Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
Refrigerant Circuit, Discharging
- Work procedure may vary depending on the type of tools selected (the tool-specific operating instructions should therefore be followed). Refer to the A/C Service Station Owner's Manual.
- The refrigerant circuit is to be discharged if parts of the refrigerant circuit are to be removed, if there is any doubt about the quantity of refrigerant in the circuit, when contaminated refrigerant is determined by the gas analysis or if safety precautions so require.
- All of the necessary operating instructions for working with the A/C Service Station for refrigerant can be found in the A/C Service Station Owner's Manual. Refer to the A/C Service Station Owner's Manual.
Evacuate
-- On vehicles with high-voltage system, switch on the "parking air conditioner" function (deactivate). Refer to the Owner's Manual.
-- Switch off the ignition.
-- Connect the A/C Service Station to the power supply.
Additionally on vehicles with electric operated valves in the refrigerant circuit, which cannot be opened without power:
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, for example, via stepper motors and after switching off the ignition are no longer activated. To completely discharge, correctly evacuate and charge the refrigerant circuit, no areas may be closed. Therefore these valves must be opened before these procedures. The function is active and may only be ended if the refrigerant circuit has been evacuated or filled with the A/C service station. Refer to SYSTEM OVERVIEW - REFRIGERANT CIRCUIT and in the "Guided Function" function.
-- Using the Vehicle Diagnostic Tester open the electric activated valves, which cannot be opened without power.
All Vehicles
-- Start the A/C Service Station according to the corresponding operating instructions.
-- Remove the closure caps from the refrigerant circuit service connections (refer to the vehicle-specific refrigerant circuit. Refer to SYSTEM OVERVIEW - REFRIGERANT CIRCUIT .
-- Connect the A/C Service Station to the refrigerant circuit. Refer to A/C SERVICE STATION ON REFRIGERANT CIRCUIT, CONNECTING .
-- Perform a gas analysis with the A/C Service Station. Refer to REFRIGERANT GAS ANALYSIS, PERFORMING .
If it is determined by the gas analysis that the refrigerant R1234yf is contaminated, extract the refrigerant from the refrigerant circuit and return it to the gas supplier to be analyzed, processed (or disposed of). Refer to RETURNING CONTAMINATED REFRIGERANT R1234YF FOR ANALYSIS, PROCESSING, OR DISPOSAL .
Fill the refrigerant which is contaminated in a recycling bottle for analysis, processing or disposal for example to return it to the gas supplier. Refer to RETURNING CONTAMINATED REFRIGERANT R1234YF FOR ANALYSIS, PROCESSING, OR DISPOSAL .
-- Discharge the refrigerant circuit using the A/C Service Station according to the operating instructions.
There is a risk of damaging the A/C compressor if the refrigerant circuit is empty.
- Never start the engine with the refrigerant circuit empty.
NO RELATED
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.