A/C Unit
A/C Unit
Special tools, testers and auxiliary items required
• Hose Clamps, Up to 40 mm diameter (3094)
• Hose Clamps Up to 25 mm diameter (3093)
• Commercial compressed-air gun with rubber end piece
• Cooling system tester (V.A.G 1274) (and corresponding adapter)
• On removal, note bolt lengths and assignment for installation later.
• All cable ties and other wiring harness fasteners released or cut open on removing air conditioner unit are to be re-attached in same position on installation.
Removing
- Move the driver and passenger seats as far back as possible.
- Turn off the ignition.
- Drain the refrigerant circuit.
• Depending on the allocation of the service connection an on the refrigerant line, and on the version of the vehicle, it may be necessary to remove the additional reinforcement on the left suspension strut dome so that the service coupling of the service station can be connected (for example, on the Audi Q5).
With high voltage systems (hybrid vehicles)
Read and follow all of the supplemental warnings for all work performed on vehicles with the high voltage system.
If it is necessary for the following procedure to perform work in the vicinity of high voltage components, perform a visual inspection of the high voltage components and cables for damages.
Risk of unintended engine start
The ignition must be turned off and the ignition key must remain outside of the vehicle when working on vehicles with a high voltage system.
How to handle high voltage cable:
• Do not stand on or place tools on high voltage cables and their components as it may damage the cable insulation.
• Never bend or kink high voltage cables forcefully as it may damage the cable insulation.
• Color-code the round high voltage connector with an external color ring and code them mechanically using the guide- or code tabs. Always make certain that the coding matches when connecting the round connector in order to avoid mechanically damaging the high voltage connector.
There is a risk of electrocution from damaged high voltage components
Observe the following when working around high voltage components and high voltage wires:
• Never work around high voltage components and cables with cutting, deformed, or sharp edged tools, or heat sources such as welding or soldering tools, heated air, and thermal glue.
• Inspect the high voltage components visually before beginning.
• Perform a visual inspection of the electric drive power and control electronics (JX1) , the electro-drive drive motor (V141) , the A/C compressor (V470) and the high voltage lines when working in the engine compartment.
• Perform a visual inspection of the high voltage lines and the cover when working on the underbody.
• Perform a visual inspection of the high voltage lines and the Electrobox with the high voltage system maintenance connector (TW) when working in the luggage compartment.
• Perform a visual inspection on all of the potential equalization cables.
Observe the following items when performing the visual inspection:
• The components do not display any signs of external damage.
• The high voltage cable insulation and the potential equalization cables are not damaged.
• The high voltage cables do not display any abnormal deformations.
• Every high voltage component is marked with a red warning label.
The following procedure requires working on the high voltage system. De-energize the high voltage system.
Disable the high voltage system
Risk of electrocution
Death or serious bodily injury by electric shock.
• People with electric/medical life- and health sustaining devices in or on their person must not perform any work on the high voltage system for safety reasons. Internal pain killer pumps, implanted defibrillators, pacemakers, insulin pumps and hearing aids among others are considered life- and health sustaining devices.
• The high voltage system may only be activated by qualified personnel (Audi high voltage mechanic).
• Make sure that the high voltage system is completely disabled. Assure that the voltage performed exclusively using the Vehicle Diagnosis Tester according to the "Guided Fault Finding".
• The qualified personal (Audi high voltage technician) determines the voltage and secures the system from restarting using the locking cap (T40262). Keep the ignition key and the high voltage system maintenance connector (TW) safely with the qualified personal to secure the system from restarting.
• The qualified personal (Audi high voltage technicians) marks the vehicle by attaching warning labels.
• Disable the high voltage system:
• Connect the vehicle diagnosis tester
• Select the Guided Fault Finding mode
• Using the GO TO button, select the following menu commands
• Functions/Component selection
• Body
• Electrical Equipment
• OBD-capable system
• 8C - Hybrid battery management -J840
• 8C - Hybrid battery management, functions
• 51 - Disable the high voltage system (Rep.Gr. 93)
- Remove the rubber seal - A - and the plenum chamber cover - B - (there are different versions).
- Inspect the high voltage components - D - (the electric drive power and control electronics (JX1) ) and the high voltage cables - E - after removing the plenum chamber cover - B -. Refer to => [ Visual Inspection of High-Voltage Components and Cables for Damage ] Visual Inspection of High-Voltage Components and Cables For Damage.
- Disconnect the ground cable from the battery (A).
- Loosen the power distribution panel - 1 - and move it toward the windshield with the wires.
- Remove the high voltage cables for the electric drive power and control electronics (JX1).
