Debuting in September 1992 as a 1993 model, the refreshed LS 400 (designed through 1991) was introduced with more than 50 changes, largely in response to customer and dealer requests.[54] The vehicle received larger disc brakes, wheels, and tires, and adjustments were made to the suspension and power steering systems to improve handling.[55] Stylistic changes included additional body side moldings and a revised grille, along with a greater selection of colors.[55] For the interior, a standard passenger front airbag (first Toyota-built series production car available with passenger front airbag),[56] an external temperature gauge, digital odometer, seat belt pretensioners, and chlorofluorocarbon-free refrigerant were added.[55][57] In 1992, the Celsior introduced the world first GPS navigation system with voice instructions,[58] supplied by Aisin.[59] By 1994, the LS 400's U.S. base price exceeded US$50,000, a figure that had steadily risen since the vehicle's introduction.