Miniaturized semiconductor gas sensor are manufactured using sol - gel and microelectronic technology. The sensitive element consists of a semiconducting metal oxide layer, in particular Titanium oxide layer and the measurement of specific oxidizing or reducing gases are based on reversible conductivity change of the sensing element at an appropriate working temperature.In this paper we test sol-gel TiO2 thin film sensors for automotive applications in order to control and improve the economy, power, vibration, and mainly emission of an internal combustion engine. We compare the commercial lambda probe with thin film TiO2 sensor.