Air Conditioning Audi A4 B6

Safety precautions

The following safety precautions have to be observed for these cooling aids (additional laws may apply for different countries).

Safety precautions for handling of refrigerant

The subassemblies and lines of the air conditioner are filled with the following refrigerant

1,1,1,2 Tetrafluoroethane (CF 3 -CH 2 F or CH 2 F-CF 3 )

This refrigerant is commonly known as R-134a, H-FKW 134a, SUVA 134a and KLEA 134a (in the USA different names may apply as well).

Refrigerant R-134A replaces the refrigerant R-12 which is reported to have harmful effects on the ozone layer of the earth's atmosphere.

R-134a and R-12 systems are similar in design but there are very important differences in the refrigerants, lubricating oils, service equipment and A/C system components.

If it is necessary to open the refrigerant circuit during service work, discharge the refrigerant circuit first (see A/C REFRIGERANT SYSTEM (R-134A), DISCHARGING ). Avoid contact with liquid refrigerant or refrigerant gases. If refrigerant should escape although all safety caution were observed, do not inhale refrigerant/air mixture.

Always wear hand and eye protection (gloves and goggles) when working around the A/C refrigerant system and switch on existing exhaust/ventilation systems.

Reason

Unprotected body parts may freeze under intensive impact of refrigerant aid.

Technicians must be trained!

1. As of January 1, 1992 any person who services a motor vehicle air conditioner MUST, by law, be properly trained and certified and use approved refrigerant recycling equipment. Technicians must complete an EPA approved recycling course to be certified.
2. State and Provincial governments may have additional requirements regarding air conditioning servicing. Always comply with state and local laws.

Although refrigerant is not flammable, smoking, welding or soft or hard soldering is not permitted in a room aerated with refrigerant.

The refrigerant gas is chemically split via the high temperature of the open flame or via the hot body. Breathing poisoning refrigerant vapors leads to irritated eyes, nose and throat.

Discharge refrigerant circuit

The refrigerant must be discharged using an air conditioning service station and should not be released into the environment. The discharged refrigerant will be locally recycled or sent to an recycling facility or to the manufacturer (different or additional laws may apply in USA). To discharge refrigerant (see A/C REFRIGERANT SYSTEM (R-134A), DISCHARGING ).

If refrigerant R-134a is released into the environment, it may enhance the green house effect.

Note. Compared to R-12, R-134a has a substantially lower green house effect. Because R-134a does not contain chlorine atoms, the major catalyst in ozone depletion, R-134-a has no ozone depletion potential. The ozone depletion in the upper atmosphere is only initiated by splitting carbon-chlorine bonds (e.g. properties of R-12)

After discharging the air conditioner, disconnect harness connector from A/C Compressor Regulator Valve -N280- or High Pressure Sensor -G65-.

The A/C Compressor Regulator Valve -N280- is not activated and the compressor runs at idle. This compressor is constructed in such a way, that the components are lubricated at idle via an internal oil circuit (as long as enough oil is in compressor).

Work on refrigerant circuit

Work on refrigerant system should only be carried out in a well ventilated area (workshops). Make sure that with in 5 meters circumference are no working-pits, basement staircases or shafts. Switch on existing/ventilation systems when working on the refrigerant system.

Refrigerant is colorless, odorless and heavier than air and therefore displaces oxygen. Should refrigerant escape although all safety precautions were observed, a danger of suffocation exists in non vented rooms and work pits.

Note. The escaping refrigerant/air mixture should not be inhaled, but should be sucked out via an existing exhaust ventilation system.

Do not attempt repair on a pressurized air conditioning systems by soldering, brazing or welding. This also applies to welding and soldering work on the vehicle, which may cause components of the climate control system may heat up.

A high positive pressure occurs in the system when heating, this can lead to an explosion.

Corrective action

Discharge A/C refrigerant system (see A/C REFRIGERANT SYSTEM (R-134A), DISCHARGING .)

Note. Always replace damaged and/or leaking A/C system components. Do not attempt repair by soldering, brazing or welding.

Immediately plug open connections on A/C system when servicing the system.

Moisture enters the A/C system and components when system is opened for longer periods of time. An A/C system that has been open for a longer period of time cannot be filled again without replacing components of the system.

Paint work on vehicles with A/C systems

Surface temperatures of 80 °C should not be exceeded in the drying-oven or the pre-warm zone during the paint job.

A high positive pressure occurs in the system when heating, this can lead to an explosion.

PAG oil absorbs moisture!

1. R-134a refrigerant system oil (PAG oil) absorbs moisture very rapidly. Moisture combines with the refrigerant to form acids which will damage the system. Use only the specified oil from a sealed container and ALWAYS reseal the oil container immediately after use. DO NOT use oil if it has become contaminated with moisture or if container has been left open.
2. Immediately plug open connections on A/C components to prevent dirt and moisture contamination. Likewise, DO NOT remove new component from packaging until ready to install. Immediately tighten component connections after installation.

Use only approved equipment!

1. Discharge A/C system using refrigerant recovery/recycling/recharging unit Kent-Moore ACR 4 , or equivalent, before removing any A/C system component.
2. After emptying A/C refrigerant, disconnect power supply from A/C pressure switch -F129- and high pressure sensor -G65- to prevent accidental compressor operation with A/C system discharged.
3. Always replace O-rings, DO NOT reuse. Use only the correct size and type of O-rings specified for use with R-134a refrigerant. Lubricate O-ring with R-134a refrigerant oil before installing.
4. Always reinstall sealing cap(s) over A/C service valve(s)

A/C system, general repair guidelines

The A/C system must not be discharged and opened (see WORK ON REFRIGERANT CIRCUIT ) unless this is necessary due to safety precautions or unless components of the refrigerant circuit of the A/C system have to be to replaced (see DISCHARGE REFRIGERANT CIRCUIT .)

When performing all other usual vehicle repair work, the refrigerant circuit of the A/C system should also remain closed.

Servicing operations that can be carried out on the heating and air conditioning system without opening the refrigerant circuit, are described in this Repair Manual. See A/C SYSTEM CONTROL AND REGULATION COMPONENTS

Note. The connections for sensors/switches mentioned in this Repair Manual are provided with a valve that closes automatically when the switches/sensors are unscrewed. These switches can be replaced without discharging the refrigerant circuit.

Description for servicing operations to A/C systems that require discharging the refrigerant circuit, see A/C REFRIGERANT SYSTEM (R-134A), DISCHARGING .

Note. For the Audi Cabriolet, different settings for closed and open convertible top are stored in the A/C Control Head -E87-. When opening and closing the convertible top, the A/C Control Head -E87- independently changes the setting to the value which was last adjusted during closed or open convertible top. As of model year 2002, A/C Control Head -E87- with part number as of index "H" (with hard-/software version as of "XX15") will be implemented as a running change. The temperature regulation for the passenger compartment is laid out somewhat lower. for the A/C Control Heads -E87-. See Parts catalog For vehicles as of model year 2003, only A/C Control Heads -E87- with part number as of index "H" must have been or must be installed. For vehicles with 4 cyl. engine with direct fuel injection (FSI), only A/C Control Heads -E87- with part number as of index "H" must have been or must be installed. See Parts catalog As of model year 2003, A/C Control Head -E87- with part number as of index "H" (with hard-/software version as of "XX16") will be implemented as a running change. These A/C Control Heads -E87- differ from the software version as of "XX15" in the following points

1. The temperature regulation for the passenger compartment on the Audi Cabriolet and open convertible top was laid out somewhat lower.
2. The temperature adjustment range was expanded, the lowest temperature of 16°C can now be selected (instead of previous 18 °C). See Parts catalog

Refrigerant system, servicing

Note. For service work on refrigerant circuit, see A/C REFRIGERANT SYSTEM, SERVICING . All work or components marked with a 1) can be serviced or replaced without discharging the refrigerant circuit (work that does not pertain to refrigerant circuit). All components as well as refrigerant hoses and lines that are not marked with a 1) , can be replaced only with the refrigerant circuit discharged. For vehicles with 8 cyl. engine, the compressor is driven by a shaft, rather than a belt. See VEHICLES WITH 8 CYL. ENGINE (COMPRESSOR DRIVE VIA A SHAFT) .

Component overview

HD = High pressure side

ND = Low pressure side

The following list pertains to (Scheme 1).

1. A/C Compressor Regulator Valve -N280- 1) Checking activation and function, see «ACTIVATION FOR A/C COMPRESSOR REGULATOR VALVE -N280»(/audi/a4/b6-2000-2006/remont/communication-devices/#on-board-diagnostic-obd) )
2. Compressor 1) Compressor from bracket, removing and installing, see «COMPRESSOR, REMOVING AND INSTALLING FROM BRACKET»(/audi/a4/b6-2000-2006/remont/automatic-hvac-system/#air-conditioning) ) When installing refrigerant lines/hoses and bracket, make sure there is a sufficient gap between belt, bracket and belt pulley The compressor construction differs depending on the engine Different compressor types are installed depending on country variants (e.g. Denso, model designation 7SEU series USA)
3. Belt pulley drive unit - compressor to engine Replacing belt pulley, see «BELT PULLEY/DRIVE UNIT OF COMPRESSOR, REPLACING»(/audi/a4/b6-2000-2006/remont/automatic-hvac-system/#air-conditioning) Ribbed belt, removing and installing: See «RIBBED BELT, REMOVING AND INSTALLING»(ref-197056-S06598932702005101100000) for the 1.8L engine, or «RIBBED BELT, REMOVING AND INSTALLING»(ref-197058-S42630607092005101100000) for the 3.0L engine. Drive unit-compressor, checking, replacing, see «COMPRESSOR DRIVE UNIT, CHECKING, REPLACING»(/audi/a4/b6-2000-2006/remont/automatic-hvac-system/#air-conditioning__compressor-drive-unit-checking-replacing) NOTE: A rubber element is installed between the belt pulley drive unit and compressor drive shaft to protect the drive gear in the event that the compressor is seized or does not move freely. The rubber element disables the power transfer to the compressor, if the compressor produces friction. A rubber element is installed between the engine and compressor to protect the drive gear if the compressor is seized or does not move freely. Vibrations which may occur during compressor operation can be eliminated via the rubber element (dampening function during torque tightening).
4. Oil drain plug
5. High pressure relief valve
6. Circuit with valve
7. High Pressure Sensor of A/C system -G65- 1) Removing and installing, see «HIGH PRESSURE SENSOR -G65-, REMOVING AND INSTALLING»(/audi/a4/b6-2000-2006/remont/automatic-hvac-system/#air-conditioning__high-pressure-sensor-g65-removing-and) Checking signal, see «TEST STEPS 5 TO 9»(/audi/a4/b6-2000-2006/remont/communication-devices/#on-board-diagnostic-obd)
8. Condenser
9. Closing cap With seal Always install
10. Service connection High pressure side For measuring, discharging and charging

High Pressure Sensor -G65-, removing and installing

The pressure sensor produces a triangular signal when current is applied. This signal changes according to the pressure in the system. The signal is used by the connected control modules (coolant fan control module, engine control module) to control the pressure in the refrigerant circuit and accordingly controls the cooling fan and the engine.

1. Remove front bumper: For Cabriolet models, see «FRONT BUMPER»(/audi/a4/b6-2000-2006/remont/exterior-body-panels/#bumpers-cabriolet) . For models other than Cabriolet, see «FRONT BUMPER»(/audi/a4/b6-2000-2006/remont/exterior-body-panels/#bumpers-except-cabriolet) .
2. Disconnect connector -B-.
3. Remove High Pressure Sensor -G65- Tightening torque: 5 Nm.
4. O-Ring-seal -A- (10.8 mm x 1.8 mm) replace, see «O-RING SEALS FOR REFRIGERANT CIRCUIT»(/audi/a4/b6-2000-2006/remont/automatic-hvac-system/#air-conditioning__o-ring-seals-for-refrigerant-circuit) .

Note. The cooling performance cannot be checked with High Pressure Sensor -G65-, the A/C Control Head -E87- does not switch on the compressor. The refrigerant circuit remains closed, connection with valve. Checking function and delivered signal of High Pressure Sensor -G65-, see TEST STEPS 5 TO 9 and PRESSURE SIGNAL FROM HIGH PRESSURE SENSOR -G65 .

O-ring seals for refrigerant circuit

1. Always replace.
2. Lubricate with refrigerant oil before installing.
3. Ensure seal fits properly on line or notch.
4. Work in clean environment.

Note. Use only O-rings that are resistant to refrigerant R-134a and refrigerant oil. These O-rings are color-coded to avoid mistakes (currently red, light purple and dark purple). In addition to the color-coded O-rings, black O-rings are also used in production for certain connections. The O-ring dimension -a- and -b- are different depending on installation location: In January 2003, the connections of the refrigerant lines to the different components (condenser, evaporator, etc.) have been changed from radial-/axial seals to radial seals. Only components of the same type of seal and the O-ring seals provided for them (different versions) may be installed with each other. If components with a different seal are installed, a secure seal cannot be established at the connection points.

Vehicles with 4 or 6 cyl. engine (compressor drive via a belt)

Note. The compressor can be removed and installed from the bracket without opening the refrigerant lines. Do not discharge the refrigerant circuit, and do not loosen or remove refrigerant lines from compressor. After removal fasten compressor to long member (e.g. using a wire). Do not let compressor hang from refrigerant lines. Mark direction of rotation of ribbed belt using chalk or felt tip marker. Reversing the direction of rotation of a used belt can destroy the belt. Different compressors are installed depending on engine and country variant (installed at right or left of engine, 4, 6 or 8 cyl. engine etc.).

