UPDATE 4-Toyota broadens massive U.S. safety recall

* Recall covers 2.3 mln Toyota brand vehicles

* Action separate from ongoing 4.2 mln vehicle recall

* Toyota says accelerator pedals may be faulty

* Shares down 3.2 pct; analyst shrugs off impact (Adds Toyota comment on Europe)

By David Bailey and Kevin Krolicki

DETROIT, Jan 21 (Reuters) - Toyota Motor Corp (7203.T) said on Thursday it will recall millions more vehicles in the United States, its second massive recall in four months, this time to fix potentially faulty accelerator pedals.

The newest recall, affecting 2.3 million vehicles, marked an acknowledgment that potential problems with dangerous acceleration on Toyota vehicles run deeper than the automaker had first announced and broadened a recall that already ranked as its largest ever.

The recalls have damaged Toyota's reputation for market-leading quality and safety at a time when the automaker's U.S. sales remain under pressure.

Toyota had previously maintained that there was no evidence of a mechanical fault linked to reports of unintended acceleration that prompted the recall of about 4.2 million vehicles last year.

The automaker said the recall announced on Thursday was separate from the earlier action, which Toyota said was aimed at addressing the risk that the accelerator pedals could become entrapped by loose or improperly installed floor mats.

About 1.7 million vehicles are subject to both recalls.

Shares of the world's No.1 carmaker fell 3.2 percent to 4,055 yen on Friday, underperforming the Nikkei stock average's 2.6 percent drop. An analyst, however, shrugged off the impact of the recall.

"The recall is not a completely new development after the previous recall related to the floor mats, nor is it based on any accident," said Eiji Hakomori, an analyst at Daiwa Securities Capital Markets.

The latest recall includes the 2009 and 2010 RAV4; the 2009 and 2010 Corolla; the 2009 and 2010 Matrix; the 2005 to 2010 Avalon; the 2007 to 2010 Camry; the 2010 Highlander; the 2007 to 2010 Tundra; and the 2008 to 2010 Sequoia.

A Toyota spokesman in Tokyo said the company would consider whether it needs to issue a recall in Europe as well, where the same parts are used for some models. Cars sold in Japan do not use the parts in question.

NOT SUDDEN ONSET

Toyota said its own investigation in recent months had found that some accelerator pedals on those Toyota brand models might stick in a partially depressed position or return slowly to idle. The problems could occur when the pedal mechanism becomes worn, it said.

"It isn't a sudden onset issue," Toyota spokesman Brian Lyons said. "The owner would notice that the vehicle is slowly returning to idle."

Toyota was not aware of any accidents or injuries related to the issue, Lyons said. Toyota filed the recall with the National Highway Traffic Safety Administration Thursday and the investigation was in an early stage, he said.

As recently as November, Bob Carter, Toyota's U.S. brand chief, had said there was "no evidence" to support claims that the reported safety problems could be caused by anything other than loose floor mats interfering with the accelerator pedal.

NHTSA had received reports of 100 incidents at the time of Toyota's first recall. Those reports included 17 crashes and five fatalities possibly linked to floor mats and accelerator pedals in Toyota cars and trucks.

Toyota's earlier recall covers the Camry and Avalon sedans, the Prius hybrid, the Tacoma and Tundra pickup trucks, and the luxury Lexus models IS250, IS350 and ES350.

NHTSA had conducted a similar investigation of floor mats in Toyota vehicles that began in 2007 and resulted in a recall of more than 50,000 cars.

That probe focused on the Lexus ES350 and concluded that grooves in the floor mat could trap the accelerator if the mat was not secured with retaining hooks.

The recall announced last year, which affects only North America, is ongoing. Toyota has started repairs on the ES350s and plans to address the Camry and Avalon next, Lyons said. Those vehicles account for more than half the vehicles subject to that recall, he said.

Toyota plans to reshape the accelerator pedals and floors in the Camry, Avalon and ES350, Lyons said. The automaker also is installing a system that at highway speeds will return the engine to idle and give the brakes precedence if the brake and accelerator pedals are pressed at the same time. (Additional reporting by Yumiko Nishitani and Yoshifumi Takemoto in TOKYO; Editing by Matthew Lewis, Steve Orlofsky and David Dolan)