A/C System Components Outside Passenger Compartment
A/C System Components Outside Passenger Compartment
1 Outside Air Temperature Sensor (G17)
• To remove, remove top bumper cover or remove bottom bumper cover.
• Reach through between bumper cover and condenser, disconnect electrical connection at Outside Air Temperature Sensor and unclip Outside Air Temperature Sensor from mount in cowl brace.
• Measured value of Outside Air Temperature Sensor is evaluated by Instrument Cluster Control Module (J285) and transmitted via Comfort CAN-Bus system to the Climatronic Control Module (J255). Verify using the Vehicle Diagnosis, Testing and Information System VAS5051 in the "Guided Fault Finding" function.
• When engine is hot, measured value of Outside Air Temperature Sensor may be falsified by heat radiating from the radiator, therefore a, for example, lower measured value is stored for up to 4 hours and is used for the outside temperature displayed in the instrument cluster. Verify using the Vehicle Diagnosis, Testing and Information System VAS5051 in the "Guided Fault Finding" function.
2 Condenser
• Only remove when the refrigerant circuit is empty; bring the vehicle to a workshop with the necessary tools and qualified personnel.
• Different versions. Refer to the Electronic Parts Catalog.
• Refrigerant lines, disconnecting and reconnecting, refer to => [ Condenser Refrigerant Lines, Disconnecting and Connecting ] Condenser Refrigerant Lines, Disconnecting and Connecting.
• Condenser, removing and installing, refer to => [ Condenser ] Condenser.
• Removing and installing dryer cartridge, refer to => [ Dryer Cartridge ] Dryer Cartridge.
3 Fluid Reservoir With Dryer Cartridge
• Fluid reservoir is a component of the condenser.
• Remove the dryer cartridge only when the refrigerant circuit is empty; bring the vehicle to a workshop with the necessary tools and qualified personnel.
• The dryer cartridge can be replaced as an individual part. Refer to the Electronic Parts Catalog.
• Removing and installing dryer cartridge, refer to => [ Dryer Cartridge ] Dryer Cartridge.
4 Coolant Fan (V7) and Coolant Fan Control Module (J293)
• The request to switch on the coolant fan is transmitted to the Engine Control Module (ECM) by the Climatronic Control Module (J255) via the CAN-Bus system. The ECM then actuates the fans or the Coolant Fan Control Module. Verify using Vehicle Diagnosis, Testing and Information System VAS5051 in the "Guided Fault Finding" function.
• The respective ECM switches Coolant Fans (via Coolant Fan Control Module) continuously to the desired output. Verify using Vehicle Diagnosis, Testing and Information System VAS 5051 in "Guided Fault Finding" and => Engine Mechanical 19.
• There are different versions installed depending on the vehicle equipment level. Refer to the Electronic Parts Catalog.
• Check actuation of Coolant Fan by the Climatronic Control Module using the Vehicle Diagnosis, Testing and Information System VAS 5051 in "Guided Fault Finding" function.
5 Plenum Chamber Cover With Fresh Air Intake Grille
6 Air Quality Sensor (G238)
• Function, refer to => [ Air Quality Sensor Function ] Description and Operation.
• Checking, refer to => [ Air Quality Sensor, Checking ] Air Quality Sensor (G238), Checking.
• Removing and installing, refer to => [ Air Quality Sensor ] Air Quality Sensor (G238).
• Air quality sensor is installed only on vehicles with a Comfort version A/C system.
7 Fresh Air Intake Housing For A/C System
• Removing and installing, refer to => [ Fresh Air Intake Housing ] Fresh Air Intake Housing.
8 Expansion Valve
• For evaporator in front heating & A/C unit (installed under instrument panel).
• Only remove when the refrigerant circuit is empty; bring the vehicle to a workshop with the necessary tools and qualified personnel.
• Different versions. Refer to the Electronic Parts Catalog.
• Removing and installing, refer to => [ Front Expansion Valve ] Front Expansion Valve.
• 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).
9 High Pressure Sensor (G65)
• Removing and installing, refer to => [ High Pressure Sensor (G65) ] High Pressure Sensor (G65).
• The measured value from the high pressure sensor is displayed in the "read measured values block" in the Climatronic control module (J255). Refer to => [ High Pressure Sensor, Checking Pressure Signal ] High Pressure Sensor (G65), Checking Pressure Signal and Vehicle Diagnosis, Testing and Information System VAS 5051 in "Guided Fault Finding".
• Checking function, signal, refer to => [ High Pressure Sensor, Checking Pressure Signal ] High Pressure Sensor (G65), Checking Pressure Signal.
10 Heated Windshield (Z2)
• Not applicable at this time (introduction as optional equipment not yet finalized).
11 Plenum Chamber Water Drain
• Checking, cleaning, removing and installing, refer to => [ Plenum Chamber Water Drain, Checking And Cleaning ] Procedures.
• One water drain each on left and right sides in plenum chamber, refer to => [ Plenum Chamber Water Drain, Checking And Cleaning ] Procedures.
12 Sunroof With Solar Cells
• Not applicable at this time (introduction as optional equipment not yet finalized).
13 Label
• Indicates type of refrigerant and intended capacity.
14 Forced Air Extractor
• Installed at left and right under rear bumper, refer to => [ Vent Frame, Checking ] Vent Frame, Checking.
• Sealing lips of vent frame must move freely and close automatically.
• In order for the vehicle interior ventilation to function properly, the air ducts that run through the luggage compartment trim must be unobstructed, checking, refer to => [ Vent Frame, Checking ] Vent Frame, Checking.