Note. The illustration shows the compressor on a 4-cylinder gas Turbo engine. On different engine variants the arrangement deviates only slightly from this illustration (e.g. different refrigerant lines). Remove noise insulation: See NOISE INSULATION, ASSEMBLY OVERVIEW (except Cabriolet), or NOISE INSULATION, ASSEMBLY OVERVIEW for the Cabriolet. Move the lock carrier into service position: See LOCK CARRIER, MOVING TO SERVICE POSITION (except Cabriolet), or LOCK CARRIER, MOVING TO SERVICE POSITION for the Cabriolet. Remove oil filter. Protect sealing surface from damage (only on vehicles with 6-cylinder gas engine): See ENGINE OIL, DRAINING OR EXTRACTING, CHANGE OIL FILTER . Remove bolts -A- (25 Nm). Bring lock carrier into service position (only if the ribbed belt and the compressor cannot be removed without being in service position, for example, on the 6 cyl. engine): See LOCK CARRIER, MOVING TO SERVICE POSITION (except Cabriolet). For Cabriolet, see LOCK CARRIER, MOVING TO SERVICE POSITION .

Note. Install one washer -B- on each bolt -A-. Before fastening the compressor, make sure both bushings -C- in bracket or compressor are seated correctly. After mounting the compressor, make sure refrigerant lines -A-, are engaged in bracket -B-. After mounting the compressor, make sure the refrigerant lines and brackets have sufficient gap between other components. On vehicles with 6 cylinder engines make sure there is enough space between belt, bracket and belt pulley.

Vehicles with 8 cyl. engine (compressor drive via a shaft)

Note. The compressor is driven via a gear and a drive shaft -B-. Removing and installing compressor bracket from engine. See appropriate mechanical file in Engine . For vehicles with 8 cyl. engine, the refrigerant circuit must be evacuated and then both refrigerant lines must be removed from compressor to be able to remove the compressor. See REFRIGERANT LINES ON COMPRESSOR, REMOVING AND INSTALLING . Remove compressor from bracket and install again. See COMPRESSOR, REMOVING AND INSTALLING (FOR VEHICLES WITH A 4 OR 6 CYL. ENGINE) .

Belt pulley (version 1), replacing

Note. Different versions of the pulley are installed, depending on compressor type and engine version Pulley, removing from compressor and reinstalling, see PULLEY, REMOVING FROM COMPRESSOR AND RE-INSTALLING (VERSION 1)

The following list pertains to (Scheme 7).

1. Bolt Replace Tightening torque 20 Nm. loosening and tightening, see «PULLEY, REMOVING FROM COMPRESSOR AND RE-INSTALLING (VERSION 1)»(/audi/a4/b6-2000-2006/remont/automatic-hvac-system/#air-conditioning__pulley-removing-from-compressor-and-re-installing)
2. Drive plate Different versions Removing and installing, see «PULLEY, REMOVING FROM COMPRESSOR AND RE-INSTALLING (VERSION 1)»(/audi/a4/b6-2000-2006/remont/automatic-hvac-system/#air-conditioning__pulley-removing-from-compressor-and-re-installing) Disengages with torque too high (e.g. compressor produces friction)
3. Securing ring Replace Install on proper side (side level to compressor) Removing and installing, see «PULLEY, REMOVING FROM COMPRESSOR AND RE-INSTALLING (VERSION 1)»(/audi/a4/b6-2000-2006/remont/automatic-hvac-system/#air-conditioning__pulley-removing-from-compressor-and-re-installing)
4. Belt pulley Rubber element of pulley disengages when torque is too-high (e.g. compressor produces friction) and pulley runs freely without driving the compressor. Different versions Removing and installing, see «PULLEY, REMOVING FROM COMPRESSOR AND RE-INSTALLING (VERSION 1)»(/audi/a4/b6-2000-2006/remont/automatic-hvac-system/#air-conditioning__pulley-removing-from-compressor-and-re-installing) NOTE: Under certain conditions (e.g. rough engine idle), rubber element of pulley can disengage without a malfunction existing at compressor or in refrigerant circuit.
5. Compressor Different versions are installed, depending on engine version and country version of vehicle. Clean compressor flange before sliding on pulley.

Pulley, removing from compressor and re-installing (version 1)

Note. If overload protection of pulley triggers, check compressor for ease of motion before replacing the pulley. If compressor creates friction, replace it completely. To remove pulley, it depends on engine version if it is necessary to remove compressor from engine. See COMPRESSOR, REMOVING AND INSTALLING (FOR VEHICLES WITH A 4 OR 6 CYL. ENGINE) . The compressor can be removed and installed from the bracket without opening the refrigerant lines. See COMPRESSOR, REMOVING AND INSTALLING (FOR VEHICLES WITH A 4 OR 6 CYL. ENGINE) . Mark direction of rotation of ribbed belt using chalk or felt tip marker before removing. Reversing the direction of rotation of a run-in belt can destroy the belt. Different compressors are installed, depending on engine and country version (installed on right or left at engine, 6-cyl. gasoline or diesel engine, cold or hot country).

Scheme 1

Scheme 2

1. Remove noise insulation: See «NOISE INSULATION, ASSEMBLY OVERVIEW»(/audi/a4/b6-2000-2006/remont/exterior-body-panels/#body-front-except-cabriolet__noise-insulation-assembly-overview) (except Cabriolet). For the Cabriolet, see «NOISE INSULATION, ASSEMBLY OVERVIEW»(/audi/a4/b6-2000-2006/remont/exterior-body-panels/#body-front-cabriolet__noise-insulation-assembly-overview) .
2. Bring the lock carrier into service position: See «LOCK CARRIER, MOVING TO SERVICE POSITION»(/audi/a4/b6-2000-2006/remont/exterior-body-panels/#body-front-except-cabriolet__lock-carrier-moving-to-service-position) (except Cabriolet). For the Cabriolet, see «LOCK CARRIER, MOVING TO SERVICE POSITION»(/audi/a4/b6-2000-2006/remont/exterior-body-panels/#body-front-cabriolet__lock-carrier-moving-to-service-position) .
3. Release tension on ribbed belt and remove it. See «RIBBED BELT, REMOVING AND INSTALLING»(ref-197056-S06598932702005101100000) for the 1.8L engine, or «RIBBED BELT, REMOVING AND INSTALLING»(ref-197058-S42630607092005101100000) for the 3.0L engine.
4. Remove bolt -A- (tightening torque 20 Nm). NOTE: If pulley cannot be removed with compressor installed, remove compressor from engine. See «COMPRESSOR, REMOVING AND INSTALLING (FOR VEHICLES WITH A 4 OR 6 CYL. ENGINE)»(/audi/a4/b6-2000-2006/remont/automatic-hvac-system/#air-conditioning) . To loosen and tighten bolt -A-, counter-hold it at drive plate -B- using a commercially available pin wrench -C- (pin diameter 5.0 mm). Bolt -A- must be replaced (because of locking compound).
5. Carefully pry off drive plate -A- using 2 screwdrivers -B-. NOTE: Make sure that the collar for pulley -C- is not damaged when prying off drive plate -A-. There are different versions of pulley -C- and drive plate -A-, therefore note the exact dimensions.
6. Remove securing ring -A-.
7. Remove pulley -B-.

Installing

1. Installation is reverse of removal.

Note. Replace securing ring -A-. When installing securing ring -A-, make sure it is not bent up more than is necessary for installation. Insert securing ring -A- on proper side, the side with installing slopes -C- faces away from compressor (install flat side facing compressor). Ensure proper seating of securing ring in groove on compressor flange. Clean compressor flange before installing the pulley, as pulley must be able to be installed easily. (Installing must be possible without excessive force).

Belt pulley (version 2), replacing

Note. Different versions of the pulley are installed, depending on compressor type and engine version See Parts Catalog Pulley, removing from compressor and re-installing, see PULLEY, REMOVING FROM COMPRESSOR AND RE-INSTALLING (VERSION "2")

The following list pertains to (Scheme 12).

1. Securing ring Carefully remove using a small screwdriver or needle-nose pliers (while doing so, pay special attention to belt pulley) Removing and installing, see «PULLEY, REMOVING FROM COMPRESSOR AND RE-INSTALLING (VERSION "2")»(/audi/a4/b6-2000-2006/remont/automatic-hvac-system/#air-conditioning__pulley-removing-from-compressor-and-re-installing)
2. Drive plate Bolted to drive shaft of compressor Different versions See Parts Catalog With overload protection, triggers when torque is too-high (e.g. compressor produces friction) and belt pulley runs freely without driving the compressor. Removing and installing, see «PULLEY, REMOVING FROM COMPRESSOR AND RE-INSTALLING (VERSION "2")»(/audi/a4/b6-2000-2006/remont/automatic-hvac-system/#air-conditioning__pulley-removing-from-compressor-and-re-installing) Tightening torque 35 Nm
3. Securing ring Replace Install on proper side (level side to compressor) Removing and installing, see «PULLEY, REMOVING FROM COMPRESSOR AND RE-INSTALLING (VERSION "2")»(/audi/a4/b6-2000-2006/remont/automatic-hvac-system/#air-conditioning__pulley-removing-from-compressor-and-re-installing)
4. Spacing disc Dimensions: 17.5 x 10 x 3 mm
5. Rubber element 6x, install on correct side, see «PULLEY, REMOVING FROM COMPRESSOR AND RE-INSTALLING (VERSION "2")»(/audi/a4/b6-2000-2006/remont/automatic-hvac-system/#air-conditioning__pulley-removing-from-compressor-and-re-installing) Decouple belt pulley from compressor input shaft, damps vibrations and noise. When installing, coat rubber element lightly e.g. using tire mounting paste or a soap solution (as sliding compound).
6. Belt pulley Belt pulley is made of plastic and is impact sensitive, therefore handle it especially carefully. Different versions See Parts Catalog Removing and installing, see «PULLEY, REMOVING FROM COMPRESSOR AND RE-INSTALLING (VERSION "2")»(/audi/a4/b6-2000-2006/remont/automatic-hvac-system/#air-conditioning__pulley-removing-from-compressor-and-re-installing)
7. Compressor Different versions are installed, depending on engine version and country version of vehicle. See Parts Catalog Clean compressor flange before sliding on pulley.

Pulley, removing from compressor and re-installing (version "2")

Note. Observe the notes for removing belt pulley version "1", these also apply for version "2. See PULLEY, REMOVING FROM COMPRESSOR AND RE-INSTALLING (VERSION 1) . Perform the preparation work as described for removing belt pulley version "1". See PULLEY, REMOVING FROM COMPRESSOR AND RE-INSTALLING (VERSION 1) . Belt pulley is made of plastic and is impact-sensitive, therefore handle it especially carefully. If overload protection of drive plate -C- is triggered, drive plate can be pried off from belt pulley -D- after removing securing ring -A-.

Removing and installing belt pulley version "2"

Removing

1. Remove securing ring -A- e.g. carefully remove using a small screwdriver or needle-nose pliers (while doing this, pay special attention to belt pulley, do not damage it).
2. Hold compressor input shaft -B- in position e.g. using socket wrench T10001/10 from socket wrench set and turn drive plate -C- with belt pulley -D- in direction of arrow -E- (tightening torque 35 Nm).
3. Remove securing ring -A-.
4. Remove pulley -B-.

Installing

Note. Replace securing ring -A-. Clean compressor flange before sliding on belt pulley. When installing securing ring -A-, note that it cannot be bent open more than is necessary for installation.

1. Install pulley -B-.
2. Insert securing ring -A- on proper side, the side with beveled insertion edge -C- faces away from compressor (install flat side facing compressor).
3. Insert rubber elements -D- in belt pulley -B- according to illustration.
4. When installing drive plate, coat rubber elements -D- lightly; for example, using tire mounting paste or soap solution (as sliding compound).
5. Insert drive plate -C- as far into rubber elements -D- (see graphic A87-0633) until it contacts compressor shaft -B-.
6. Thread drive plate -C- on to compressor shaft -B- by turning in direction of arrow -F-.
7. Tighten drive plate -C- (over the belt pulley -D-) in direction of arrow -F- to 35 Nm using a standard band wrench (with webbed band), counter hold compressor shaft -A- on compressor shaft -B- using a counterholder tool -B- (e.g. socket wrench from T10001/10 socket wrench set).
8. Install securing ring -A-.

Compressor drive unit, checking, replacing

Note. If overload protection of drive plate has triggered, check compressor for ease of motion before replacing the drive unit. If compressor creates friction, replace it completely.

The following list pertains to (Scheme 18).

