Motor vehicles are the largest source of toxic air pollutants, such as smog. Modern engines can be more “clean”, due to technological progress and the techniques used to control exhaust emissions, but the pollutant emissions will be reduced only when they operate smoothly. When an engine does not operate correctly, the engine’s performance is reduced, combustion is incomplete and the exhaust emissions increase dramatically. There is also a question of vehicle safety, especially at high speeds. A check up can detect possible errors. Many of these errors are not easy to identify because they come from the electrical system. In our garage the repair of such mismatches can be identified and fixed on time.