Portable scanners are used to analyze engine management systems. All models are equipped with an OBD-II on-board diagnostic system. This system consists of an on-board computer called the engine control unit (PCM), and information sensors that monitor various engine functions and send data to the PCM. This system includes a series of diagnostic loggers that detect malfunctions in the fuel injection system and the fuel vapor control system and store the information in the computer's memory. This updated system also tests and diagnoses sensors and clears codes. A 16-pin electrical data link connector is used to connect to a powerful diagnostic computer (DLC). The PCM electronically controls the fuel and evaporative emission systems. Based on the information received from the sensors, the PCM controls various relays, fuel injectors and other devices and actuators with output signals. The PCM is tuned in such a way as to optimize the toxicity of exhaust gases, maintain the dynamic performance of the car while economical fuel consumption.