1. Compressor drive shaft Check. The drive shaft must be seated free of play in splines of engine drive wheel with thread tightened. See «COMPRESSOR DRIVE SHAFT, REMOVING AND INSTALLING»(/audi/a4/b6-2000-2006/remont/automatic-hvac-system/#air-conditioning) . Tightening torque 60 Nm Loosening and tightening, see «COMPRESSOR DRIVE SHAFT, LOOSENING AND TIGHTENING»(/audi/a4/b6-2000-2006/remont/automatic-hvac-system/#air-conditioning__compressor-drive-shaft-loosening-and-tightening) Removing and installing, see «COMPRESSOR DRIVE SHAFT, REMOVING AND INSTALLING»(/audi/a4/b6-2000-2006/remont/automatic-hvac-system/#air-conditioning) . Lubricate splines of engine drive wheel using G 000 100 clutch splining grease. See Parts Catalog
2. Socket head bolt Tightening torque 8 Nm
3. Drive plate With overload protection, triggers when torque is too-high (e.g. compressor produces friction) and drive shaft runs freely without driving the compressor. Run-out, checking and adjusting, see «RUN-OUT OF DRIVE PLATE WITH OVERLOAD PROTECTION, CHECKING AND ADJUSTING»(/audi/a4/b6-2000-2006/remont/automatic-hvac-system/#air-conditioning__run-out-of-drive-plate-with-overload) . Removing and installing, see «DRIVE PLATE WITH OVERLOAD PROTECTION, REMOVING AND INSTALLING»(/audi/a4/b6-2000-2006/remont/automatic-hvac-system/#air-conditioning__drive-plate-with-overload-protection-removing)
4. Drive plate Threaded to drive shaft of compressor With overload protection, triggers when torque is too-high (e.g. compressor produces friction) and drive shaft runs freely without driving the compressor. Tightening torque 35 Nm Removing and installing, see «DRIVE PLATE TO COMPRESSOR, REMOVING AND INSTALLING»(/audi/a4/b6-2000-2006/remont/automatic-hvac-system/#air-conditioning__drive-plate-to-compressor-removing-and)
5. Rubber element Disengages drive unit, damps vibrations and noise. When installing, coat rubber element lightly e.g. using tire mounting paste or a soap solution (as sliding compound). Removing and installing, see «DRIVE PLATE TO COMPRESSOR, REMOVING AND INSTALLING»(/audi/a4/b6-2000-2006/remont/automatic-hvac-system/#air-conditioning__drive-plate-to-compressor-removing-and)
6. Spacing disc Dimensions: 17.5 x 10 x 3 mm
7. Snap ring Replace Install on proper side (level side to compressor) Removing and installing, see «DRIVE PLATE WITH ROLLER BEARING, REMOVING AND INSTALLING»(/audi/a4/b6-2000-2006/remont/automatic-hvac-system/#air-conditioning__drive-plate-with-roller-bearing-removing)
8. Drive plate With roller bearing. Removing and installing, see «DRIVE PLATE WITH ROLLER BEARING, REMOVING AND INSTALLING»(/audi/a4/b6-2000-2006/remont/automatic-hvac-system/#air-conditioning__drive-plate-with-roller-bearing-removing) Clean compressor flange before sliding on drive plate.
9. Compressor Different versions may be installed, depending on engine version and country version of vehicle. See Parts Catalog

Compressor drive shaft, loosening and tightening

Note. Extensive preparations are necessary in order to be able to loosen the compressor drive shaft. See REMOVING (COMPRESSOR DRIVEN VIA A BELT) . Drive shaft can also be checked and tightened without opening the refrigerant circuit.

Drive shaft, loosening

1. Remove the components which prevent access to drive shaft. See «REMOVING (COMPRESSOR DRIVEN VIA A BELT)»(/audi/a4/b6-2000-2006/remont/automatic-hvac-system/#air-conditioning) .
2. Hold compressor drive shaft -A- in place using open-end wrench and turn compressor drive unit -B- in direction of arrow -C-.

Note. Drive shaft -A- must not be turned. Drive shaft -A- can be slid into drive wheel through the boot -E- after loosening threaded connection. After installing drive shaft -A-, check installation position of boot -E-.

Drive shaft, tightening

1. Hold compressor drive shaft -A- in place using an open-end wrench and turn compressor drive unit -B- in direction of arrow -D- (tightening torque 60 Nm).
2. After tightening compressor drive shaft, check installation position of boot -E

Removing

1. Remove compressor. See «COMPRESSOR, REMOVING AND INSTALLING (VEHICLES WITH 8 CYL. ENGINE)»(/audi/a4/b6-2000-2006/remont/automatic-hvac-system/#air-conditioning) .
2. Remove boot -A
3. Remove drive shaft -B- from splines of drive pinion -C

Installation is the reverse of removal, noting the following

1. Check drive shaft -B-, splines must show no traces of wear and must be seated free of play in splines of drive wheel -C
2. Coat splines of drive shaft -B- using clutch splining grease G 000 100 before installing.
3. Insert drive shaft -B- before installing compressor and slide it into drive wheel -C- up to stop.
4. After installing compressor, check installation position of boot -A-.

Drive plate with overload protection, removing and installing

1. Remove compressor, see «COMPRESSOR, REMOVING AND INSTALLING (FOR VEHICLES WITH A 4 OR 6 CYL. ENGINE)»(/audi/a4/b6-2000-2006/remont/automatic-hvac-system/#air-conditioning)

1. Remove bolts -A

Note. Use a commercially available band wrench (with webbed band) to counterhold at drive plate -C-.

Scheme 3

1. Position drive plate with overload protection -B- onto drive plate -C-.
2. Insert bolts -A- and tighten by hand.
3. Check run-out of drive plate -B-, see «RUN-OUT OF DRIVE PLATE WITH OVERLOAD PROTECTION, CHECKING AND ADJUSTING»(/audi/a4/b6-2000-2006/remont/automatic-hvac-system/#air-conditioning__run-out-of-drive-plate-with-overload) .
4. Tighten bolts -A- (tightening torque 8 Nm).
5. Check run-out of drive plate -B- once more, see «RUN-OUT OF DRIVE PLATE WITH OVERLOAD PROTECTION, CHECKING AND ADJUSTING»(/audi/a4/b6-2000-2006/remont/automatic-hvac-system/#air-conditioning__run-out-of-drive-plate-with-overload) .

Run-out of drive plate with overload protection, checking and adjusting

1. Remove compressor. See «COMPRESSOR, REMOVING AND INSTALLING (FOR VEHICLES WITH A 4 OR 6 CYL. ENGINE)»(/audi/a4/b6-2000-2006/remont/automatic-hvac-system/#air-conditioning) .
2. Clean flange at drive plate -A
3. Secure a dial gauge -B- to compressor using a dial gauge holder -C- (e.g. 387 special tool holder).
4. Set dial gauge indenter of dial indicator -D- on flange of drive plate -A- with a pre-tension of approx. 1.0 mm.
5. Turn compressor drive unit -E- several rotations. Specification: Run-out deviation is less than 0.21 mm (run-out of dial indicator, difference between smallest and largest measured value 0.2 mm maximum).
6. If run-out deviation is greater than 0.2 mm, loosen bolts on drive plate. See «DRIVE PLATE WITH OVERLOAD PROTECTION, REMOVING AND INSTALLING»(/audi/a4/b6-2000-2006/remont/automatic-hvac-system/#air-conditioning__drive-plate-with-overload-protection-removing) and re-adjust drive plate.

Drive plate to compressor, removing and installing

1. Remove drive plate with overload protection. See «DRIVE PLATE WITH OVERLOAD PROTECTION, REMOVING AND INSTALLING»(/audi/a4/b6-2000-2006/remont/automatic-hvac-system/#air-conditioning__drive-plate-with-overload-protection-removing) .

1. Loosen drive plate -C- by turning in direction of arrow -D- using a commercially available band wrench (with band strap), counter hold compressor shaft -A- using a counter holder tool -B- (e.g. socket wrench from T10001/10 socket wrench set or 3079 counter holder) on compressor shaft -A

1. When installing, coat rubber element -B- lightly e.g. using tire mounting paste or soap solution (as sliding compound).
2. Insert rubber element -B- in drive plate -A- according to illustration.
3. Insert drive plate -A- with rubber elements -B- onto drive plate -C- according to illustration until it makes contact with compressor shaft.
4. Thread drive plate -C- onto compressor shaft -A- by turning in direction of arrow -E-.
5. Tighten drive plate -C- by turning in direction of arrow -E- to 35 Nm using a standard band wrench (with band strap), counter hold compressor shaft -A- using a counter-holder tool -B- (e.g. socket wrench from T10001/10 socket wrench set) on compressor shaft -A-.

Drive plate with roller bearing, removing and installing

1. Remove drive plate from compressor shaft. See «DRIVE PLATE TO COMPRESSOR, REMOVING AND INSTALLING»(/audi/a4/b6-2000-2006/remont/automatic-hvac-system/#air-conditioning__drive-plate-to-compressor-removing-and) .
2. Remove securing ring -A-.
3. Remove drive plate -B-.

Scheme 4

Note. Replace securing ring -A-. Clean compressor flange before sliding on drive plate. When installing securing ring -A-, note that it cannot be bent open more than is necessary for installation. Insert securing ring -A- on proper side, the side with beveled insertion edge -C- faces away from compressor (install with flat side facing compressor).

Notes

1. Service work on refrigerant circuit, see «A/C REFRIGERANT SYSTEM, SERVICING»(/audi/a4/b6-2000-2006/remont/automatic-hvac-system/#air-conditioning__ac-refrigerant-system-servicing)
2. After completion of repair carry out the following Check DTC memory. See «DIAGNOSTIC TROUBLE CODE (DTC) MEMORY, CHECKING (FUNCTION 02)»(/audi/a4/b6-2000-2006/remont/communication-devices/#on-board-diagnostic-obd__diagnostic-trouble-code-dtc-memory-checking) Initiate basic setting. See «BASIC SETTING (FUNCTION 04)»(/audi/a4/b6-2000-2006/remont/communication-devices/#on-board-diagnostic-obd__basic-setting-function-04) . Erase DTC memory. See «DIAGNOSTIC TROUBLE CODE (DTC) MEMORY, ERASING (FUNCTION 05)»(/audi/a4/b6-2000-2006/remont/communication-devices/#on-board-diagnostic-obd__diagnostic-trouble-code-dtc-memory-erasing) .
3. For electrical testing on components marked with a "1)", «AUTOMATIC CLIMATE CONTROL SYSTEM, ELECTRICAL TESTING»(/audi/a4/b6-2000-2006/remont/communication-devices/#on-board-diagnostic-obd) .
4. All components marked with a "2)" will be activated during the output Diagnostic Test Mode (DTM). See «OUTPUT DIAGNOSTIC TEST MODE (DTM) (FUNCTION 03)»(/audi/a4/b6-2000-2006/remont/communication-devices/#on-board-diagnostic-obd__output-diagnostic-test-mode-dtm-function) .
5. The center defroster vent for the front windshield can be replaced without removing the instrument panel. See «INSTRUMENT PANEL»(/audi/a4/b6-2000-2006/remont/gauges-instrument-panels/#interior-trim-except-cabriolet) (except Cabriolet). See «INSTRUMENT PANEL»(/audi/a4/b6-2000-2006/remont/gauges-instrument-panels/#interior-trim-cabriolet) for the Cabriolet.

Components in engine compartment and rear of vehicle

The following list pertains to see scheme 29.

