The Transportation Department says it's seeking the maximum penalty, more than $16 million, against Toyota for failing to promptly notify the government about defective gas pedals among its vehicles.
The fine would be the largest civil penalty ever issued to an automaker by the government.
Transportation Secretary Ray LaHood says evidence shows that Toyota knew of the problem with sticking gas pedals in late September but did not issue a recall until late January.
Toyota has two weeks to accept or contest the $16.375 million penalty.
Toyota has recalled more than 6 million vehicles in the U.S., and more than 8 million worldwide, because of acceleration problems in multiple models and braking issues in the Prius hybrid.
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