Hyundai has offered to extend or enhance warranties of roughly 400,000 owners in America, after it discovered it had overstated the power output of its vehicles in catalogues, print advertisements and media kits.
The South Korean carmaker said it had discovered 28 cases in which its published horsepower figures were overstated
by up to 9kW (12bhp).
Horsepower was erroneously stated in about 1.3 million Hyundais sold since 1992, affecting various years of virtually every car and truck in the Hyundai lineup in America.
The largest discrepancies include the 2001 and 2002 Santa Fe four-wheel-drive, whose 2.4-liter engine produces 138bhp, 11 fewer than the 149bhp Hyundai claimed.
Some models of the Sonata and XG300 sedans, and the Tiburon sports coupe were also revealed to have double-digit discrepancies.
To soothe consumers, Hyundai officials said it will mail offers of warranty extensions to about 400,000 owners of models whose power shortage exceeds 4 per cent.
Owners of affected models from 2000-2003 can choose one of three options: doubling free roadside assistance coverage to a total of 10 years with unlimited mileage, extending bumper-to-bumper warranty coverage from 5 years or 100,000km to 6 years or 120,000km, or extending powertrain coverage from 10 years or 160,000km to 12 years or 200,0000km. Owners of affected 1999 and older models will receive an additional 5 years of free roadside assistance.
Finnbar O'Neil, chief executive officer of Hyundai Motor America, said the company would move aggressively to reassure owners.
"We're announcing these errors because we want our relations with customers, dealers and the public to be open and honest," he said.
"I think it would be far more damaging to the brand name if we buried this data." Hyundai became aware of the mistakes when a Canadian government agency began questioning the claimed 140bhp horsepower for the Sonata sedan.
An investigation showed that preliminary estimates for horsepower had often been adopted in marketing material but were never corrected when actual performance was measured.
Horsepower claims will be confirmed by top engineers in future, said O'Neil.