1. Sunroof with solar cells Not applicable in USA
2. Service connection Low pressure side For measuring, discharging and charging Cap with seal, always re-install after using service valve
3. Dust and pollen filter Removing and installing, see «DUST AND POLLEN FILTER ELEMENT, REMOVING AND INSTALLING»(/audi/a4/b6-2000-2006/remont/automatic-hvac-system/#air-conditioning__dust-and-pollen-filter-element-removing) Follow filter change intervals See «DUST AND POLLEN FILTER, REPLACING»(/audi/a4/b6-2000-2006/remont/procedures/#maintenance__dust-and-pollen-filter-replacing) Different versions (with or without active carbon filter element, see «DUST AND POLLEN FILTER WITH ACTIVE-CARBON-FILTER ELEMENT»(/audi/a4/b6-2000-2006/remont/automatic-hvac-system/#air-conditioning__dust-and-pollen-filter-with-active-carbon-filter) )
4. Threaded connection in refrigerant line (with restrictor) Only open the threaded connection when the refrigerant has been discharged from the A/C system.
5. Service connection High pressure side For measuring, discharging and charging Cap with seal, always re-install after using service valve
6. Sensor for air quality - G238- Function, see «FUNCTION»(/audi/a4/b6-2000-2006/remont/communication-devices/#on-board-diagnostic-obd) Checking, see «SENSOR FOR AIR QUALITY -G238-, CHECKING»(/audi/a4/b6-2000-2006/remont/communication-devices/#on-board-diagnostic-obd) Removing and installing, see «SENSOR FOR AIR QUALITY -G238-, REMOVING AND INSTALLING»(/audi/a4/b6-2000-2006/remont/automatic-hvac-system/#air-conditioning__sensor-for-air-quality-g238-removing)
7. Heated Windshield Control Module -J505- Function, see «WINDSHIELD DEFROSTER, FUNCTION»(/audi/a4/b6-2000-2006/remont/communication-devices/#on-board-diagnostic-obd__windshield-defroster-function) Disabling, see «WINDSHIELD DEFROSTER, DISABLING»(/audi/a4/b6-2000-2006/remont/communication-devices/#on-board-diagnostic-obd__windshield-defroster-disabling) .
8. Accumulator Only remove when the refrigerant has been discharged from the A/C system Removing and installing, see «ACCUMULATOR, REMOVING AND INSTALLING»(/audi/a4/b6-2000-2006/remont/automatic-hvac-system/#air-conditioning)
9. Coolant FC (Fan Control) Control Module -J293- 2) The request to switch on the coolant fan is transmitted to the Engine Control Module (ECM) by the A/C control head -E87- via the CAN-bus system. Switches the coolant fans gradually to desired output performance. Installed in various versions on different locations depending on vehicle equipment. Read Measuring Value Block, see «READ MEASURING VALUE BLOCK (FUNCTION 08)»(/audi/a4/b6-2000-2006/remont/communication-devices/#on-board-diagnostic-obd__read-measuring-value-block-function-08) (display group 014) See appropriate System Wiring Diagrams article. See VAS 5051 Vehicle Diagnostic Testing and Information System for more information.
10. Condenser Only remove when the refrigerant has been discharged from the A/C system, see «A/C REFRIGERANT SYSTEM (R-134A), DISCHARGING»(/audi/a4/b6-2000-2006/remont/automatic-hvac-system/#air-conditioning__ac-refrigerant-system-r-134a-discharging) Refrigerant lines, removing and installing, see «REFRIGERANT LINES FOR CONDENSER, REMOVING AND INSTALLING»(/audi/a4/b6-2000-2006/remont/automatic-hvac-system/#air-conditioning) Condenser removing and installing, see «CONDENSER, REMOVING AND INSTALLING»(/audi/a4/b6-2000-2006/remont/automatic-hvac-system/#air-conditioning)
11. Outside Air Temperature Sensor -G17- Removing Disconnect harness connector on temperature sensor and unclip from air guide bracket See «BUMPERS - EXCEPT CABRIOLET»(/audi/a4/b6-2000-2006/remont/exterior-body-panels/#bumpers-except-cabriolet) or «BUMPERS - CABRIOLET»(/audi/a4/b6-2000-2006/remont/exterior-body-panels/#bumpers-cabriolet) Resistance values, see «TEMPERATURE DEPENDING RESISTANCE VALUES OF SENSOR/SENDER»(/audi/a4/b6-2000-2006/remont/communication-devices/#on-board-diagnostic-obd__temperature-depending-resistance-values-of-sensor) The measuring value of Outside Air Temperature Sensor -G17- is evaluated by the instrument cluster control module and transmitted to A/C control head -E87- via the CAN-bus comfort system. See VAS 5051 Vehicle Diagnostic Testing and Information System for more information.
12. A/C Compressor Regulator Valve -N280- 1,2) Checking activation and function, see «ACTIVATION FOR A/C COMPRESSOR REGULATOR VALVE -N280»(/audi/a4/b6-2000-2006/remont/communication-devices/#on-board-diagnostic-obd)
13. Compressor Compressor from bracket, removing and installing, see «COMPRESSOR, REMOVING AND INSTALLING FROM BRACKET»(/audi/a4/b6-2000-2006/remont/automatic-hvac-system/#air-conditioning) Refrigerant lines on compressor, removing and installing, see «REFRIGERANT LINES ON COMPRESSOR, REMOVING AND INSTALLING»(/audi/a4/b6-2000-2006/remont/automatic-hvac-system/#air-conditioning__refrigerant-lines-on-compressor-removing-and) Compressor, removing and installing, see «COMPRESSOR, REMOVING AND INSTALLING (FOR VEHICLES WITH A 4 OR 6 CYL. ENGINE)»(/audi/a4/b6-2000-2006/remont/automatic-hvac-system/#air-conditioning) The compressor construction differs depending on engine (4, 6 or 8 cyl. gasoline engine) Different compressor types are installed depending on country variants (e.g. Denso, model designation 7SEU series USA); See Parts department. Ribbed belt, removing and installing See «RIBBED BELT, REMOVING AND INSTALLING»(ref-197056-S06598932702005101100000) for the 1.8L engine, or «RIBBED BELT, REMOVING AND INSTALLING»(ref-197058-S42630607092005101100000) for the 3.0L engine. Removing belt pulley, see «BELT PULLEY/DRIVE UNIT OF COMPRESSOR, REPLACING»(/audi/a4/b6-2000-2006/remont/automatic-hvac-system/#air-conditioning) Checking, replacing drive unit-compressor, see «COMPRESSOR DRIVE UNIT, CHECKING, REPLACING»(/audi/a4/b6-2000-2006/remont/automatic-hvac-system/#air-conditioning__compressor-drive-unit-checking-replacing)
14. High Pressure Sensor of A/C system -G65- 1) Function, removing and installing, see «HIGH PRESSURE SENSOR -G65-, REMOVING AND INSTALLING»(/audi/a4/b6-2000-2006/remont/automatic-hvac-system/#air-conditioning__high-pressure-sensor-g65-removing-and) The measuring value of the sensor is displayed in function "Read Measuring Value Block" by A/C Control Head - E87-. See «TEST STEPS 5 TO 9»(/audi/a4/b6-2000-2006/remont/communication-devices/#on-board-diagnostic-obd) and «PRESSURE SIGNAL FROM HIGH PRESSURE SENSOR -G65»(/audi/a4/b6-2000-2006/remont/communication-devices/#on-board-diagnostic-obd__pressure-signal-from-high-pressure-sensor) .
15. Air extraction vents Sealing flaps on air extraction vent must be able to 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, see «AIR EXTRACTION VENT, CHECKING»(/audi/a4/b6-2000-2006/remont/automatic-hvac-system/#air-conditioning__air-extraction-vent-checking)

Dust and pollen filter element, removing and installing

Note. Change interval for dust and pollen filter: See Additional Information, Maintenance Schedule for appropriate model year The filter element exists in various versions (with or without active-carbon insert which functions as an integrated odor filter) The filter is located beneath the fresh air plenum cover on the right side.

1. Remove plenum cover.
2. Unclip cover -B- and pull forward.
3. Remove dust and pollen filter -C- from housing.

Notes for installation

1. Observe flow direction "arrow" -D- when inserting filter in filter frame.
2. Make sure cover -B- is correctly installed, cover must clip in at both notches -A-, otherwise water can run onto dust and pollen filter into air conditioner.

Dust and pollen filter with active-carbon-filter element

1. With the implementation of the Sensor for air quality -G238- (see «SENSOR FOR AIR QUALITY -G238»(/audi/a4/b6-2000-2006/remont/communication-devices/#on-board-diagnostic-obd) ), vehicles that are equipped with this sensor have only dust- and pollen filter with additional active-carbon filter element installed.
2. The active-carbon filter element continues to function as a dust- and pollen filter, however in addition the active-carbon filter can also filter out gaseous pollutants e.g. ozone, benzene, nitrogen dioxide.
3. The task of the active carbon filter element is to store (catch) the gaseous pollutants of the incoming air, until the fresh air flap is closed and the climate control system operates in recirculating mode. The change over from fresh to recirculating mode occurs via the A/C control head, as soon as the air quality sensor detects gaseous pollutants in the ambient air (the "automatic recirculating" mode must be selected).
4. The active-carbon layer in the dust- and pollen filter reacts differently to various pollutants in the air. Certain pollutants bond permanently in the active-carbon layer. Others are being converted into innocuous bonds like in a catalytic converter. For the rest the active-carbon works like condenser (capacitor). With increasing load pollutants are being absorbed, until a certain saturation is reached. If the amount of pollutants decreases, the active-carbon layer continuously releases the absorbed particles.
5. Under the following operating conditions the dust- and pollen filter must be replaced earlier than required, because a certain amount of pollutant particles are permanently bonded to the active-carbon layer: If vehicles is driven in areas with strong air pollution. If vehicle is predominantly driven with the "automatic recirculating" mode switched off. On vehicles without air quality sensor and therefore without "automatic recirculating" mode.
6. If possible, vehicles with climate control using the air quality sensor should always be operated in "automatic recirculating" mode. However, if it is necessary to switch this mode off, the following must be observed: The active carbon layer in the dust- and pollen filter is saturated after a certain time. A saturated filter can no longer absorb pollutants and the pollutants can flow through undisturbed.
7. The most important task of the dust- and pollen filter and air quality sensor is to keep the load peaks out from the passenger compartment. For this the following must be observed: If a vehicle is driven in an area with relative clean ambient air (with little gaseous pollutants in the air), the change over from fresh into recirculating mode occurs at different point in time as in an area with higher concentration of pollutants (e.g. industrial area). The change-over from fresh- to recirculating mode always occurs, when the pollutant-load increases (e.g. when driving to through an exhaust cloud of a Diesel truck).
8. The active-carbon filter can be installed in all vehicles (also in vehicles without air quality sensor). The same limitations apply to these vehicles as on climate control systems with the "automatic recirculation" mode switched off.

Sensor for air quality -G238-, removing and installing

Note. The Sensor for air quality -G238- is a highly sensitive electronic component that can be damaged if it comes in direct contact with solvents, fuels or chemicals (e.g. impurities may enter through area -A-). Do not install sensors that were previously improperly stored (e.g. in tool boxes etc.). Do not store removed sensors in areas that are contaminated with solvents, fuels and certain other chemicals (fluids or gases). The sensor for air quality is in different housings, version "1" was installed at beginning of production. This sensor was replaced in a running change to version "2", however it has the same function.

Removing and installing

1. Remove plenum cover.

Version "1"

1. Disconnect harness connector -A- from sensor.
2. Remove bolt -B- and remove sensor.

Terminal assignment in connector -A

The following list pertains to see scheme 33.

1. B+ (terminal "15")
2. Minus (terminal "31")
3. Signal wire to A/C Control Head -E87- (square wave signal cannot be measured)
4. not assigned

Version "2"

1. Disconnect harness connector -A- from sensor.
2. Disengage locking mechanism -B- and push sensor -C- down.

Terminal assignment in connector -A

The following list pertains to see scheme 34.

1. B+ (Terminal "15")
2. Minus (Terminal "31"
3. Signal wire to A/C- control head -E87- (square wave signal cannot be measured)

Air extraction vent, checking

1. Check ventilation channels to both ventilation frames -A- for throughput (left and right). Sealing lips -B- in air extraction outlets -A- must move freely and close by themselves. Plugged channel may cause window to fog up

Note. In this illustration the air extraction frame is shown on a sedan with the rear bumper removed. Avant models have an air extraction frame with a different construction installed. For the forced ventilation two ventilation frames are installed (left and right) In order for the passenger compartment ventilation to function properly, the vent openings in the luggage compartment trim must not be closed.

Components in passenger compartment

Note. For descriptions of the various vents in the dash panel, see INSTRUMENT PANEL VENTS AND AIR DUCTS .

The following list pertains to see scheme 37 and see scheme 38.

