A/C Service Station, Connecting For Measuring And Testing
- Work procedure may vary depending on the type of tools selected (the tool-specific operating instructions should therefore be followed).
The work procedure is always to be performed as described in the operating instructions for the A/C service station.
The charging hoses are to be connected as follows to prevent the ingress of air or moisture into the refrigerant circuit:
-- On vehicles with a high-voltage system, switch off (deactivate) the "auxiliary climate control" function. Refer to the appropriate Service Information and the appropriate Infotainment/MMI Operating Information.
-- Switch off the ignition.
-- Connect the A/C service station to the power supply.
-- Remove the closure caps from the service connections or connections with a valve. Refer to Refrigerant Circuit (vehicle-specific repair information).
-- Evacuate the charging hoses if necessary.
-- Connect the quick-release coupling to the refrigerant circuit service connection.
- Do not open the valves on the low or high-pressure side when the engine is running. Otherwise, the A/C compressor or A/C service station could be destroyed by a short circuit between the high and low-pressure sides of the refrigerant circuit if the A/C system is switched on.
-- Only install the hand wheel far enough into the quick-release coupling adapter until the service connection is open. Watch the pressure gauge and do not place too much pressure on the valve.
-- Start the engine and perform the planned tests and measurements.
-- Compare the determined values with the specified measured values. Refer to PRESSURES, CHECKING .
-- Before disconnecting the quick-release coupling, close it by removing the hand wheel.
Vehicles with Only One Service Connection:
Install the A/C Adapter Set - Adapter 9:V.A.G 1785/9 , A/C Adapter Set - Adapter 10 :V.A.G 1785/10 or A/C Adapter Set:V.A.G 1786 onto the connections with the refrigerant circuit valve and bleed the charging hoses while connecting to the adapters (faintly audible escape of refrigerant gas is permitted). Refer to A/C SERVICE STATION, CONNECTING .
-- A valve opener must be installed in the charging hose to open the valve in the valve adapter.
Vehicles with High-Voltage System and A/C System Additional Functions (for Example on Audi Q7 e-tron):
For vehicles with the "heat pump" function and/or "high-voltage battery cooling", high pressure is not at the high pressure side service connection in every A/C system operating condition. Depending on the A/C system operating condition, the refrigerant circuit pressure on the high pressure side can only be measured via the pressure / temperature sensor installed in the refrigerant circuit on these vehicles. Refer to Refrigerant Circuit (vehicle-specific repair information) and use the Vehicle Diagnostic Tester in the "Guided Fault Finding" function.
To check the different functions of these A/C systems
-- Select the respective function ("cooling the vehicle interior", "heat pump operation" or "cooling the high-voltage battery") using the Vehicle Diagnostic Tester and perform it according to the specifications using the Vehicle Diagnostic Tester in the "Guided Fault Finding" function.
-- Select and read out the measured values of the different pressure/temperature sensors installed in the refrigerant circuit. Use the Vehicle Diagnostic Tester in the "Guided Fault Finding" function.