15 Service Connections
• High-pressure and low-pressure sides.
• Cap with seal; always to be screwed on.
16 Coolant Pump (V50)
• Check the function, refer to => [ Heating Performance Of A/C System, Checking ] Heating Performance Of A/C System, Checking.
• Removing and installing, refer to => [ Coolant Pump (V50) ] Service and Repair.
• Not always installed on the 6 cylinder gasoline vehicles (installed only on vehicles equipped with an auxiliary heater).
17 Coolant Pump (V36)
• Only installed on vehicles with 6 cylinder gasoline engine.
• Check the function, refer to => [ Heating Performance Of A/C System, Checking ] Heating Performance Of A/C System, Checking
• Coolant Pump (V36) is currently installed at rear on the engine (between cylinder head and plenum chamber front wall).
18 End Of Refrigerant Lines To Evaporator In Rear Heating & A/C Unit
• Bolts of the connection points must only be loosened when refrigerant circuit has been discharged.
• Only present in vehicles with a rear A/C unit (optional equipment).
• Loosening connection points of refrigerant lines, refer to => [ Refrigerant Line Connection Points, Loosening and Assembling ] Refrigerant Line Connection Points, Loosening and Assembling.
• Routing of refrigerant lines to evaporator in rear heating & A/C unit, refer to => [ Incorporation of Rear HVAC System Into Cooling and Refrigerant Circuit ] Incorporation of Rear HVAC System Into Cooling and Refrigerant Circuit.
19 Refrigerant Temperature Sensor (G454)
• The connection on which Refrigerant Temperature Sensor is installed does not possess a valve, therefore Refrigerant Temperature Sensor must only be removed with a discharged refrigerant circuit.
• Function and signal utilization, refer to => [ Refrigerant Temperature Sensor (G454), Function and Signal Utilization ] Refrigerant Temperature Sensor (G454), Function and Signal Utilization.
• Not installed in all vehicles (depends on the engine, the version of the vehicle and when the vehicle was produced).
• Removing and installing, refer to => [ Refrigerant Temperature Sensor ] Refrigerant Temperature Sensor (G454).
• For example, installed in vehicles with a 6 cylinder TDI engine or an 8 cylinder engine through 10.2007.
• The refrigerant temperature sensor was discontinued as of November 2007 as a running change. On vehicles with the Comfort A/C system, make sure the Climatronic control module (J255) for the Comfort A/C system is installed. Vehicles with a 6 cylinder TDI engine or an 8 cylinder engine but without a refrigerant temperature sensor may only have the Comfort front control and display unit installed (part number 4L0 820 043, beginning with index letter K). Refer to the Electronic Parts Catalog.
• If the vehicle has the Basis A/C system without a refrigerant temperature sensor, and the sensor is being displayed as a fault, then perform an adaptation to the Basis front A/C control head. It is not necessary to perform this on the Comfort A/C system because it has different versions of the front A/C control head. On vehicles wit the Basis A/C system, "Guided Fault Finding" displays the fault missing refrigerant temperature sensor and the evaluating of the refrigerant temperature sensor switches off (by entering "adaptation"). Verify using Vehicle Diagnosis, Testing and Information System VAS 5051 in "Guided Fault Finding.
20 A/C Compressor Regulator Valve (N280)
• For checking activation and functionality, refer to => [ A/C Compressor Regulator Valve, Checking Activation Signal ] A/C Compressor Regulator Valve (N280), Checking Activation Signal.
21 Compressor
• Removing the A/C compressor from the bracket and installing it again (vehicles with a 6 cylinder engine), refer to => [ Compressor, Removing and Installing on Bracket ] Compressor, Removing and Installing on Bracket.
• Replace the belt pulley, refer to => [ Compressor Belt Pulley ] Compressor Belt Pulley.
• Removing the A/C compressor from the bracket and installing it again (on an 8 cylinder FSI engine), refer to => [ Compressor ] Compressor.
• On an 8 cylinder, it is necessary to evacuate the refrigerant circuit in order to remove the A/C compressor from the bracket. Refer to => [ Compressor ] Compressor.
• Removing and installing the compressor drive unit (an 8 cylinder FSI engine), refer to => [ Compressor Drive Unit ] Description and Operation.
• When installing refrigerant lines/hoses and pertaining bracket, make sure there is a sufficient gap between belt, bracket and belt pulley.
• Refrigerant line, disconnecting from compressor and connecting, refer to => [ Compressor Refrigerant Lines, Disconnecting and Connecting ] Compressor Refrigerant Lines, Disconnecting and Connecting.
• Compressor, removing and installing, refer to => [ Compressor ] Compressor.
• Depending on time period of production and on engine, compressor construction type may vary. Refer to the Electronic Parts Catalog.
• At beginning of production, Denso compressors were installed.
• These compressors are available as replacement parts with differing oil fill capacities, therefore note the oil quantity in the compressor and the exact part number. Refer to the Electronic Parts Catalog. The reason for the different oil quantities in the compressor with an otherwise identical refrigerant circuit lies within the design of the compressor itself, note these oil capacities. Too much oil in the circuit leads to higher pressures and reduces cooling performance of the system. Too little oil may lead to lubrication problems in the compressor.
• Depending on compressor type and design of refrigerant circuit (one or two evaporators), different refrigerant oil capacities are designated for the refrigerant circuit.
• Depending on the design (one or two evaporators), different refrigerant R134a capacities are designated for the refrigerant circuit.