1. Left Vent Temperature Sensor -G150- 1) Removing and installing, see «LEFT VENT TEMPERATURE SENSOR -G150-, REMOVING AND INSTALLING»(/audi/a4/b6-2000-2006/remont/automatic-hvac-system/#air-conditioning) .
2. Data Link Connector (DLC) Carry out On Board Diagnostic for air conditioner. See «AUTOMATIC CLIMATE CONTROL SYSTEM, ON BOARD DIAGNOSTIC (OBD)»(/audi/a4/b6-2000-2006/remont/communication-devices/#on-board-diagnostic-obd) .
3. Instrument cluster With Outside Air Temperature Display - G106 2) The outside temperature transmitted by the A/C control head -E87- is on vehicles with automatic transmission only and displayed with a drive range is engaged. Check temperature sensor measuring values if temperature display is malfunctioning. See «TEMPERATURE DEPENDING RESISTANCE VALUES OF SENSOR/SENDER»(/audi/a4/b6-2000-2006/remont/communication-devices/#on-board-diagnostic-obd__temperature-depending-resistance-values-of-sensor) The measuring value of Outside Air Temperature Sensor -G17- is evaluated by the instrument cluster control module and transmitted to A/C control head -E87- via the CAN-bus comfort system. See VAS 5051 Vehicle Diagnostic Testing and Information System for more information
4. Accelerator pedal The Kick-Down cut-off for A/C Compressor Regulator Valve -N280- occurs via the Engine Control Module (ECM) See VAS 5051 Vehicle Diagnostic Testing and Information System for more information.
5. Actuator for temperature flap left -V158- 2 ) With potentiometer actuator for temperature flap left -G220- 1) Color designation of lever: red Removing and installing, see «ACTUATOR FOR TEMPERATURE FLAP LEFT -V158-, REMOVING AND INSTALLING»(/audi/a4/b6-2000-2006/remont/automatic-hvac-system/#air-conditioning__actuator-for-temperature-flap-left-v158)
6. Heater element for auxiliary heater -Z35- 2) Not applicable in USA
7. Heater core Removing and installing, see «HEATER CORE, REMOVING AND INSTALLING»(/audi/a4/b6-2000-2006/remont/automatic-hvac-system/#air-conditioning)
8. Left Footwell Vent Temperature Sensor - G261- 1) Removing and installing, see «LEFT FOOTWELL VENT TEMPERATURE SENSOR -G261-, REMOVING AND INSTALLING»(/audi/a4/b6-2000-2006/remont/automatic-hvac-system/#air-conditioning__left-footwell-vent-temperature-sensor-g261)
9. Right Footwell Vent Temperature Sensor - G262- 1) Removing and installing, see «RIGHT FOOTWELL VENT TEMPERATURE SENSOR - G262-, REMOVING AND INSTALLING»(/audi/a4/b6-2000-2006/remont/automatic-hvac-system/#air-conditioning__right-footwell-vent-temperature-sensor)
10. A/C control head -E87- Various versions, allocation Removing and installing, see «A/C CONTROL HEAD -E87-, REMOVING AND INSTALLING»(/audi/a4/b6-2000-2006/remont/automatic-hvac-system/#air-conditioning__ac-control-head-e87-removing-and) The Interior Temperature Sensor Fan -V42- and the Instrument Panel Interior Temperature Sensor -G56- are integrated in the A/C control head -E87- Observe additional notes, see «A/C CONTROL HEAD -E87-, REMOVING AND INSTALLING»(/audi/a4/b6-2000-2006/remont/automatic-hvac-system/#air-conditioning__ac-control-head-e87-removing-and) Check coding and code, see «A/C CONTROL HEAD -E87-, CODING (FUNCTION 07)»(/audi/a4/b6-2000-2006/remont/communication-devices/#on-board-diagnostic-obd__ac-control-head-e87-coding-function) Display fields illuminated via LEDs, not replaceable A/C Control Head -E87- can also be referred to as "Climatronic Control Module -J255-" in other repair information
11. Interior Temperature Sensor Fan -V42- 2) Integrated in -E87-, cannot be replaced separately.
12. Instrument Panel Interior Temperature Sensor - G56- Integrated in -E87-, cannot be replaced separately.
13. Defroster outlet vent For front windshield Removing and installing See «INSTRUMENT PANEL, REMOVING AND INSTALLING»(/audi/a4/b6-2000-2006/remont/gauges-instrument-panels/#interior-trim-except-cabriolet__instrument-panel-removing-and-installing) (except Cabriolet), or «INSTRUMENT PANEL, REMOVING AND INSTALLING»(/audi/a4/b6-2000-2006/remont/gauges-instrument-panels/#interior-trim-cabriolet) for the Cabriolet
14. Sunlight Photo Sensor - G107- 1) Removing and installing, see «SUNLIGHT PHOTO SENSOR -G107-, REMOVING AND INSTALLING»(/audi/a4/b6-2000-2006/remont/automatic-hvac-system/#air-conditioning)
15. Fresh Air Intake Duct Temperature Sensor - G89- 1) Checking, see «TEMPERATURE SENSOR / SENDER»(/audi/a4/b6-2000-2006/remont/communication-devices/#on-board-diagnostic-obd) Removing and installing, see «FRESH AIR INTAKE DUCT TEMPERATURE SENSOR -G89-, REMOVING AND INSTALLING»(/audi/a4/b6-2000-2006/remont/automatic-hvac-system/#air-conditioning)
16. Recirculation Flap Motor -V113- 2) With potentiometer - Recirculation- Flap Motor Position Sensor - G143- 1) Color designation of lever: blue Removing and installing, see «RECIRCULATION FLAP MOTOR -V113-, REMOVING AND INSTALLING»(/audi/a4/b6-2000-2006/remont/automatic-hvac-system/#air-conditioning)
17. Air Flow Flap Motor - V71- 2) The flaps activated by this motor are fresh air and back pressure flap in one. Only installed in vehicles with left hand steering. With potentiometer - Recirculation- Flap Motor Position Sensor - G113- 1) Color designation of curved washer: light blue Removing and installing, see «DEFROSTER FLAP MOTOR -V107-, REMOVING AND INSTALLING»(/audi/a4/b6-2000-2006/remont/automatic-hvac-system/#air-conditioning)
18. Right Vent Temperature Sensor -G151- 1) Removing and installing, see «RIGHT VENT TEMPERATURE SENSOR -G151-, REMOVING AND INSTALLING»(/audi/a4/b6-2000-2006/remont/automatic-hvac-system/#air-conditioning) .
19. Control module for fresh air blower -J126- and Fresh Air Blower -V2- 2) Removing and installing, see «CONTROL MODULE FOR FRESH AIR BLOWER -J126- AND FRESH AIR BLOWER -V2-, REMOVING AND INSTALLING»(/audi/a4/b6-2000-2006/remont/automatic-hvac-system/#air-conditioning) The Control module for fresh air blower -J126- is integrated in the Fresh Air Blower -V2-, and cannot be replaced separately.
20. Connection for air guide for cooling the glove compartment Vehicles without glove compartment cooling have a plug installed (see illustration). Components for glove compartment cooling: See «INTERIOR EQUIPMENT - EXCEPT CABRIOLET»(/audi/a4/b6-2000-2006/remont/mirrors/#interior-equipment-except-cabriolet) or «INTERIOR EQUIPMENT - CABRIOLET»(ref-197209) . Removing and installing, see «AIR GUIDE CONNECTION FOR GLOVE COMPARTMENT COOLING, REMOVING AND INSTALLING»(/audi/a4/b6-2000-2006/remont/automatic-hvac-system/#air-conditioning__air-guide-connection-for-glove-compartment)
21. Evaporator Vent Temperature Sensor - G263- 1) Removing and installing, see «EVAPORATOR VENT TEMPERATURE SENSOR -G263-, REMOVING AND INSTALLING»(/audi/a4/b6-2000-2006/remont/automatic-hvac-system/#air-conditioning)
22. Central Air Flap Motor -V70- 2) Central Flap Motor Position Sensor -G112- 1) Color designation of curved washer: white Removing and installing, see «CENTRAL AIR FLAP MOTOR -V70-, REMOVING AND INSTALLING»(/audi/a4/b6-2000-2006/remont/automatic-hvac-system/#air-conditioning)
23. Defroster Flap Motor -V107- 2) With Defroster Flap Motor Position Sensor -G135- 1) Color designation of lever: dark green Removing and installing, see «DEFROSTER FLAP MOTOR -V107-, REMOVING AND INSTALLING»(/audi/a4/b6-2000-2006/remont/automatic-hvac-system/#air-conditioning)
24. Actuator for temperature flap right -V159- 2 Potentiometer-actuator for temperature flap right -G221- 1) Color designation of lever: violet Removing and installing, see «ACTUATOR FOR TEMPERATURE FLAP RIGHT -V159-, REMOVING AND INSTALLING»(/audi/a4/b6-2000-2006/remont/automatic-hvac-system/#air-conditioning__actuator-for-temperature-flap-right-v159)
25. Evaporator housing drain Checking, see «EVAPORATOR HOUSING DRAIN, CHECKING»(/audi/a4/b6-2000-2006/remont/automatic-hvac-system/#air-conditioning) Removing and installing, see «EVAPORATOR HOUSING DRAIN, REMOVING AND INSTALLING»(/audi/a4/b6-2000-2006/remont/automatic-hvac-system/#air-conditioning)
26. Evaporator housing drain valve Checking, see «EVAPORATOR HOUSING DRAIN, CHECKING»(/audi/a4/b6-2000-2006/remont/automatic-hvac-system/#air-conditioning) Removing and installing, see «EVAPORATOR HOUSING DRAIN, REMOVING AND INSTALLING»(/audi/a4/b6-2000-2006/remont/automatic-hvac-system/#air-conditioning)
27. Air conditioning unit with evaporator Removing and installing, see «HEATING AND A/C UNIT, REMOVING AND INSTALLING»(/audi/a4/b6-2000-2006/remont/automatic-hvac-system/#air-conditioning) Disassembling and assembling, see «HEATING AND A/C UNIT, COMPONENT OVERVIEW»(/audi/a4/b6-2000-2006/remont/automatic-hvac-system/#air-conditioning__heating-and-ac-unit-component-overview) . Only remove when the refrigerant has been discharged from the A/C system, see «A/C REFRIGERANT SYSTEM (R-134A), DISCHARGING»(/audi/a4/b6-2000-2006/remont/automatic-hvac-system/#air-conditioning__ac-refrigerant-system-r-134a-discharging)

A/C control head -E87-, removing and installing

1. A/C control head -E87-, removing and installing, see «A/C CONTROL HEAD -E87-, REMOVING AND INSTALLING»(/audi/a4/b6-2000-2006/remont/automatic-hvac-system/#air-conditioning) .

Note. Follow coding procedure exactly when replacing an A/C control head -E87- A/C Control Head -E87- varies for vehicles with and without radio navigation system (or a radio with a large control panel), with and without switch for heated seats, without and with sensor for air quality (with "Off button" or with "Automatic recirculated air" button). Therefore, note index of part number. After installation Initiate basic setting for A/C system according to procedure. See BASIC SETTING (FUNCTION 04) . The A/C Compressor Regulator Valve -N280- will not be activated if a new A/C control head -E87- was installed and the basic setting was not carried out, and the compressor cut-off condition "6" in measuring value block "2" is displayed during the on board diagnostic of the A/C system. The selected functions are displayed by illuminated LEDs in the various buttons of the A/C control head -E87-. The Instrument Panel Interior Temperature Sensor -G56-, Interior Temperature Sensor Fan -V42- and the switch for the heated rear window (and potentiometers for the heated seats) are integrated into this version of A/C control head - E87- and cannot be replaced separately. After replacing A/C Control Head -E87- always: - -Check coding of A/C Control Head -E87-. See A/C CONTROL HEAD -E87-, CODING (FUNCTION 07) - -Initiate basic setting. See BASIC SETTING (FUNCTION 04) . - -Check DTC memory. See DIAGNOSTIC TROUBLE CODE (DTC) MEMORY, CHECKING (FUNCTION 02) . The coding of the basic settings (e.g. country variants) of the A/C control head -E87- occurs on this vehicle through the instrument cluster. The data is transmitted to the A/C control head -E87- via the CAN-bus comfort system, the currently valid coding is shown in the measuring value block. See READ MEASURING VALUE BLOCK (FUNCTION 08) . The direct coding input into the A/C control head -E87- applies to certain options (e.g. heated front windshield). See VAS 5051 Vehicle Diagnostic Testing and Information System for more information. The temperature display of the A/C control head -E87- in °C or °F is transmitted by the instrument cluster and is determined by the coding of the instrument cluster. The display unit can be changed by pressing the "Recirculated air" button and the "Temperature +" button on left side simultaneously for longer than 2 second. The A/C control head -E87- then sends the outside temperature with the changed unit to the instrument cluster, the instrument cluster accepts this change, the display in the A/C control head -E87- and the outside temperature display in the instrument cluster occurs in same unit. The change-over of the A/C control head -E87- is valid for all ignition keys. As of April 2002, there will be a running change to installing A/C Control Head -E87- with part numbers from index "H" (with hardware/software version from "XX15"). With the -E87-, temperature control is designed for slightly cooler performance for passenger compartment. For vehicles as of model year 2003, only A/C Control Head -E87- with part number from index "H" is/will be installed. A/C Control Head -E87- can also be referred to as "Climatronic Control Module -J255-" in other repair information. As of model year 2003, A/C Control Head -E87- with part number as of index "H" (with hard-/software version as of "XX16") will be implemented as a running change. These A/C Control Heads -E87- differ from the software version as of "XX15" in the following points: The temperature regulation for the passenger compartment in the Audi Cabriolet and opened convertible top was changed and therefore was adjusted somewhat lower. The temperature adjustment range was expanded, the lowest temperature of 16 ° C can now be selected (instead of previous 18 °C). For the Audi Cabriolet, different settings for closed and open convertible top are stored in the A/C Control Head -E87-. When opening and closing the convertible top, the A/C Control Head -E87- independently changes the setting to the value which was last adjusted during closed or open convertible top. If a number is displayed in A/C Control Head -E87- display, check DTC memory of -E87- (the number "60" refers to a malfunction at Interior Temperature Sensor Fan -V42-).

On vehicles without Radio-Navigation system or radio with large control panel

1. Reach from below in the center console and loosen A/C control head -E87- from center console (if -E87- is difficult to remove, proceed as on vehicles with Radio-Navigation system). On vehicles without Radio-Navigation system or radio with large control panel
2. Remove radio or radio-navigation system: See «RADIO SYSTEM - EXCEPT CABRIOLET»(/audi/a4/b6-2000-2006/remont/entertainment-systems/#radio-system-except-cabriolet) or «RADIO SYSTEM - CABRIOLET»(/audi/a4/b6-2000-2006/remont/entertainment-systems/#radio-system-cabriolet)
3. Reach through the opening and push the A/C control head -E87- toward the rear out of center console.

Note. The A/C control head -E87- is secured in the center console with 4 retaining clips -A-. If Instrument Panel Interior Temperature Sensor -G56- sends incorrect measuring values, check intake grill trim on the A/C control head -E87-, the grill should not be obstructed and check the function of Interior Temperature Sensor Fan -V42-. When replacing an A/C control head observe exact allocation (e.g. with or without switch for heated seats): An A/C control head for vehicles without radio-navigation system -A- has an additional trim -B- with 2 screws -C- available.

1. Unlock connectors -A- to -D- and -F- and disconnect them by pressing the unlocking lugs.
2. Remove bolts -C- and slide trim -B- to the right and remove from A/C Control Head -E87- -A- (if installed).

1. Installation is in reverse order of removal.

Air guide connection for glove compartment cooling, removing and installing

Note. The air conditioner has an opening -A- for the connection of the air guide -B- to the glove compartment. The cooled air is directed through this air guide into the glove compartment. On vehicles without glove compartment cooling the opening -A- is closed with a plug -C-.

1. Remove vent -D- (this vent is fastened to air guide -B-.)
2. Remove glove compartment: See «GLOVE COMPARTMENT, REMOVING AND INSTALLING»(/audi/a4/b6-2000-2006/remont/mirrors/#interior-equipment-except-cabriolet__glove-compartment-removing-and-installing) (except Cabriolet), or «GLOVE COMPARTMENT, ASSEMBLY OVERVIEW»(ref-197209-S32533520222005101300000) for the Cabriolet
3. Turn air guide -B- approx. quarter turn to the left and remove from air conditioner.

Installation is reverse of removal.

