A/C System, Operating After Charging
If the mechanically driven A/C compressor was removed, rotate it approximately 10 times by hand before using it for the first time (during or after installing, for example before installing the belt) to prevent damage caused by liquid impact when first switched on (any oil in A/C compressor cylinder is forced out on rotation).
If the electronically driven A/C compressor was removed, activate it after charging the A/C compressor via the "Basic setting, compressor cut-in" function for the Guided Fault Finding before switching on the A/C system. Refer to Vehicle Diagnostic Tester in the Guided Fault Finding Function for A/C System and Battery Regulation. This prevents the A/C compressor from being damaged, for example, by liquid impact when it is first switched on (any oil in the A/C compressor compression chamber is forced out).
The engine drives the mechanically driven A/C compressor via a belt or shaft. The electronically driven A/C compressor is driven via an electric motor attached directly to the A/C compressor (for example on hybrid vehicles).
A/C System, Operating with Mechanically Driven A/C Compressor
-- Start the engine with the A/C compressor switched off (version with A/C clutch).
-- Set the A/C compressor to minimum output, for example, "Econ" or A/C off mode (version with no A/C clutch with regulator valve).
-- Wait until idle speed has stabilized.
-- Switch on the A/C compressor and operate the system for at least two minutes at idle speed.
-- If necessary, check the pressures in the refrigerant circuit using the A/C service station.
-- Turn off the engine.
-- Remove the hand wheel on the quick-release coupling adapter.
-- Disconnect the charging hoses from the refrigerant circuit.
-- Re-install the closure caps.
A/C System, Operating with Electrically Driven A/C Compressor
-- Operate the A/C compressor using the "Basic setting, compressor cut-in" function in Guided Fault Finding. Refer to Vehicle Diagnostic Tester in Guided Fault Finding function for A/C System and Battery Regulation.
Also for vehicles with electrically operated valves in the refrigerant circuit that cannot be opened without current (for example the Audi Q7 e-tron):
-- The Vehicle Diagnostic Tester enables the activation of the electrically activated valves (not open without current) for A/C system operation via the respective control module (to open or close). Use the Vehicle Diagnostic Tester in the "Guided Fault Finding" function.
For vehicles with a high-voltage system and additional A/C system functions ("heat pump operation" or "cooling the high-voltage battery"), valves may be installed in the refrigerant circuit that cannot be opened without current. These valves are opened and closed via stepper motors, for example, and are no longer activated after switching off the ignition. To completely discharge, correctly evacuate and charge the refrigerant circuit, no areas may be closed. Therefore these valves must be opened before these procedures. After completing the work on the refrigerant circuit, use the respective control module to re-activate the triggering of the valves, which are controlled by stepper motors, for example. Refer to Refrigerant Circuit (vehicle-specific service information) and use the Vehicle Diagnostic Tester in the "Guided Fault Finding" function.
All
-- After the basic setting and if necessary, check the pressures in the refrigerant circuit using the A/C service station. Refer to Refer to A/C SERVICE STATION, CONNECTING FOR MEASURING AND TESTING .
-- Remove the hand wheel on the quick-release coupling adapter.
-- Disconnect the charging hoses from the refrigerant circuit.
-- Re-install the closure caps.