Audi A4 Owners & Service Manuals

Audi A4: Service Station, Important Usage Information

Observe the following with regard to service station operation. Refer to the Parts Catalog (Tools; Special Tools and Equipment: A/C and Heating).

- The filters and dryers installed must be replaced at the latest on completion of the service life specified in the relevant operating instructions.

- If a service station is also used for cleaning (flushing) the refrigerant circuit, dryer and filter must be replaced in shorter intervals. Refer to → Chapter "Refrigerant Circuit, Flushing with Compressed Air and Nitrogen".

- Only refrigerant oils which have been approved for the refrigerant circuit in that vehicle may be added (if necessary, fill refrigerant oil directly into refrigerant circuit). Refer to the Parts Catalog.

Extracted refrigerant is not to be reused if there is any doubt about the composition of the refrigerant extracted, even after cleaning in the service station.

- The service station is to be drained in all these cases. Refer to → Chapter "A/C Service Station, Connecting"). The system is cleaned if necessary and the filters, dryers and refrigerant oil are replaced.

- For example, within Germany, contaminated refrigerant can be returned to the supplier in recycling containers for recycling or for environmentally safe disposal. Other or additional regulations may apply in other countries.

Commercially available service stations can be classified in two groups:

  • Service stations which clean extracted refrigerant for use (so-called extraction and recycling stations for currently available service stations). Refer to the Parts Catalog (Tools; Special Tools and Equipment: A/C and Heating).
  • Service stations which transfer extracted refrigerant to recycling containers (for large-scale recycling). These are referred to as extraction systems.

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:

- Turn off the ignition.

- Connect the service station to the power supply.

- Remove the caps from the service connections or connections with valve. Refer to → Heating, Ventilation and Air Conditioning; Rep. Gr.87; System Overview - Refrigerant Circuit (vehicle-specific repair manual).

- Evacuate the charging hoses if necessary.

- Connect the quick-release coupling to the refrigerant circuit service connection.


Never open valves on low or high-pressure side with the engine running. Otherwise, compressor or service station could be destroyed by a short circuit between high and low-pressure sides of refrigerant circuit if air conditioning system is switched on.

- Only tighten the handwheel in the quick-release coupling just enough so 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 values determined to specified measured values. Refer to → Chapter "Pressures, Checking".

- Before disconnecting the quick-release coupling, close it by screwing out the hand wheel.

Vehicles with Only One Service Connection:


Install the A/C Adapter Set - Adapter 9 -VAG1785/9-, A/C Adapter Set - Adapter 10 -VAG1785/10- or A/C Adapter Set -VAG1786- 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 → Chapter "A/C Service Station, Connecting".

- The charging hose must be installed with a valve opener for opening valve in valve adapter.

On vehicles with high-voltage system and additional functions of the A/C system (for example on Audi Q7 e-tron):


On vehicles with the "heat pump" function and/or "high-voltage battery cooling" in not all operating conditions is the A/C system high pressure on the service connection of the high pressure side. The refrigerant circuit pressure on the high pressure side can on these vehicles depending on the operating conditions of the A/C system, can only be measured via the pressure/temperature sensor installed in the refrigerant circuit. Refer to → Heating, Ventilation and Air Conditioning; Rep. Gr.87; Refrigerant Circuit; System Overview - Refrigerant Circuit 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") via the Vehicle Diagnostic Tester and perform the respective specifications using the Vehicle Diagnostic Tester in the "Guided Fault Finding" function.

- Select the measured values of the different pressure/temperature sensor installed in the refrigerant circuit and read out. Use the Vehicle Diagnostic Tester in the "Guided Fault Finding" function.


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