1. Remove glove compartment: For Cabriolet models, see «GLOVE COMPARTMENT, REMOVING AND INSTALLING»(/audi/a4/b6-2000-2006/remont/mirrors/#interior-equipment-except-cabriolet__glove-compartment-removing-and-installing) . For models other than Cabriolet, see «GLOVE COMPARTMENT, ASSEMBLY OVERVIEW»(ref-197209-S32533520222005101300000) .
2. Disconnect connector -A-.
3. Remove lower A-pillar trim: See «LOWER A-PILLAR TRIM, ASSEMBLY OVERVIEW»(/audi/a4/b6-2000-2006/remont/gauges-instrument-panels/#interior-trim-except-cabriolet__lower-a-pillar-trim-assembly-overview) (except Cabriolet), or «LOWER A-PILLAR TRIM, ASSEMBLY OVERVIEW»(/audi/a4/b6-2000-2006/remont/gauges-instrument-panels/#interior-trim-cabriolet__lower-a-pillar-trim-assembly-overview) for the Cabriolet.
4. Loosen cable tie -B
5. Remove bolts -A-.
6. Tilt carpet carefully toward back.
7. Press sound insulation mat aside, until rear screw -C- is reachable.
8. Unscrew bolts -C-.
9. Press sound insulation mat aside and pull fresh air blower -D- out of air conditioner.

Note. The Control module for fresh air blower -J126- is integrated in the Fresh Air Blower -V2-, and cannot be replaced separately. Observe correct seating position when installing the fresh air blower into the air conditioner.

Installation is the reverse of removal.

1. Remove A pillar trim on drivers side. See «LOWER A-PILLAR TRIM, ASSEMBLY OVERVIEW»(/audi/a4/b6-2000-2006/remont/gauges-instrument-panels/#interior-trim-except-cabriolet__lower-a-pillar-trim-assembly-overview) (except Cabriolet). For the Cabriolet, see «LOWER A-PILLAR TRIM, ASSEMBLY OVERVIEW»(/audi/a4/b6-2000-2006/remont/gauges-instrument-panels/#interior-trim-cabriolet__lower-a-pillar-trim-assembly-overview) .
2. Turn sensor -B- 90° (1/4 turn) and pull out of air guide channel.
3. Disconnect harness connector -A-.

Installation is the reverse of removal.

1. Remove passenger side -A- pillar trim (if the sensor cannot be removed, additionally remove glove compartment).
2. Remove glove box. See «GLOVE COMPARTMENT, REMOVING AND INSTALLING»(/audi/a4/b6-2000-2006/remont/mirrors/#interior-equipment-except-cabriolet__glove-compartment-removing-and-installing) (except Cabriolet). For the Cabriolet, see «GLOVE COMPARTMENT, ASSEMBLY OVERVIEW»(ref-197209-S32533520222005101300000) .
3. Disconnect connector -A-.
4. Turn sensor -B- 90° (1/4 turn) and pull out of air guide channel.

Installation is the reverse of removal.

1. Remove glove compartment: See «GLOVE COMPARTMENT, REMOVING AND INSTALLING»(/audi/a4/b6-2000-2006/remont/mirrors/#interior-equipment-except-cabriolet__glove-compartment-removing-and-installing) (except Cabriolet). For the Cabriolet, see «GLOVE COMPARTMENT, ASSEMBLY OVERVIEW»(ref-197209-S32533520222005101300000) .
2. Disconnect connector -A-.
3. Turn sensor -B- 90° (1/4 turn) and pull out of air conditioning unit.

Installation is the reverse of removal.

Left Footwell Vent Temperature Sensor -G261-, removing and installing

Note. Observe connector arrangement to both sensors -G261- and -G262- (mix-up alert)

1. Remove A/C Control Head -E87-, see «A/C CONTROL HEAD -E87-, REMOVING AND INSTALLING»(/audi/a4/b6-2000-2006/remont/automatic-hvac-system/#air-conditioning) .
2. Reach through opening for the A/C control head and disconnect connector -A-.
3. Turn vent temperature sensor -B- approx. 90° in direction of arrow.
4. Remove vent temperature sensor out of air conditioner.

Installation is the reverse of removal.

Right Footwell Vent Temperature Sensor - G262-, removing and installing

Note. Observe connector arrangement to both sensors -G261- and -G262- (mix-up alert)

1. Remove A/C Control Head -E87-, see «A/C CONTROL HEAD -E87-, REMOVING AND INSTALLING»(/audi/a4/b6-2000-2006/remont/automatic-hvac-system/#air-conditioning) .
2. Reach through opening for the A/C control head and disconnect connector -A-.
3. Turn vent temperature sensor -B- approx. 90° in direction of arrow.
4. Remove vent temperature sensor out of air conditioner.

Installation is the reverse of removal.

1. Carefully pry out cover -A- in direction of arrow out of defroster vent for front windshield.
2. Unscrew screw -B-.
3. Take sunlight photo sensor out of defroster vent for front windshield.
4. Secure connector -C- from falling into instrument panel and disconnect from sunlight photo sensor.

Installation is the reverse of removal.

1. Remove glove compartment, lower A-pillar trim and passenger-side floor mat: See «INTERIOR EQUIPMENT - EXCEPT CABRIOLET»(/audi/a4/b6-2000-2006/remont/mirrors/#interior-equipment-except-cabriolet) . For the Cabriolet, see «INTERIOR EQUIPMENT - CABRIOLET»(ref-197209) .
2. Tilt carpet carefully toward back.
3. Loosen clamp -A
4. Pull evaporator drain hose -B- with valve -C- out of vehicle floor.
5. Remove evaporator housing drain with valve.

1. Check distance of sound insulation mat in area of opening -E- to vehicle floor (the sound insulation mat should not touch the evaporator drain valve).
2. Check evaporator drain valve -C-, the valve should not clotted with wax and under coating.
3. Check evaporator drain hose -B- for soiling and clean before installing.
4. Install evaporator drain valve -C- completely as illustrated (if necessary use soap as lubricant).
5. Check evaporator drain hose -B-, hose should not be twisted or pinched and must be installed in the designated groove in floor mat.
6. Loosen clamp -A-.
7. Install all components in reverse order.

Scheme 5

1. Check routing of evaporator housing drain hose, the hose should not be twisted or pinched.
2. Remove evaporator housing drain valve and evaporator housing drain hose. See «EVAPORATOR HOUSING DRAIN, REMOVING AND INSTALLING»(/audi/a4/b6-2000-2006/remont/automatic-hvac-system/#air-conditioning) .
3. Check distance of sound insulation mat in area of opening -E- to vehicle floor (the sound insulation mat should not touch the evaporator drain valve).
4. Check evaporator drain valve -C-, the valve should not clotted with wax and undercoating. NOTE: The evaporator housing drain valve -C- has no flap, the function of the flap is carried out via the spiral in the valve. Check evaporator drain hose -B- for soiling (observe oval cross section of hose -D-) and clean if necessary. Check evaporator housing drain of air conditioner -F- (for example using a wire) for soiling and clean if necessary. If passenger compartment is moist: Check air extraction outlets in passenger compartment (via luggage compartment), see «AIR EXTRACTION VENT, CHECKING»(/audi/a4/b6-2000-2006/remont/automatic-hvac-system/#air-conditioning__air-extraction-vent-checking) . Check recognition signal of windshield wiper operation on A/C control head -E87-. See «DISPLAY GROUP 014»(/audi/a4/b6-2000-2006/remont/communication-devices/#on-board-diagnostic-obd__display-group-014) and «DISPLAY GROUP 018»(/audi/a4/b6-2000-2006/remont/communication-devices/#on-board-diagnostic-obd__display-group-018) . Check dust and pollen filter for soiling and the cover for correct installation. See «DUST AND POLLEN FILTER ELEMENT, REMOVING AND INSTALLING»(/audi/a4/b6-2000-2006/remont/automatic-hvac-system/#air-conditioning__dust-and-pollen-filter-element-removing) . Check various positioning motors and the pertaining levers, pay particular attention to Air Flow Flap Motor -V71- and Recirculation Flap Motor -V113- and the pertaining levers Check measuring value of Evaporator Vent Temperature Sensor -G263-. See «READ MEASURING VALUE BLOCK (FUNCTION 08)»(/audi/a4/b6-2000-2006/remont/communication-devices/#on-board-diagnostic-obd__read-measuring-value-block-function-08) . - -If the measuring value of the sensor is too low for the operating requirements described by the customer (at an ambient temperature above 0°C, is colder than 0°C for an extended period of time) observe notes for checking the cooling performance. See «A/C REFRIGERANT SYSTEM COOLING PERFORMANCE, TESTING»(/audi/a4/b6-2000-2006/remont/automatic-hvac-system/#air-conditioning) . - -If the measuring value of the sensor is too high for the operating requirements described by the customer (higher than e.g. 10°C even though the A/C system is functioning properly) check Evaporator Vent Temperature Sensor -G263- (the condenser can ice over due to an incorrect measuring value).

Adapter cable, modifying to activate positioning motors

1. Connect a 0.25 mm 2 wire across terminals "5" and "6" of connector -A- (part number 8D0 972 706). CAUTION: Part numbers are listed here for reference only. Always check with your Parts department for the latest information.
2. Connect the other end of the each wire to a commercially available connector -B-.

1. Remove glove compartment: See «GLOVE COMPARTMENT, REMOVING AND INSTALLING»(/audi/a4/b6-2000-2006/remont/mirrors/#interior-equipment-except-cabriolet__glove-compartment-removing-and-installing) (except Cabriolet). For the Cabriolet, see «GLOVE COMPARTMENT, ASSEMBLY OVERVIEW»(ref-197209-S32533520222005101300000) .
2. Disconnect connector -A-.
3. Unscrew bolts -B-.
4. Loosen positioning motor from bracket -C-.
5. Loosen lever -D- of positioning motor from connection rod -E-.

Note. The lever on the positioning motor is color coded, the lever on Central Air Flap Motor -V70- is dark green.

Install all removed parts in reverse order, observe the following while doing so

1. Install the wiring harness so that it cannot come in contact with any moving parts (e.g. the actuating arm of the positioning motor).
2. Check DTC memory (see «DIAGNOSTIC TROUBLE CODE (DTC) MEMORY, CHECKING (FUNCTION 02)»(/audi/a4/b6-2000-2006/remont/communication-devices/#on-board-diagnostic-obd__diagnostic-trouble-code-dtc-memory-checking) ) and erase DTC memory (see «DIAGNOSTIC TROUBLE CODE (DTC) MEMORY, ERASING (FUNCTION 05)»(/audi/a4/b6-2000-2006/remont/communication-devices/#on-board-diagnostic-obd__diagnostic-trouble-code-dtc-memory-erasing) ). Initiate basic setting (see «BASIC SETTING (FUNCTION 04)»(/audi/a4/b6-2000-2006/remont/communication-devices/#on-board-diagnostic-obd__basic-setting-function-04) .

Note. The function of the positioning motor can be checked for example: Connect both terminals "5" and "6" in positioning motor connector to 12V (DC), the motor moves in one direction until stop, the direction of rotation changes by reversing B+ and Ground. Use adapter cable for this. See ADAPTER CABLE, MODIFYING TO ACTIVATE POSITIONING MOTORS .

Actuator for temperature flap right -V159-, removing and installing

Note. This positioning motor moves two flaps, these flaps are connected in the air conditioner via a coupling rod (not visible from outside), see COUPLING ELEMENT BETWEEN TEMPERATURE FLAPS "1" AND "2" . In the event of a temperature control complaint, the connection between the flaps can be checked with the heater core removed but without removing the air conditioner (for visual inspection check flap through the opening) Reach through hole of heater core into air conditioner and move flaps via the external actuator lever.

1. Remove glove compartment: See «GLOVE COMPARTMENT, REMOVING AND INSTALLING»(/audi/a4/b6-2000-2006/remont/mirrors/#interior-equipment-except-cabriolet__glove-compartment-removing-and-installing) (except Cabriolet). For the Cabriolet, see «GLOVE COMPARTMENT, ASSEMBLY OVERVIEW»(ref-197209-S32533520222005101300000) .
2. Disconnect connector -A-.
3. Unscrew bolts -B-.
4. Loosen lever -C- of positioning motor from connection rod -D

Note. The lever on the positioning motor is color coded, the lever on Actuator for temperature flap right -V159- is violet.

Install all removed parts in reverse order, observe the following while doing so

1. Install the wiring harness so that it cannot come in contact with any moving parts (e.g. the actuating arm of the positioning motor).
2. Check DTC memory (see «DIAGNOSTIC TROUBLE CODE (DTC) MEMORY, CHECKING (FUNCTION 02)»(/audi/a4/b6-2000-2006/remont/communication-devices/#on-board-diagnostic-obd__diagnostic-trouble-code-dtc-memory-checking) ) and erase DTC memory (see «DIAGNOSTIC TROUBLE CODE (DTC) MEMORY, ERASING (FUNCTION 05)»(/audi/a4/b6-2000-2006/remont/communication-devices/#on-board-diagnostic-obd__diagnostic-trouble-code-dtc-memory-erasing) . Initiate basic setting (see «BASIC SETTING (FUNCTION 04)»(/audi/a4/b6-2000-2006/remont/communication-devices/#on-board-diagnostic-obd__basic-setting-function-04) .

Note. The function of the positioning motor can be checked for example: Connect both terminals "5" and "6" in positioning motor connector to 12V (DC), the motor moves in one direction until stop, the direction of rotation changes by reversing B+ and Ground. Use adapter cable for this. See ADAPTER CABLE, MODIFYING TO ACTIVATE POSITIONING MOTORS .

