To analyze control systems of the engine, figurative scanners are used. All models are equipped with system of onboard diagnostics of OBD-II. This system consists of the board computer called by the control unit by the engine (PCM), and the information sensors supervising various functions of the engine and sending data of PCM. This system includes a number of diagnostic registrars which find malfunctions in system of injection of fuel and a control system паров fuels and store information in memory of the computer. This updated system also checks and diagnoses sensors and clears codes. For connection with the powerful diagnostic computer the 16-contact electric socket of communication of data (DLC) is used. PCM by means of electronics operates fuel system and catching system паров fuels. On the basis of received information from sensors, PCM target signals operates various relays, fuel nozzles both other devices and drives. PCM is adjusted so that to optimize toxicity of the fulfilled gases, to keep dynamic characteristics of the car at economic fuel consumption.