Possible Deviation from Specified Value During the Pressure Test (7 Of 11)

WARNING: This page is about a different car, the 2023 Audi SQ8, 2023 Audi RS Q8, and 2023 Audi Q8. However, it is still accessible from the selected car via links, so may be relevant.

Possible deviation from specified value during the pressure test
The required cooling output is not attained in the heater and A/C unit evaporator (and in the evaporator for battery cooling). The high pressure pipe corresponds to the specified value Low pressure quickly drops to specified value or lower.
Possible causes for the deviation from specified value and their solutions
A/C compressor activation or functionality malfunctioning. Constriction or obstruction in refrigerant circuit. -- Check the activation and function of the A/C compressor and service. Use the Vehicle Diagnostic Tester in the "Guided Fault Finding" function of the A/C system and the battery regulation. If not error can be determined run hand over refrigerant circuit to check for differences in temperature. Refer to Refrigerant Circuit (vehicle-specific service information).-- If difference in temperature is found at one component: If the hose or pipe is kinked or constricted, replace this component. Refer to Refrigerant Circuit (vehicle-specific service information). If there is a blockage clean the refrigerant circuit (flush with refrigerant R1234yf). Refer to REFRIGERANT CIRCUIT, CLEANING . There is too little refrigerant in the refrigerant circuit. -- Extract refrigerant from the refrigerant circuit. Refer to REFRIGERANT CIRCUIT, DISCHARGING .-- If the extracted refrigerant quantity is significantly less than the specified capacity (more that 100 g (3.5 oz)). Refer to Technical Data (vehicle-specific service information), and look for leaks and correct. Refer to LEAKS, FINDING .-- If the extracted refrigerant quantity corresponds to the capacity or is only slightly smaller (maximum 100 g (3.5 oz)). (refer to Technical Data (vehicle-specific service information)) check the expansion valve and shut-off valve for function. Refer to Refrigerant Circuit (vehicle-specific service information). The expansion valve for the evaporator in the heater and A/C unit is faulty. Refer to Refrigerant Circuit (vehicle-specific service information). A Refrigerant Shut-Off Valve -- is faulty (closed). Use the Vehicle Diagnostic Tester in the "Guided Fault Finding" function for the A/C system and the battery regulation and refer to Refrigerant Circuit (vehicle-specific service information). -- If equipped, check the function of the installed shut-off valve. Refer to Refrigerant Circuit (vehicle-specific service information).-- Replace the expansion valve for the evaporator in the heater and A/C unit. Refer to Refrigerant Circuit (vehicle-specific service information).
Final Procedures
-- Charge the refrigerant circuit. Refer to REFRIGERANT CIRCUIT, CHARGING .-- Repeat the test. Refer to ELECTRICALLY-DRIVEN A/C COMPRESSOR, CHECKING PRESSURE WITH A/C SYSTEM SWITCHED ON .

NOTE:

Pay attention to the notes to do so. Refer to Possible Deviation from Specified Value During the Pressure Test (1 Of 11) and Possible Deviation from Specified Value During the Pressure Test (5 Of 11) .