Refrigerant Circuit Components Overview
Refrigerant Circuit Components Overview
• The parts identified with 1) can be serviced or replaced by any workshop. The work procedures identified with 1) can be performed by any workshop. These components and work procedures do not affect the refrigerant circuit.
• Refrigerant circuit components not identified with 1) cannot be serviced or replaced by all workshops. This also applies to all refrigerant hoses and refrigerant lines. Components not identified with 1) can only be serviced or replaced by a workshop that has all the necessary equipment and tools. In these workshops only trained technicians may perform this work. The refrigerant circuit must be drained.
• Service work on the A/C system that requires the refrigerant circuit to be discharged, and thus cannot be performed in every Audi and VW workshop, is described starting in => [ Refrigerant Circuit, Servicing ] Refrigerant Circuit, Servicing.
HD = High-pressure end
ND = Low-pressure end
1 A/C Compressor Regulator Valve (N280)
• Checking activation and function, refer to => [ A/C Compressor Regulator Valve (N280), Checking Switch-On Signal ] A/C Compressor Regulator Valve (N280), Checking Switch-On Signal.
2 A/C Compressor
• Refer to => [ A/C Compressor From Bracket ] A/C Compressor from Bracket.
• For vehicles with 6 cylinder FSI engine or with an 8 cylinder FSI / TFSI engine, the A/C compressor can only be removed from the bracket if the refrigerant circuit has been discharged. Refer to 6 cylinder gasoline => [ Compressor ] Compressor, 8 cylinder FSI => [ Compressor ] Compressor or 8 cylinder TFSI => [ Compressor ] Compressor.
• For vehicles with 12 cylinder FSI engine, the A/C compressor can only be removed from the bracket if the refrigerant circuit has been discharged => [ A/C Compressor from Bracket ] A/C Compressor from Bracket.
• At start of production, A/C compressors manufactured by Denso (type 6 SEU 14) were installed. Compressors from other manufacturers may also be installed at a later time. Refer to Electronic Parts Catalog.
• Depending on time period of production and on engine, compressor construction type may vary. Refer to Electronic Parts Catalog.
• These A/C compressors are available as replacement parts with different oil fill capacities, therefore note capacity on A/C compressor and the exact part number. Refer to Electronic Parts Catalog and => Fluid Capacity Tables.
• Depending on compressor type, different refrigerant oil fill capacities may be designated for the refrigerant circuit. The reason for the different oil capacities in the A/C compressor for an otherwise identical refrigerant circuit lies in the design of the compressor itself, note these oil capacities. Too much oil in the refrigerant circuit increases the pressures and reduces the A/C cooling output. Too little oil can produce lubrication problems in the A/C compressor. Refer to => Fluid Capacity Tables.
• On installing refrigerant pipes and corresponding holder, make sure there is adequate distance between belt, holder and pulley.
• Depending on A/C compressor type and the design of the refrigerant circuit (one or two evaporators), different refrigerant oil and refrigerant capacities are designated for the refrigerant circuit. Refer to => Fluid Capacity Tables.
3 A/C Compressor Belt Pulley /Drive Unit
• Vehicles with 6-cylinder and 12 cylinder engines engine 1) Refer to => [ A/C Compressor Belt Pulley ] Service and Repair
• Vehicles with 12 cylinder, refer to => [ A/C Compressor Belt Pulley - Version 2 ] A/C Compressor Belt Pulley - Version 2 and => [ Belt Pulley From A/C Compressor Version 2 ] Belt Pulley From A/C Compressor Version 2.
• Ribbed belt-allocation. Refer to Electronic Parts Catalog.
• Replace the A/C compressor drive unit, refer to => [ A/C Compressor Drive Unit ] A/C Compressor Drive Unit, 8 cylinder FSI => [ Compressor ] Compressor or 8 cylinder TFSI => [ Compressor ] Compressor.
• There is an overload protection installed between the belt pulley and the A/C compressor input shaft to protect the belt should the A/C compressor get blocked or be difficult to move.
• If the A/C compressor is runs with resistance, the overload safeguard interrupts the supply of power to it.
• Rubber elements are installed between belt pulley/drive unit and the A/C compressor driveshaft, vibrations which may occur during A/C compressor operation may be dissipated via these rubber elements (damper function at torque fluctuations).
• Different versions of the pulley are installed depending on the type of A/C compressor and engine, refer to the Electronic Parts Catalog.
4 Oil Drain Plug
5 Pressure Relief Valve
6 Connection in Refrigerant Line
• Depending on the version of the vehicle and the engine, these connection points may be present at different locations on the refrigerant lines.
• Bolts of the connection points must only be loosened when refrigerant circuit has been discharged.
7 Connection With Valve
8 A/C Pressure/Temperature Sensor (G395) 1)
• Removing and installing, refer to => [ A/C Pressure/Temperature Sensor (G395) ] A/C Pressure/Temperature Sensor (G395).
