How normal is the vacuum pumping pressure of automobile air conditioner?

When the automobile air conditioner is running, the normal numerical high pressure is1.3-1.7 MPa (13-17 bar) and the low pressure is 0.1-0.25 MPa (1-2.5 bar). Possible faults of refrigeration system: 1. When the pressure gauge of automobile air conditioner shows low pressure, it may be a common phenomenon of insufficient refrigerant. Some cars will leak refrigerant after a long time of use, and adding refrigerant directly after troubleshooting can solve the problem. 2. When the pressure gauge of automobile air conditioner shows high pressure and low pressure, the expansion valve may be normally open. The car is not well cooled. It is found that both low pressure and high pressure are very high. It may be that the expansion valve is normally open, which leads to the mixing of high and low pressure air in the refrigeration system and makes the refrigeration effect of the air conditioner worse. Replacing expansion valve can solve the problem. 3. When the automobile air conditioner pressure gauge shows low-pressure vacuum (the pointer is below 0 scale) and the high pressure is low, the expansion valve may be closed. The general failure of cars without refrigeration is that the expansion valve of evaporator is closed and needs to be replaced. 4. Sometimes the low pressure gauge is normal, sometimes the vacuum high pressure gauge is normal, and sometimes it is low: when the automobile air conditioning pressure gauge shows that the low pressure gauge is normal, sometimes the vacuum high pressure gauge is normal, and sometimes it is low, which may be that there is moisture in the refrigeration system. When the water in the pipeline freezes, it will lead to vacuum in the low-pressure pipeline. When the system is normal after freezing, only the refrigerant in the system can be released and vacuumized again.