Toyota Motor Corp said on Thursday it was recalling nearly 2.2 million vehicles over the risk that the accelerator pedal could be trapped by loose or misplaced carpet on the driver's side.

Toyota's decision to recall the vehicles was part of an agreement it made with U.S. regulators, who in return have agreed to close their investigation into the safety crisis that damaged the automaker's reputation.

Although Washington officials recently handed the automaker a huge victory by finding that its electronic throttle systems were not a factor in the recall saga of nearly 8 million vehicles in 2009 and 2010, Thursday's action raises new questions about mechanical and equipment issues.

The latest recall underscored the difficulty Toyota has had in overcoming safety questions.

The reality is there are a continuation of problems that are going to haunt the company until they get to the real root of the issue, said Sean Kane, president of Safety Research & Strategies, Inc.

Since Toyota's huge sudden acceleration recalls of a wide range of models, including its top-selling Camry, the automaker has lost market share and had to resort to discounts to win back American consumers.

Toyota's U.S. market share fell from 17 percent at the end of 2009 to just more than 15 percent in December 2010.

Toyota said its decision to widen its initial recalls stemmed from its ongoing conversations with the National Highway Traffic Safety Administration.

NHTSA's chief, David Strickland, said in a statement that the agency reviewed more than 400,000 pages of documents to determine whether the scope of Toyota recalls was sufficient.

As a result of the agency's review, NHTSA asked Toyota to recall these additional vehicles, and now that the company has done so, our investigation is closed, Strickland said.

As part of the latest move, the automaker added nearly 1.4 million vehicles in the United States to a late 2009 recall of vehicles over the risk that the floormat could pry loose and trap the accelerator pedal.

Spokesman John Hanson said there had been no consumer complaints that spurred that action.

What we're trying to do is make sure we've captured any vehicles that could have a problem like this, Hanson said.

Toyota said it was unaware of any injuries or accidents stemming from these recalls.

The 1.4 million vehicles recalled for the latest floormat issues included 761,000 RAV4 crossovers for the model years 2006 through 2010. It also included 603,000 4Runner crossovers for the model years 2003 through 2009 and about 17,000 Lexus LX 570 vehicles for the model years 2008 through 2011.

Thursday's announcement also included two other recalls of vehicles for different issues that also could trap the accelerator pedal, Hanson said.

They are all very dissimilar in what the cause is, Hanson said. But the effect has to do with any cause of accelerator infringement.

The company also recalled 372,000 RX 330, RX 350 and RX 400H vehicles as well as 397,000 Highlander and Highlander HV vehicles because retention clips that hold down the carpet on the driver's side could come loose after service and affect the accelerator pedal.

Toyota spokesman Brian Lyons said there could be other recalls of RX and Highlander vehicles outside the United States.

Toyota also recalled 20,000 Lexus GS 300 and GS 350 all-wheel drive vehicles to change the shape of a plastic pad embedded in the driver's side floor carpet.

After service if the floor carpet is not replaced correctly, the trim may interfere with the pedal, Toyota said.

The company clinched a victory earlier this month after a U.S. government probe concluded that Toyota's electronics did not cause unintended acceleration.

(Reporting by Deepa Seetharaman and John Crawley, editing by Dave Zimmerman and Matthew Lewis)