What is the function of overdrive/od button in car - toyota vitz/platz/yaris/echo od function

About Toyota Vitz

The Toyota Vitz is a subcompact car produced by the Japanese automobile manufacturer Toyota from 1999 to 2019 in a three- or five-door hatchback body styles. The "Vitz" nameplate was used consistently in Japan, while most international markets received the same vehicle as the Toyota Yaris, or as the Toyota Echo in some markets for the first generation. The Vitz was available in Japan from Toyota's Netz Store dealerships. Toyota began production in Japan and later assembled the vehicle in other ...