- Cover the electric drive power and control electronics (JX1) and wires to prevent them getting damaged and to protect them from dirt.
• Use clean 20 mm bungs - B -, taken from engine bung set (VAS 6122) , to seal off the connection on the electric drive power and control electronics (JX1) - A -.
• Be careful not to damage any high voltage components - D - or the high voltage cables - E -.
• It may be necessary to remove the cowl panel - C - in order to remove and install the expansion valve.
For vehicles without a high voltage system
- Disconnect the ground cable from the battery (A).
- Remove the plenum chamber cover and/or the cowl panel (there are different versions).
• The battery (A) ground connection is disconnected so that it will not short circuit with the jumper cable post removed - C - and when disconnecting the positive cable to both relays for the Auxiliary Air Heater Heating Element (Z35) - J -.
- Remove the jumper cable post cover - C -.
All vehicles
- On vehicles equipped with auxiliary air heater heating element loosen the positive cable to both relays for the Auxiliary Air Heater Heating Element - J - from the jumper cable post - C -.
- If equipped and necessary, remove the suspension strut dome - B - (for example Audi A5 Coupe, not necessary for example on the Audi Q5).
• The plenum chamber front wall cannot be loosen or removed from the vehicle (there is not enough space available).
• Both coolant hoses are routed to the heat exchanger through the plenum chamber front wall - A -. On these vehicles, loosen the grommet on both coolant hoses and move the plenum chamber front wall to the side (when doing this, the refrigerant circuit must not be opened).
• When loosening the plenum chamber front wall, be careful not to damage the brake booster vacuum line.
- Remove the expansion valve. Refer to => [ Expansion Valve ] Expansion Valve.
• The air conditioner can be removed and installed with the expansion valve still installed. Removing and installing with the expansion valve removed is described here due to the increased space.
• Seal open pipe connections.
• To seal off all open connections on expansion valve, sealing caps from a replacement expansion valve can be used (preventing dirt and moisture from entering the system).
- Remove the expansion valve mounting plate - A - from the refrigerant lines - B - and - C - (so that it does not get lost while removing).
- Coat the inner side of the grommet - D - with grease and remove the supporting ring - E -.
- Loosen the grommet - D - from the plenum chamber rear wall toward the passenger compartment (it is removed and installed with the A/C unit).
- Release pressure in cooling circuit by opening cap on coolant expansion tank.
- Mark the arrangement of coolant hoses - A - (supply to cylinder head) and - B - (return to coolant pump).
• The heater core is designed for a specific coolant flow direction. Therefore, coolant hoses must be connected on the correct sides.
• Bleed the coolant circuit.
- Clamp the coolant hoses - A - and - B - with hose clamps.
- Cover the area beneath connections for coolant hoses - A - and - B - for example with absorbent paper.
- Remove coolant hoses - A - and - B - from connections to A/C unit heater core.
- Insert one section each of hose - A - and - B - on to both connections to heater core.
- Place a container - B - under the other end of the hose - C -.
- Using a compressed air gun - D -, carefully blow coolant out of heater core (into container - B -) via hose - A -.
- Loosen the grommet - H - from the plenum chamber rear wall and remove it from the heat exchanger coolant pipes.
- Remove the glove box, the center console and instrument panel.
• To prevent the instrument panel shell from damage, instrument panel should be placed on a clean work bench which is covered with clean cardboard.
- Remove the air intake housing. Refer to => [ A/C Unit Air Intake Housing ] A/C Unit Air Intake Housing.
- Remove the air guides to the left and right instrument panel vents.
• The air guide channel leading the left instrument panel vent - A - is secured by an expanding clip or a screw - B - onto the instrument panel crossmember - C -; the expanding clip or the screw can only be removed when the outer instrument panel shell is removed.
- Remove the air guides to the instrument panel center vents - C - and to the defrost vent - D -.
- Remove the bolts - A - and - B -.
- Remove the steering column.
- Disconnect the connector from the brake lamp switch (F).
- Loosen the instrument panel cross member - E - from the vehicle and from the A/C unit.
• Except for the left fuse box, do not loosen any other left relay- or control unit brackets from the instrument panel cross member.
- Remove the air guide to the rear center console vent - C - (only on vehicles equipped with the "Comfort" A/C system).
- Loosen the air guide to the rear footwell vents - A - and - B - from the intermediate piece - D - and remove the intermediate piece - D -.
- On vehicles equipped with a Auxiliary Air Heater Heating Element (Z35) loosen the ground connection - A - and disconnect the connector - B -. Refer to => [ Auxiliary Air Heater Heating Element (Z35)/Honey Comb ] Service and Repair.
