DIAG button on the car refers to the self-test button of the engine electronic control system. DIAG is the ECU computer diagnostic switch. When the engine fault light and SVS light on the instrument panel are on, ECU can diagnose the fault code through this switch, which is convenient for fault finding and maintenance. Use this button regularly to correct the long-lost system data of the electronic control system and ensure the normal operation of the electronic control system.

The electronic control unit of ECU, also known as driving computer, vehicle computer, etc. In terms of use, it is a microcomputer controller for automobiles, also known as a single chip microcomputer for automobiles. It consists of 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.

The function of the electronic control unit is to calculate, process and judge the information input by the air flowmeter and various sensors according to the programs and data in its memory, and then output 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 a microcomputer, input, output and control circuits. Million car purchase subsidy