17 BMW 320 turns on the fault light after cleaning the throttle.

The causes of engine fault lights are: poor combustion of mixed gas, sensor problems, maintenance problems and oil quality problems. The condition of your vehicle may be caused by the failure of basic settings after cleaning the throttle or the failure of the throttle position sensor. Because you can't see the real car, you can't accurately judge the fault. I suggest you contact the local 4S shop for inspection and maintenance.

Solution of the fault light coming on after cleaning the throttle: after re-checking the line in the 4S shop, initialize the throttle with the computer to solve the fault. This is because when the throttle position sensor is installed back, the line is not connected properly, or when the throttle valve is not fully returned, the vehicle is started by ignition, resulting in abnormal sensor signal.