Actuator for temperature flap left -V158-, removing and installing

Note. This positioning motor moves two flaps, these flaps are connected in the air conditioner via a coupling rod (not visible from outside), see COUPLING ELEMENT BETWEEN TEMPERATURE FLAPS "1" AND "2" . In the event of a temperature control complaint, the connection between the flaps can be checked with the heater core removed but without removing the air conditioner (for visual inspection check flap through the opening). Reach through hole of heater core into air conditioner and move flaps via the external actuator lever.

1. Remove driver side storage compartment. See «DRIVER-SIDE STORAGE COMPARTMENT (WITH AND WITHOUT KNEE BOLSTER), ASSEMBLY OVERVIEW»(/audi/a4/b6-2000-2006/remont/mirrors/#interior-equipment-except-cabriolet__driver-side-storage-compartment-with-and-without) (except Cabriolet). For the Cabriolet, see «DRIVER'S STORAGE COMPARTMENT (VEHICLES WITH AND WITHOUT KNEE BOLSTER), ASSEMBLY OVERVIEW»(ref-197209-S29048734852005101300000) .
2. Disconnect connector -A-.
3. Unscrew bolts -B-.
4. Loosen lever -C- of positioning motor from connection rod -D-.

Note. The lever on the positioning motor is color coded, the lever on Actuator for temperature flap left -V158- is red.

Install all removed parts in reverse order, observe the following while doing so

1. Install the wiring harness so that it cannot come in contact with any moving parts (e.g. the actuating arm of the positioning motor).
2. Check DTC memory (see «DIAGNOSTIC TROUBLE CODE (DTC) MEMORY, CHECKING (FUNCTION 02)»(/audi/a4/b6-2000-2006/remont/communication-devices/#on-board-diagnostic-obd__diagnostic-trouble-code-dtc-memory-checking) ) and erase DTC memory (see «DIAGNOSTIC TROUBLE CODE (DTC) MEMORY, ERASING (FUNCTION 05)»(/audi/a4/b6-2000-2006/remont/communication-devices/#on-board-diagnostic-obd__diagnostic-trouble-code-dtc-memory-erasing) . Initiate basic setting (see «BASIC SETTING (FUNCTION 04)»(/audi/a4/b6-2000-2006/remont/communication-devices/#on-board-diagnostic-obd__basic-setting-function-04) .

Note. The function of the positioning motor can be checked for example: Connect both terminals "5" and "6" in positioning motor connector to 12V (DC), the motor moves in one direction until stop, the direction of rotation changes by reversing B+ and Ground. Use adapter cable for this. See ADAPTER CABLE, MODIFYING TO ACTIVATE POSITIONING MOTORS .

1. Remove glove compartment: See «GLOVE COMPARTMENT, REMOVING AND INSTALLING»(/audi/a4/b6-2000-2006/remont/mirrors/#interior-equipment-except-cabriolet__glove-compartment-removing-and-installing) (except Cabriolet). For the Cabriolet, see «GLOVE COMPARTMENT, ASSEMBLY OVERVIEW»(ref-197209-S32533520222005101300000) .
2. Disconnect connector -A-.
3. Unscrew bolts -B-.
4. Remove positioning motor.

Note. The curved washer on the positioning motor is color coded, the lever on Central Air Flap Motor -V70- is white.

1. Place pins -A- and -B- in the groove -C- of curved washer. Install all removed parts in reverse order, observe the following while doing so
2. Install the wiring harness so that it cannot come in contact with any moving parts (e.g. the actuating arm of the positioning motor).
3. Check DTC memory (see «DIAGNOSTIC TROUBLE CODE (DTC) MEMORY, CHECKING (FUNCTION 02)»(/audi/a4/b6-2000-2006/remont/communication-devices/#on-board-diagnostic-obd__diagnostic-trouble-code-dtc-memory-checking) ) and erase DTC memory (see «DIAGNOSTIC TROUBLE CODE (DTC) MEMORY, ERASING (FUNCTION 05)»(/audi/a4/b6-2000-2006/remont/communication-devices/#on-board-diagnostic-obd__diagnostic-trouble-code-dtc-memory-erasing) . Initiate basic setting (see «BASIC SETTING (FUNCTION 04)»(/audi/a4/b6-2000-2006/remont/communication-devices/#on-board-diagnostic-obd__basic-setting-function-04) .

Note. The function of the positioning motor can be checked for example: Connect both terminals "5" and "6" in positioning motor connector to 12V (DC), the motor moves in one direction until stop, the direction of rotation changes by reversing B+ and Ground. Use adapter cable for this. See ADAPTER CABLE, MODIFYING TO ACTIVATE POSITIONING MOTORS .

1. Remove glove compartment: See «GLOVE COMPARTMENT, REMOVING AND INSTALLING»(/audi/a4/b6-2000-2006/remont/mirrors/#interior-equipment-except-cabriolet__glove-compartment-removing-and-installing) (except Cabriolet). For the Cabriolet, see «GLOVE COMPARTMENT, ASSEMBLY OVERVIEW»(ref-197209-S32533520222005101300000) .
2. Disconnect connector -A-.
3. Unscrew bolts -B-.
4. Pull connection element -C- of positioning motor out of recirculated air flap shaft -D

Note. The connecting element on the positioning motor is color coded, on Recirculation Flap Motor -V113- it is blue.

Install all removed parts in reverse order, observe the following while doing so

1. Install the wiring harness so that it cannot come in contact with any moving parts (e.g. the actuating arm of the positioning motor).
2. Check DTC memory (see «DIAGNOSTIC TROUBLE CODE (DTC) MEMORY, CHECKING (FUNCTION 02)»(/audi/a4/b6-2000-2006/remont/communication-devices/#on-board-diagnostic-obd__diagnostic-trouble-code-dtc-memory-checking) ) and erase DTC memory (see «DIAGNOSTIC TROUBLE CODE (DTC) MEMORY, ERASING (FUNCTION 05)»(/audi/a4/b6-2000-2006/remont/communication-devices/#on-board-diagnostic-obd__diagnostic-trouble-code-dtc-memory-erasing) . Initiate basic setting (see «BASIC SETTING (FUNCTION 04)»(/audi/a4/b6-2000-2006/remont/communication-devices/#on-board-diagnostic-obd__basic-setting-function-04) .

Note. The function of the positioning motor can be checked for example: Connect both terminals "5" and "6" in positioning motor connector to 12V (DC), the motor moves in one direction until stop, the direction of rotation changes by reversing B+ and Ground. Use adapter cable for this. See ADAPTER CABLE, MODIFYING TO ACTIVATE POSITIONING MOTORS .

1. Remove glove compartment: See «GLOVE COMPARTMENT, REMOVING AND INSTALLING»(/audi/a4/b6-2000-2006/remont/mirrors/#interior-equipment-except-cabriolet__glove-compartment-removing-and-installing) (except Cabriolet). For the Cabriolet, see «GLOVE COMPARTMENT, ASSEMBLY OVERVIEW»(ref-197209-S32533520222005101300000) .
2. Disconnect connector -A-.
3. Unscrew bolts -B-.
4. Remove positioning motor.

Note. The curved washer on the positioning motor is color coded, the washer on Air Flow Flap Motor -V71- is light blue.

1. Place pin -A- into groove -C- and pin -B- in groove -D- of curved washer (pins -A- and -B- as well as grooves -C- and -D- have different sizes).

Note. When installing, ensure that actuator rods -E- and -F- sit on the correct pins.

Install all removed parts in reverse order, observe the following while doing so

1. Install the wiring harness so that it cannot come in contact with any moving parts (e.g. the actuating arm of the positioning motor).
2. Check DTC memory (see «DIAGNOSTIC TROUBLE CODE (DTC) MEMORY, CHECKING (FUNCTION 02)»(/audi/a4/b6-2000-2006/remont/communication-devices/#on-board-diagnostic-obd__diagnostic-trouble-code-dtc-memory-checking) ) and erase DTC memory (see «DIAGNOSTIC TROUBLE CODE (DTC) MEMORY, ERASING (FUNCTION 05)»(/audi/a4/b6-2000-2006/remont/communication-devices/#on-board-diagnostic-obd__diagnostic-trouble-code-dtc-memory-erasing) . Initiate basic setting (see «BASIC SETTING (FUNCTION 04)»(/audi/a4/b6-2000-2006/remont/communication-devices/#on-board-diagnostic-obd__basic-setting-function-04) .

Note. The function of the positioning motor can be checked for example: Connect both terminals "5" and "6" in positioning motor connector to 12V (DC), the motor moves in one direction until stop, the direction of rotation changes by reversing B+ and Ground. Use adapter cable for this. See ADAPTER CABLE, MODIFYING TO ACTIVATE POSITIONING MOTORS .

1. Remove glove compartment: See «GLOVE COMPARTMENT, REMOVING AND INSTALLING»(/audi/a4/b6-2000-2006/remont/mirrors/#interior-equipment-except-cabriolet__glove-compartment-removing-and-installing) (except Cabriolet). For the Cabriolet, see «GLOVE COMPARTMENT, ASSEMBLY OVERVIEW»(ref-197209-S32533520222005101300000) .
2. Reach between air conditioner and floor of plenum chamber on temperature sensor -A- and turn approx. 90°.
3. Pull temperature sensor -A- out of air conditioner.
4. Disconnect connector -B-. NOTE: If temperature sensor cannot be removed
5. Remove dust and pollen filter. See «DUST AND POLLEN FILTER ELEMENT, REMOVING AND INSTALLING»(/audi/a4/b6-2000-2006/remont/automatic-hvac-system/#air-conditioning__dust-and-pollen-filter-element-removing) .
6. Turn temperature sensor -A- in direction of arrow approx. 90° and remove from intake hole toward passenger compartment.

1. Check seating of O-ring seal -C- (if necessary lubricate using soap water)

Install all removed components in reverse order.

Scheme 6

Special tools and equipment

1. Hose clamps 3093 or 3094
2. Compressed air gun, standard
3. V.A.G 1274 hand pump with adapters

1. Remove plenum cover.
2. Disconnect battery and remove. NOTE: Obtain radio code before disconnecting battery. On vehicles with power seats, move the seats back as far as possible before disconnecting the battery.
3. Release pressure in coolant system by opening cap on coolant expansion tank.
4. Mark allocation of the coolant hoses -A- and -B-.
5. Clamp off and disconnect both coolant hoses leading to heater core in air conditioner unit (e.g. using V.A.G 3094)

Scheme 7

Note. The coolant hoses must be re-installed in the correct positions: - -Coolant hose -A- supply from cylinder head. - -Coolant hose -B- return to water pump. Bleed cooling circuit

See COOLING SYSTEM, DRAINING AND FILLING (1.8L Turbo), or COOLANT, DRAINING AND REFILLING (3.0L V6), or COOLING SYSTEM, DRAINING AND FILLING WITH COOLANT (4.2L V8).

1. Place container under connection -A-.
2. Place a piece of hose on connection -B- and carefully blow out coolant from heater core with compressed air.
3. Remove grommet -C-.
4. Remove driver side storage compartment. See «DRIVER-SIDE STORAGE COMPARTMENT (WITH AND WITHOUT KNEE BOLSTER), ASSEMBLY OVERVIEW»(/audi/a4/b6-2000-2006/remont/mirrors/#interior-equipment-except-cabriolet__driver-side-storage-compartment-with-and-without) (except Cabriolet). For the Cabriolet, see «DRIVER'S STORAGE COMPARTMENT (VEHICLES WITH AND WITHOUT KNEE BOLSTER), ASSEMBLY OVERVIEW»(ref-197209-S29048734852005101300000) .
5. Remove accelerator pedal module. See appropriate Fuel Supply article under FUEL SYSTEM.
6. Remove screws -A- and remove cover -B- from coolant lines.
7. Cover carpet beneath heater core connection with absorbent paper.
8. Loosen clamps -A- and pull out both coolant lines -B- and - C- from heater core connections.
9. Pull heater core -D- out of air conditioner.

Scheme 8

1. With the heater core removed, check air conditioner for soiling (via heater core opening).
2. If necessary remove dirt or coolant from air conditioner unit (for example after removing leaky heater core).
3. Check seals -A-, -B- and -C- on heater core, only install heater core with good seals.
4. Lubricate new seals -A- slightly with coolant.
5. Install new seals -A- (included in delivery) on the heater core connections -B
6. Push heater core -C- into the air conditioner unit.
7. Remove old clamps -A- from both coolant lines -B- and -C-.
8. Install new clamps -A- (included in delivery) on both coolant lines for heater core according to illustration.
9. Push both coolant lines -B- and -C- into heater core flange openings -D-.
10. Check seating of seals between coolant lines and heater core again.
11. Tighten both coolant lines -B- and -C- with clamps -A- on heater core.
12. Check seating of both clamps -A-, clamps must enclose the flange on heater core and coolant line completely and should not touch other components.
13. Tighten bolts on clamps -A- to 2.5 Nm.
14. Connect coolant hoses properly to heater core. Observe markings: A - supply hose from cylinder head B - return hose to water pump
15. Install removed components, except storage compartment driver's side, in reverse order.
16. Bleed coolant circuit: See «COOLING SYSTEM, DRAINING AND FILLING»(/audi/a4/b6-2000-2006/remont/cooling-fan/#engine-cooling-18l-4-cyl-5v-turbo-amb) (1.8L Turbo), or «COOLANT, DRAINING AND REFILLING»(/audi/a4/b6-2000-2006/remont/cooling-fan/#engine-cooling-30l-6-cylinder-5v-avk) (3.0L V6), or «COOLING SYSTEM, DRAINING AND FILLING WITH COOLANT»(ref-229838-S12242823052006042100000) (4.2L V8). NOTE: The heater core must additionally be bled due to the allocation of the coolant lines to the heater core. Use following procedure to bleed cooling system.
17. Bleed coolant circuit.
18. Switch ignition off.
19. Carefully open coolant reservoir cap (observe safety precautions when opening the cap) See «COOLING SYSTEM, DRAINING AND FILLING»(/audi/a4/b6-2000-2006/remont/cooling-fan/#engine-cooling-18l-4-cyl-5v-turbo-amb) (1.8L Turbo), or «COOLANT, DRAINING AND REFILLING»(/audi/a4/b6-2000-2006/remont/cooling-fan/#engine-cooling-30l-6-cylinder-5v-avk) (3.0L V6), or «COOLING SYSTEM, DRAINING AND FILLING WITH COOLANT»(ref-229838-S12242823052006042100000) (4.2L V8).
20. Loosen clamp on coolant hose -B-.
21. Pull hose -B- back until the hole in the coolant hose is no longer sealed with the pipe.
22. Increase pressure in coolant circuit e.g. using V.A.G1274 hand pump.
23. Bleed heater core via coolant hose -B- until coolant exits bubble free.
24. Push coolant hose -B- on heater core pipe and tighten with clamp.
25. Add coolant if necessary.
26. Check coolant circuit for leaks, pay particular attention between coolant hoses and heater core.
27. Install driver's side storage compartment and other removed components.

