ACTING in response to continuing complaints that its TT sports car is unstable, Audi of America announced last week that North American owners could have electronic stability systems retrofitted on their 2000-model cars. The company's German parent, Audi A.G., had made a similar offer in Europe on Feb. 4.
The TT Coupe made its debut to great acclaim, with particular praise for its sleek, Bauhaus-inspired design and its $31, 000 base price. The car's luster dimmed in Europe, though, after an unusual number of high-speed crashes. Last fall, Audi announced a voluntary recall to fit the cars with a rear air spoiler, to help hold down the back of the car at speed, and new suspension components to improve handling.
As the number of accidents rose in Europe, including five fatalities, German TT owners complained that this solution was insufficient. The death last month of Peter Hommel, 60, a former East German rally driver, added to the clamor. Soon after, Audi A.G. said it would offer owners the option of adding the stability system, which it calls E.S.P., for the equivalent of $325.
The system uses sensors throughout the car to keep track of speed, direction, acceleration and the angle of the steering wheel. If the car seems on the verge of responding inappropriately - for example, if the tail is about to swing out - the system instantly applies the brake at a single wheel and reduces the speed to bring the car back under control. Available in the United States on only a few sport and luxury cars, stability controls are more common in Europe. DaimlerChrysler added such a system to its Mercedes-Benz A-Class when that small car proved unstable in abrupt lane changes.
Neither Audi of America nor the National Highway Traffic Safety Administration report any American complaints about TT handling problems. Audi said the European fatalities occurred in accidents at speeds exceeding 110 miles an hour; such speeds are not unusual on German autobahns but are extraordinary in North America.
''These all are very unfortunate incidents, '' said Jennifer Garber, a spokeswoman for Audi of America. ''But we believe the problem is related to unique driving conditions in Germany that don't apply here.''
Nonetheless, the company said it thought the wisest course was to make E.S.P. available. ''By offering our North American TT owners the choice of purchasing this newly available option, we confirm Audi's intent to have one product standard worldwide, '' said Len Hunt, vice president of Audi of America.