What do you mean the obd light is on?

OBD lamp is a vehicle-mounted automatic diagnosis system, which is usually displayed on the dashboard in the form of faucet symbol, also known as engine fault lamp. The main function of OBD is to monitor the running state of the engine and detect whether the automobile exhaust exceeds the standard at any time. Once exceeding the standard is detected, OBD will immediately issue a warning. The OBD interface can not only provide the data of various working conditions of the vehicle, but also record the data of each fuel consumption record, battery voltage, air-fuel ratio and so on. When the system fails, the fault light or warning light of the detection engine will light up, and the OBD will also store the fault information in the memory. By reading relevant information through standard diagnostic instruments and interfaces, the nature and location of faults can be determined quickly and accurately.