2. Start the vehicle to turn on the

2. Start the vehicle to turn on the automobile air conditioning and read the data stream of the air conditioning system with v.a.s.5051. The test data that can be seen from the diagnostic device can be seen from the test results that the results of "air conditioning ready" and "AC input" are "air conditioning high gear", indicating that the engine control unit J255 can receive the request signal of air conditioning AC switch; "Compressor condition" is "on", indicating that the engine control unit J255, after collecting relevant sensor data, considers it to be in line with the working conditions of the air conditioning system, so as to improve the engine idle speed and make the air conditioning compressor in the on state. However, the air conditioning system pressure of 750kPa is not up to standard. For tiguan cars, when the air conditioning system is working normally, the high pressure is generally above 1.1mpa, and the current measurement result is 750kPa, which is obviously too low. The pressure is too low to meet the minimum requirement for refrigeration in an air-conditioning system. After the above analysis, data streams of other groups are read,