Illegal. ECU is an electronic control unit, whose function is to stop calculating, processing and judging the information output by the air flowmeter and various sensors according to the sequence and data in its memory, and then input instructions to provide electric pulse signals with a certain width to the fuel injector to control the fuel injection quantity. The electronic control unit consists of microcomputer, output, input and control circuits. Of course, brushing the car ECU will upset the balance of the car. The manufacturer has reservations about the performance of the engine to ensure the balance of the car. The adjustment in equilibrium state is based on the complex comprehensive value of engine service life and road conditions. Therefore, if one-sided pursuit of power, brakes, shock absorbers and other systems will reach a new balance, which is easy to cause damage to the car. Therefore, it is illegal to brush the car ECU, and it is best not to brush it. ECU electronic control unit, also known as "driving computer". As one of the core components of modern automobile electronics, there may be multiple ECU electronic control units in the automobile, each unit manages different functions, and there is information exchange between ECU systems. Although the control system on the vehicle is becoming more and more complex, it must still have the most basic structure, including microprocessor (CPU), memory (ROM, RAM), input/output interface (I/O), analog-to-digital converter (A/D) and large-scale integrated circuits such as shaping and driving. It is also easy to recognize from the appearance-there is a square box-shaped control element in the engine electronic fuel injection system, which is ECU. There are many slots around the component to connect many input and output circuits. Together with other electronic control components, it forms the brain and nerve center system of the automobile, and monitors various input data (such as braking and gear shifting). ) and various driving conditions of the car (acceleration, slippage, fuel consumption, etc. ) at any time, and according to the pre-designed program to calculate the information from various sensors. After processing, it sends all parameters to all relevant actuators and executes all parameters. The original ECU is used to control the ignition and fuel injection of the engine, so it is an engine control unit in a narrow sense. In the future, more and more electronic systems will be developed for automobiles, including systems for controlling chassis (ESP, ABS, ASR) and systems for controlling transmission (TCU of automatic transmission). So later these control units are collectively referred to as electronic control units, that is, ECU in a broad sense.