For 1990-2009 cars

The compressor is equipped with a pressure relief valve. The pressure relief valve is placed in the system as a safety factor. Under certain conditions, the refrigerant on the discharge side may exceed the designed operating pressure. The valve is designed to open automatically at approximately 3036 kPa (455 to 525 psi) in order to prevent system damage. Correct any condition that causes this valve to open. Replace any expelled refrigerant oil. Inspect the air conditioning refrigerant pressure sensor for the proper calibration.