Toyota is halting the sale of thousands of new cars after being alerted to padding in a seat heater that doesn't meet flammability standards.

The automaker is going to sideline many of its most popular models equipped with seat heaters anywhere in the supply pipeline -- from the factory to the dealership -- until it can replace the heating units. At the moment, spokesman John Hanson says a recall of affected cars already sold to the public is not anticipated.

Those models being put off sale include Camry, Avalon, Sienna and Tacoma from the 2013 and 2014 model years and Corollas and Tundras from 2014. Only vehicles made in Toyota's U.S. plants and those with heated seats are affected.

The problem was discovered when some of the cars were tested by a South Korean safety agency. They agency conducted the tests because some of the vehicles are exported from the U.S., including to South Korea. The Korean Automotive Test and Research Institute found that the fabric backing material used in the seat heaters did not meet U.S vehicle flammability standards, according to Hanson. It informed Toyota, which, in turn, notified the U.S. National Highway Traffic Safety Administration and ordered the cars not to be sold.

Hanson says Toyota hasn't received a single complaint about fires in seats involving the affected models from anywhere in the world. Thus, he says Toyota doesn't believe a recall is warranted. But he says NHTSA will be making its own decision about how to proceed.

He had no initial count on how many cars are affected, except that it is in the thousands. He says repairs should begin relatively soon.