with a six-speed automatic transmission.
That recall concerns 2014 Chevrolet Silverado 1500 and GMC Sierra 1500 pickups, and 2015 Chevrolet Suburban and Tahoe and GMC Yukon and Yukon XL SUVs.
"GM has determined that these vehicles may have a transmission oil cooler line that is not securely seated in its fitting," the firm said in a statement.
"If the line is not securely seated and transmission oil leaks from the fitting, the oil could contact a hot surface and result in a vehicle fire. GM is aware of three incidents and no injuries."
Separately, the firm also issued a recall covering 172,000 Chevrolet Cruzes sold to customers with 1.4L turbo gasoline engines in the US over a right-front axle half shaft "that can fracture and separate without warning during normal driving."
"If a vehicle with a fractured half shaft is parked on an incline without the parking brake applied, the vehicle could move unexpectedly, resulting in a possible crash or injury to pedestrians," GM said in a statement.