The mileage is about 8000km, the vehicle type is E90, and the BMW 320i car equipped with N46 engine. Users reflect: the engine fault lights on the vehicle are lit up, and the engine is powerless. Fault diagnosis: after the vehicle comes to the store, the first diagnostic test is carried out through the ISID, the contents of the read fault are as follows:. 2B28 DME throttle regulator, position monitoring, 2BOB DME throttle potentiometer, 2B22 DME throttle regulator, closed spring detection, 2B06 DME throttle potentiometer, 2B02 DME section valve potentiometer, 2B20 intake throttle regulator In control of the above fault content, the ISTA system does not give a detailed description of the fault, but from the description of the type of fault, some of the faults are found to be present. The fault content execution detection plan is selected, and the following faults are stored for the function or component of the detection: (1) the engine control module: 2B02, the current fault exists. Possible causes of failure: - detection wire and plug connection, main relay, electric throttle regulator, engine control module (2) engine control module: 2B06, the current failure. Possible causes of failure: - detection wire and plug connection, main relay, electric throttle regulator, engine control module (3) engine control module: current failure. Hint: the chain malfunction of other throttle failure. (4) engine control module: 2B22, there is no fault at present. The possible causes of failure: - detection wire and plug connection, electric throttle regulator to perform a few of the above fault content detection plan, carry out the related basic inspection, and finally analyze and judge the throttle failure. Replace throttle valve and carry out self adaption of several valve regulators. In order to balance component tolerance, the engine control module and throttle valve need to be adjusted. At this point, we must teach ourselves in the test of a specified emergency air point (throttle interruption position) in the lower mechanical limit (throttle valve completely closed). The reset spring is also inspected. The task of restoring the spring is to close the throttle in case of failure. The following conditions must be met: the battery voltage > 10V, engine speed < 32r/min, vehicle speed < 2km/h / air inlet temperature > 10 C, engine temperature > 10 C, <142 C in addition to the failure of the throttle potentiometer. At each switch to ignition switch position 2, check the throttle position without power. The throttle must be in an emergency air point at this time. In the emergency air point throttle, a gap is still raised because of the spring force, so that enough air can still be obtained for the emergency operation of the engine when the throttle is closed. If the measured emergency air point is outside the allowable range, there will be a fault storage. When the throttle is opened, and then close, the position of the reset spring can be checked to make the throttle return to the emergency air point. There is also a self-contained fault code. In order to avoid the mechanical limit of the throttle on the lower part when running, we should also learn about this point. If the lower mechanical limit is in the allowable range, there will be one fault storage. If the condition of the adjustment is not met, but once the adjustment has been carried out successfully, the adjustment will be interrupted without fault input. The number of adjustments used here last time is applicable. If the adjustment conditions are not met, and the adjustment has never been carried out successfully (for example, the replacement of the engine control module or the throttle), the adjustment will be interrupted in the case of failure input. The engine is only allowed to run in an emergency operation under all fault conditions, because the throttle function is not ensured. Finally delete fault storage, trial run, troubleshooting.