What is the fault when the car air conditioner has high low pressure and low high pressure?

[Nevaeh]

The possible causes could be lack of refrigerant, or blockage in the expansion valve or dryer. Here is some extended information: 1. Under normal circumstances, when the compressor is running at 1500-2000 rpm, the high pressure should be around 1.5-2.0 MPa, while the low pressure should be around 0.15-0.35 MPa. 2. If the ambient temperature around the vehicle is high, the high pressure may reach around 2.5-2.8 MPa, but it generally should not exceed 3.1 MPa. Otherwise, the pressure protection will be triggered (to ensure the safe operation of the air conditioning compressor, most vehicle air conditioning systems are equipped with a pressure protection switch. When the air conditioning system pressure is too high or too low, the air conditioning pressure switch will be triggered and stop the compressor). 3. When the car air conditioner shows low low pressure and normal high pressure, excluding naturally cold weather conditions, it is usually caused by a malfunction or failure of the air conditioning compressor.