Possible Deviation from Specified Value During the Pressure Test (8 Of 11)
WARNING: This page is about a different car, the 2024 Audi SQ7, 2024 Audi Q7, 2023 Audi SQ7, and 2023 Audi Q7. 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 required cooling output is only not attained at the heater and A/C unit evaporator (the cooling output on the evaporator for the cooling output is OK).
- The high pressure only falls slightly (via the pressure with the A/C compressor stopped) or corresponds to the specified value.
- Low pressure quickly drops to target value or lower.
|
| Possible causes for the deviation from specified value and their solutions |
- 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 substantially smaller (more than 100 g (3.5 oz)) than the specified capacity, then refer to
Technical Data
(vehicle-specific service information), search for the leakage and correct it. 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 Valves -- is faulty (closed), check the function. 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) for replacing.
-- 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).
- Constriction or blockage in the refrigerant circuit (for example in the refrigerant line between the "low pressure side" service connection and the A/C compressor). Refer to
Refrigerant Circuit
(vehicle-specific service information).
- Activation of the A/C compressor is malfunctioning. Use the Vehicle Diagnostic Tester
in the "Guided Fault Finding" function for the A/C system and the battery regulation.
-- 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 and replace a faulty expansion valve. 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
.-- If there is a blockage clean the refrigerant circuit (flush with refrigerant R1234yf). Refer to REFRIGERANT CIRCUIT, CLEANING
. Replace the expansion valve for the evaporator in the A/C unit (and for the evaporator for battery cooling) as well as the desiccant bag/dryer cartridge (or receiver/receiver/dryer). Refer to COMPONENTS, REPLACING
and
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 . |