- Disconnect both condensation water drain hoses from the A/C unit. Refer to => [ Condensation Water Drain Hose ] Condensation Water Drain Hose.
- Disconnect the fuse panel "driver side" on the left side of the instrument panel cross member (central tube) - A - from the instrument panel cross member.
• Since the instrument panel cross member is loosen only from the vehicle (not completely removed), the remaining relay-/fuse carriers and clutch stations must not be removed from the instrument panel cross member
- Loosen all electric connections between the instrument panel cross member and the vehicle on the passenger side - B -.
- Cover the carpet in the area of the center tunnel with a mat - C - (and both seats if not already done).
• The instrument panel cross member must not be completely removed in order to remove the A/C unit; it is enough to disconnect the A/C unit from the vehicle and then to swivel it to the rear and place it on the center tunnel.
- Carefully remove the instrument panel cross member from the vehicle and carefully swivel it (and when doing this not to damage any components) to the passenger side - B - far enough to the rear - arrow - so that the A/C unit can be removed to the right - arrow -.
- Remove the vehicle wiring harness in the area of the instrument panel cross member from the A/C unit.
- Carefully remove the A/C unit from the vehicle (with doing this, do not damage any connections and components still not removed).
- On vehicles equipped with a Auxiliary Air Heater Heating Element (Z35) mark the location of the mounting points - B - (with cable ties on the A/C unit) on the positive cable to both relays for the Auxiliary Air Heater Heating Element - A - (for example with a suitable pin on the cable).
- Disconnect the cable - A - from the A/C unit.
- Remove the remaining vehicle wiring harness mounts (for example with cable ties) on the A/C unit.
- Remove the A/C unit - A - in the direction of the passenger side.
• The wiring harness "air conditioner" is removed together with the A/C unit.
Installing
Installation is carried out in the reverse order while noting the following:
• Before installing, check all gaskets and grommets on the A/C unit for damage and replace if necessary.
- Install the A/C unit - A - and the components also removed with the A/C unit (wiring harness "A/C unit", grommet on the evaporator refrigerant lines, etc.) in the vehicle
- Coat the grommet - D - with grease and install it in the plenum chamber rear wall.
- Install the support ring - E - in the grommet - D -.
- Install the instrument panel cross member (central tube)..
- Install the expansion valve mounting plate - A - to the refrigerant lines - B - and - C -.
- Install the grommet - H - in the plenum chamber rear wall.
- Check the position of the coolant and refrigerant line in both grommets, and if necessary, align the A/C unit so that the lines are not tensioned in the grommets.
- Install the screws - A -.
- Slide the strap - F - all the way to the bracket - H -, then turn it downward (when doing this, the bracket - G - locks the A/C unit to the strap)
- Install the bolts - B -.
- Connect both condensation water drain hoses to the A/C unit. Refer to => [ Condensation Water Drain Hose ] Condensation Water Drain Hose.
• When installing the intermediate piece, - D -, the air guides to the rear footwells - A - and - B - and the air guide to the vent in the rear center console - C - make sure that they fit correctly and are securely connected. If they are not connected tightly, warm or cool air could leak out and influence how the A/C system works (this air will be drawn in by the Interior Temperature Sensor Fan (V42) and the values, measured by the Instrument Panel Interior Temperature Sensor (G56) will deviate from the actual temperature in the passenger compartment.
• The intermediate piece - D - latches on the air outlet openings on the air conditioner. There are slits inside the intermediate piece - D -. If the flap position is incorrect, especially on vehicles with the "Comfort" A/C system, whistling noise can come from these slits. The upper slits are covered with tape during production (running change from February 2009). Refer to => [ Rear Vent Air Guide Slots, Sealing ] Rear Vent Air Guide Slots, Sealing.
- Install the air intake housing. Refer to => [ A/C Unit Air Intake Housing ] A/C Unit Air Intake Housing.
- Install the expansion valve. Refer to => [ Expansion Valve ] Expansion Valve.
- Install the refrigerant line with inner heat exchanger. Refer to => [ Refrigerant Circuit Components ] Refrigerant Circuit Components.
- Make sure the grommet - H - fits correctly in the back of the plenum chamber.
- Properly connect the coolant hoses to the heater core, pay attention to the marking.
A Supply hose from cylinder head
B Return to the coolant pump
- Connect the coolant hose - A - to the heater core coolant pipe (pay attention to the marking) and secure it with the clamp - D -.
- Attach the coolant hose for the heater core - B - onto the coolant pipe - F - just far enough as to not cover the bleed hole - G -.
- Remove the hose clamp from the coolant hose - A -.
- Fill the coolant expansion tank with coolant.