• To check the signal use the Vehicle Diagnostic Tester in the "Guided Fault Finding" function.
• The A/C pressure/temperature sensor exchanges information with the vehicle electrical system control module (J519) via a local data bus. The vehicle electrical system control module transmits the data via the data bus to the Climatronic control module (J255). A high pressure sensor (G65) cannot be installed on this vehicle (it only delivers square-wave signals). Refer to the Electronic Parts Catalog.
• The temperature measured by the A/C pressure/temperature sensor differs from the actual refrigerant temperature in the refrigerant circuit because of the A/C pressure/temperature sensor design and its component location. Because of this, it is not currently evaluated and is not used to regulate the A/C system.
9 Condenser (With Fluid Reservoir)
• Different versions, refer to the Electronic Parts Catalog.
10 Fluid Reservoir (Of The Condenser With Dryer Cartridge)
• Fluid reservoir is a component of the condenser.
• The dryer cartridge can be replaced as an individual part. Refer to => [ Dryer Cartridge ] Dryer Cartridge.
• Different versions, refer to the Electronic Parts Catalog.
• The dryer cartridge may be removed only when the refrigerant circuit is empty.
11 Refrigerant Line Quick-Release Coupling - Low Pressure Side
• Installed in the area under the left headlamp.
The quick-release coupling connectors may be unlocked and opened only if the refrigerant circuit is empty.
12 Refrigerant Line Quick-Release Coupling - High Pressure Side
• Installed in the area under the left headlamp
The quick-release coupling connectors may be unlocked and opened only if the refrigerant circuit is empty.
13 Refrigerant Pipe With Inner Heat Exchanger
• In this refrigerant line, the liquid warm refrigerant flowing on the high pressure side releases energy into the vaporous cold refrigerant flowing on the low pressure side. This increases the cooling efficiency of the A/C system.
14 Refrigerant Line Quick-Release Coupling - Low Pressure Side
• Installed in the area of the A-pillar under the left fender.
The quick-release couplings may be unlocked and opened only if the refrigerant circuit is empty.
15 Refrigerant Line Quick-Release Coupling - High Pressure Side
• Installed in the area of the A-pillar under the left fender.
The quick-release coupling connectors may be unlocked and opened only if the refrigerant circuit is empty.
16 Sealing Cap
• With a seal.
• Always screw on.
17 Low Pressure Side Service Connection
• Different versions (with primary sealing valve or with Schrader valve) depending on refrigerant line, distinguishing characteristics.
• The service connection is installed in the plenum chamber under a door of the plenum chamber cover.
Only remove service connections when the refrigerant circuit is empty. The connection does not have a valve.
18 High Pressure Side Service Connection
• Different versions (with primary sealing valve or with Schrader valve) depending on refrigerant line, distinguishing characteristics.
• The service connection is installed in the plenum chamber under a door of the plenum chamber cover.
Only remove service connections when the refrigerant circuit is empty. The connection does not have a valve.
19 Sealing Cap
• With a seal.
• Always screw on.
20 Front Expansion Valve
• For the evaporator in the front A/C unit (A/C unit installed under the instrument panel, in the plenum chamber).
• Checking function, refer to => [ A/C Unit, Checking Cooling Output ] A/C Unit, Checking Cooling Output.
• After the A/C compressor is switched off in this vehicle, it may take a relatively long time for the pressure on the high pressure side to decrease (the expansion valve(s) is/are cold, the pressure on the low pressure side increases quickly after deactivation, the expansion valve(s) closes/close and the refrigerant can only flow slowly to the low pressure side).
21 Evaporator
• Evaporator in front A/C unit (installed under instrument panel).
22 Connection of Refrigerant Line to Evaporator in Rear Heating and A/C Unit
• Only present on vehicles with a rear heating and A/C unit (optional equipment).
• High pressure side.
• Bolts of the connection points must only be loosened when refrigerant circuit has been discharged.
23 Connection in Refrigerant Line to Evaporator in Rear Heating and A/C Unit
• Only present on vehicles with a rear heating and A/C unit (optional equipment).
• Bolts of the connection points must only be loosened when refrigerant circuit has been discharged.
24 Rear Expansion Valve
• Only present on vehicles with a rear heating and A/C unit (optional equipment).
• For the evaporator in the rear A/C unit (installed on the underbody of the vehicle in the area of the center tunnel).
• Check the function, refer to => [ A/C Unit, Checking Cooling Output ] A/C Unit, Checking Cooling Output.
• After the A/C compressor is switched off in this vehicle, it may take a relatively long time for the pressure on the high pressure side to decrease (the expansion valve(s) is/are cold, the pressure on the low pressure side increases quickly after deactivation, the expansion valve(s) closes/close and the refrigerant can only flow slowly to the low pressure side).
25 Rear Evaporator
• Only present on vehicles with a rear heating and A/C unit (optional equipment).
• Evaporator installed in the rear A/C unit (A/C unit installed in the center console).