"Stop sales does not mean stop driving," said John Hanson of Toyota USA.
The company ordered a halt Tuesday to sales and production of eight Toyota models, including Camry and Corolla sedans, because it said accelerator pedals could become stuck and cause a safety issue.
Toyota said there is no "remedy" to fix the problem and there is no plan to allow owners to return their recently purchased cars for refunds.
The company said owners would be notified once the "fix" was determined and that in the meantime they should continue to drive their cars but be aware of a possible problem with the gas pedal.
"It happens only rarely," said Hanson.
Safety experts say Toyota owners should practice shifting gears to neutral in case their cars experience a runaway condition.
Toyota and its dealers have been flooded with calls from worried and angry owners of the affected models.
The corporate spokesman said it was up to dealers on a "case by case basis" to decide if owners could get replacement cars.
The company's briefing papers for dealers, obtained by Edmunds.com, say the problem appears to be linked to accelerator pedals produced by the CTS company at a facility in Canada.
"Over time, some accelerator pedal mechanisms may become worn," the Toyota document reads. "As a result of this wear combined with certain operating and environmental conditions, friction in the mechanism may increase and intermittently result in the accelerator pedal being hard to depress, slow to return or, in the worst case, stick in a partially open position."
"We take full responsibility for the CTS parts," said Hanson.
A person answering the phone at CTS headquarters in Elkhart, Indiana said the company CEO and chairman, Vinod Khilnani, was too busy preparing the company's quarterly profit report to speak about the problem with its accelerators.
In addition to the stop on sales, Toyota also shut down production of the eight affected models at five factories in Texas, Kentucky, Indiana and Canada.
The Toyota spokesman said all of the "employees should come to work and they will be paid." He said the cars could be assembled so that the accelerator units could be added later once a remedy is found.