- Carefully force the coolant out of the coolant overflow reservoir into the heater core using, for example, the hand pump from the Cooling System Tester (V.A.G 1274/).
- As soon as the coolant comes out the ventilation hole - G -, install the coolant hose - B - on to the coolant pipe - F - at the marking.
- Secure the coolant hose - B - with the clamp - E - on the marked location.
- Remove the hose clamp from the coolant hose - D -.
- Add more coolant to the coolant reservoir, if necessary.
• This procedure completely bleeds the cooling system. If, for some other reason, there still should be some air in the cooling system, install all the components and bleed the system once again.
Check the connections at the heater corer for leaks as follows:
- Carefully increase the pressure in the coolant circuit by using, for example, the hand pump of the cooling system tester (V.A.G 1274/).
- Check coolant circuit for leaks, pay particular attention to the connection between coolant hoses and heater core Engine Mechanical.
• This illustration shows the coolant pipes on a replacement heater core. The coolant pipes are attached to the heater core by clamps. Refer to => [ Heater Core Removing and Installing ] Heater Core Removing and Installing.
• When bleeding coolant circuit, take special care to ensure complete bleeding of heater cores. If there are still air bubbles in the heater core, it may cause the customer to complain of insufficient heating performance in winter or different air temperature from vents at same setting in regulated mode. Refer to => [ Heat Output and Temperature Door Activation, Checking ] Heat Output and Temperature Door Activation, Checking.
• Depending on vehicle equipment and on engine, heat insulation has been applied to coolant hoses, these must not be damaged and must be re-applied after installing.
- Secure the wiring harness once again on the provided places and install the different air guides in reverse order.
- Install the instrument panel, the center console, and glove box, etc.
• When installing the instrument panel, make sure that the "defrost" intermediate piece its properly on A/C unit and the defrost vent does not pinch the intermediate piece. Refer to => [ Air Routing and Distribution in Passenger Compartment ] Air Routing and Distribution In Passenger Compartment.
With high voltage systems (hybrid vehicles)
- Inspect the high voltage components - D - and high voltage cables - E - after completing the work procedure and before installing the plenum chamber cover - B -.
- Install the remaining removed parts in the opposite order.
- Energize the voltage to the high voltage system.
Restart the high voltage system
Risk of electrocution
Death or serious bodily injury by electric shock
• People with electric/medical life- and health sustaining devices in or on their person must not perform any work on the high voltage system for safety reasons. Internal pain killer pumps, implanted defibrillators, pacemakers, insulin pumps and hearing aids among others are considered life- and health sustaining devices.
• The high voltage system may only be restarted by qualified personal (Audi high voltage technicians).
• Assure that the restart is performed exclusively using the Vehicle Diagnosis Tester according to the "Guided Fault Finding".
• The qualified personal (Audi high voltage technician) restarts the vehicle.
• The qualified personal (Audi high voltage technicians) marks the vehicle by attaching warning labels.
• Restart the high voltage system:
• Connect the vehicle diagnosis tester
• Select the Guided Fault Finding mode
• Using the GO TO button, select the following menu commands
• Functions/Component selection
• Body
• Electrical Equipment
• OBD-capable system
• 8C - Hybrid battery management -J840
• 8C - Hybrid battery management, functions
• 51 - High voltage restart (Rep.Gr. 93)
For vehicles without a high voltage system
- Reconnect the battery (A) ground connection; when doing this, pay attention to the notes regarding reconnecting the battery.
- Install the remaining removed parts in the opposite order.
All vehicles
- Evacuate and fill the refrigerant circuit.
- Switch on the ignition.
- Perform a basic setting and the output Diagnostic Test Mode (DTM) on the A/C system using the Vehicle diagnostic tester in "Guided Fault Finding".
• On this vehicle, the control motors are equipped with electronics. During the first basic setting, a new control motor learns its position on the air conditioner and can then be controlled by the Climatronic Control Module (J255) (currently all control motors are identical). Refer to the Vehicle diagnostic tester in "Guided Fault Finding".
• During the basic setting, the control motors are assigned and adapted corresponding to the switching sequence of the wiring. If this sequence does not conform the specification, the control motors will adapt incorrectly and the door control will be wrong. Refer to => [ A/C Control Motor Block Diagram ] A/C Control Motor Block Diagram.
- Check the Climatronic Control Module DTC memory and erase any faults using the Vehicle diagnostic tester in "Guided Fault Finding".
- Operate the A/C system after filling the refrigerant circuit. Refer to => [ A/C System, Operating after Filling Refrigerant Circuit ] A/C System, Operating After Filling Refrigerant Circuit.