Air ducts in vehicle interior

Note. The ventilation of the passenger compartment occurs via two air extraction outlets (in luggage compartment right and left near the bumper), see AIR EXTRACTION VENT, CHECKING .

The following list pertains to see scheme 79.

1. Defroster outlet vent For front windshield Removing and installing: See «INTERIOR TRIM - EXCEPT CABRIOLET»(/audi/a4/b6-2000-2006/remont/gauges-instrument-panels/#interior-trim-except-cabriolet) or «INTERIOR TRIM - CABRIOLET»(/audi/a4/b6-2000-2006/remont/gauges-instrument-panels/#interior-trim-cabriolet) . If the Intermediate piece between air conditioner and air duct in the instrument panel has been pinched during installation, the air guide to the front windshield is uneven or insufficient.
2. Instrument panel Removing and installing: See «INSTRUMENT PANEL»(/audi/a4/b6-2000-2006/remont/gauges-instrument-panels/#interior-trim-except-cabriolet) (except Cabriolet), or «INSTRUMENT PANEL»(/audi/a4/b6-2000-2006/remont/gauges-instrument-panels/#interior-trim-cabriolet) for the Cabriolet. With air ducts to defroster vents and instrument panel vents driver and passenger side
3. Defroster outlet vent Side window/passenger side Removing and installing: See «INTERIOR TRIM - EXCEPT CABRIOLET»(/audi/a4/b6-2000-2006/remont/gauges-instrument-panels/#interior-trim-except-cabriolet) or «INTERIOR TRIM - CABRIOLET»(/audi/a4/b6-2000-2006/remont/gauges-instrument-panels/#interior-trim-cabriolet) .
4. Instrument panel vents Passenger-side Removing and installing: See «INTERIOR TRIM - EXCEPT CABRIOLET»(/audi/a4/b6-2000-2006/remont/gauges-instrument-panels/#interior-trim-except-cabriolet) , or «INTERIOR TRIM - CABRIOLET»(/audi/a4/b6-2000-2006/remont/gauges-instrument-panels/#interior-trim-cabriolet) .
5. Instrument panel vents Center Removing and installing: See «INTERIOR TRIM - EXCEPT CABRIOLET»(/audi/a4/b6-2000-2006/remont/gauges-instrument-panels/#interior-trim-except-cabriolet) , or «INTERIOR TRIM - CABRIOLET»(/audi/a4/b6-2000-2006/remont/gauges-instrument-panels/#interior-trim-cabriolet) .
6. Instrument panel vents Driver-side Removing and installing: See «INTERIOR TRIM - EXCEPT CABRIOLET»(/audi/a4/b6-2000-2006/remont/gauges-instrument-panels/#interior-trim-except-cabriolet) , or «INTERIOR TRIM - CABRIOLET»(/audi/a4/b6-2000-2006/remont/gauges-instrument-panels/#interior-trim-cabriolet) .
7. Defroster outlet vent Side window/driver side Removing and installing: See «INTERIOR TRIM - EXCEPT CABRIOLET»(/audi/a4/b6-2000-2006/remont/gauges-instrument-panels/#interior-trim-except-cabriolet) , or «INTERIOR TRIM - CABRIOLET»(/audi/a4/b6-2000-2006/remont/gauges-instrument-panels/#interior-trim-cabriolet) .
8. Intermediate piece/defroster channel Removing and installing, see «DEFROSTER VENT INTERMEDIATE PIECE FOR FRONT WINDSHIELD, REMOVING AND INSTALLING»(/audi/a4/b6-2000-2006/remont/automatic-hvac-system/#air-conditioning) .
9. Fresh air intake The air is sucked through the dust and pollen filter which is installed in the plenum chamber.
10. Recirculated air intake The air is sucked beneath the glove compartment from the passenger side footwell.
11. Air conditioner A/C unit, removing and installing, see «HEATING AND A/C UNIT, REMOVING AND INSTALLING»(/audi/a4/b6-2000-2006/remont/automatic-hvac-system/#air-conditioning)
12. Air duct /Instrument panel vents Center
13. Footwell vents front Driver and passenger side Removing and installing, see «FOOTWELL VENTS FRONT, REMOVING AND INSTALLING»(/audi/a4/b6-2000-2006/remont/automatic-hvac-system/#air-conditioning)
14. Intermediate piece to air duct rear footwell vent Driver-side
15. Intermediate piece to air duct rear footwell vent Passenger-side
16. Air duct footwell vents rear Driver-side
17. Air duct footwell vents rear Passenger-side
18. Trim with vent holes
19. Sealing plug Only on vehicles without glove compartment cooling.
20. Air duct for glove compartment Only on vehicles with glove compartment cooling.

Air distribution in air conditioner

Note. The cut away illustration of the air conditioner shows the flaps in the "Air guide to footwell" position and temperature position in "cooling" position (no air through heater core for heating)

The following list pertains to see scheme 80.

1. A - Driver side
2. B - Passenger's side
3. C - Air intake from passenger compartment air (recirculated air mode) Via passenger side footwell
4. D - Fresh air intake Via the dust and pollen filter which is installed in the plenum chamber
5. E - To front windshield vents (passenger side) The air from the center defroster vent comes from both sides of the air conditioner, the temperature depends on the mixture-ratio which has been selected by the temperature adjustment on the A/C control head -E87-.
6. E - To front windshield vents (drivers side) The air from the center defroster vent comes from both sides of the air conditioner, the temperature depends on the mixture-ratio which has been selected by the temperature adjustment on the A/C control head -E87-.
7. G - To instrument panel vents driver side
8. H - To footwell vents/driver side front
9. J - To instrument panel vents center The air from these vents comes from both sides of the air conditioner, the temperature depends on the mixture-ratio which has been selected by the temperature adjustment on the A/C control head -E87-.
10. K - To footwell vents - driver's side rear
11. L - To footwell vents - passenger's side rear
12. M - To footwell vents/passenger's side front
13. N - To instrument panel vents - passenger's side

The following list pertains to see scheme 80.

1. Fresh Air Blower -V2- With Control module for fresh air blower -J126
2. Recirculated air flap Marked in position "closed"
3. Fresh air flaps Marked in position "open" Both flaps are moved independently from each other by the curved washer and actuator lever attached on the positioning motor.
4. Defroster flap Marked in position "closed" Both flaps are moved together via lever and coupling elements that are attached on the outside of the air distribution housing.
5. Central flap 1 Marked in position "closed" Due to the shape of both outer flaps, with the center flap closed air can flow to the right and left vents. Both central flaps are moved independently from each other by the curved washer and actuator lever attached on the positioning motor.
6. Central flap 2 Marked in "open" position, air duct to footwell vents Both central flaps are moved independently from each other by the curved washer and actuator lever attached on the positioning motor.
7. Heater element for auxiliary heater -Z35- Only for vehicles with Diesel engine Not installed on USA vehicles
8. Heater core
9. Temperature flaps 2 One flap for driver's side and one for passenger side. Marked in position "cooling" The temperature flaps 2 are activated by temperature flaps 1 via coupling elements that are installed in the air distribution housing. See «COUPLING ELEMENT BETWEEN TEMPERATURE FLAPS "1" AND "2"»(/audi/a4/b6-2000-2006/remont/automatic-hvac-system/#air-conditioning__coupling-element-between-temperature-flaps-1) .
10. Temperature flaps 1 Marked in position "cooling" One flap for driver's side and one for passenger side.
11. Evaporator

Coupling element between temperature flaps "1" and "2"

The following list pertains to see scheme 81.

1. Coupling elements to positioning motor for left temperature flap (driver's side)
2. Temperature flap "1" driver's side
3. Coupling element driver's side
4. Temperature flap "2" driver's side
5. Coupling element passenger's side
6. Temperature flap "2" passenger's side
7. Temperature flap "1" passenger's side
8. Coupling elements to positioning motor for right temperature flap (passenger's side)

Note. With the heater core removed the coupling elements between both temperature flaps "1" and "2" are visible through the opening.

1. Remove instrument panel

See INSTRUMENT PANEL, REMOVING AND INSTALLING (except Cabriolet).

For the Cabriolet, see INSTRUMENT PANEL, REMOVING AND INSTALLING .

1. Loosen brake pedal mounting bracket (and clutch pedal) from central tube.
2. Loosen hex nuts -A- for central tube left side and unscrew approx. 15 mm.

See INTERIOR TRIM - EXCEPT CABRIOLET or INTERIOR TRIM - CABRIOLET .

1. Remove hex nuts -B- for central tube on right side.

See INTERIOR TRIM - EXCEPT CABRIOLET or INTERIOR TRIM - CABRIOLET .

Scheme 9

1. Remove connecting screws between central tube and the windshield cross member (in passenger compartment).
2. Remove connecting screws between central tube and the plenum chamber (between electronic box and windshield cross member in plenum chamber).

See INTERIOR TRIM - EXCEPT CABRIOLET .

For Cabriolet, see INTERIOR TRIM - CABRIOLET .

1. Pull central tube carefully back, until it touches the hex nuts on the left side and still rests on the threaded bolt on the right side.
2. Loosen intermediate piece -A- from central tube -B
3. Remove intermediate piece -A-.

Note. When installing the instrument panel, make sure that the intermediate piece for defrost fits properly on the defrost vent and that it is not pinched. After installing the instrument panel, check vent direction and air distribution of flowing air coming from the defrost vent to windshield.

1. Remove glove compartment and center console

See STORAGE COMPARTMENTS AND COVERS (except Cabriolet).

For the Cabriolet, see INTERIOR EQUIPMENT - CABRIOLET .

1. Remove brace -A- for central tube (passenger side on center tunnel)

See INTERIOR EQUIPMENT - EXCEPT CABRIOLET or INTERIOR EQUIPMENT - CABRIOLET .

Scheme 10

1. Remove screws -A- and -B- between brace -C- and the air conditioner.
2. Remove bracket -C- for central tube (driver's side on center tunnel).

Scheme 11

See INTERIOR EQUIPMENT - EXCEPT CABRIOLET or INTERIOR EQUIPMENT - CABRIOLET .

1. Remove the two intermediate pieces for the air duct footwell vents rear.

1. Mark connector -A- and -B- of -G261- and -G262- (mix-up alert)
2. Disconnect harness connectors -A- and -B- from footwell temperature sensors.
3. Remove screws -C-.
4. Loosen wiring harness from footwell vent -D-.
5. Pull footwell vent slightly back and remove toward passenger footwell.

Scheme 12

1. Place footwell vent with nose -A- first in opening of air conditioner -B-.
2. Install all components in reverse order.

1. VAS 5051 Vehicle Diagnostic, Testing and Information System (or V.A.G 1551 Scan Tool or V.A.G 1552 Scan Tool with V.A.G 1551/3 adapter cable) and if necessary V.A.G 6017 in case more vehicle systems are to be checked.
2. V.A.G 1362 tester (for temperature measurement)

Test requirements

1. The ambient temperature is greater than 15 °C.
2. Radiator and condenser are clean (clean if necessary)
3. The ribbed belt for compressor drive is OK and properly tightened. (not for vehicles with 8 cyl. engine)
4. All air ducts, covers and seals OK and properly installed (only for vehicles with 8 cyl. engine, see «VEHICLES WITH 8 CYL. ENGINE (COMPRESSOR DRIVE VIA A SHAFT)»(/audi/a4/b6-2000-2006/remont/automatic-hvac-system/#air-conditioning__vehicles-with-8-cyl-engine-compressor) ).
5. Air flow through dust and pollen filter not obstructed by dirt.
6. Vehicle not standing in direct sunlight.
7. Engine at normal operating temperature
8. DTC memory checked (see «DIAGNOSTIC TROUBLE CODE (DTC) MEMORY, CHECKING (FUNCTION 02)»(/audi/a4/b6-2000-2006/remont/communication-devices/#on-board-diagnostic-obd__diagnostic-trouble-code-dtc-memory-checking) . All displayed malfunctions eliminated and DTC memory was erased (see «DIAGNOSTIC TROUBLE CODE (DTC) MEMORY, ERASING (FUNCTION 05)»(/audi/a4/b6-2000-2006/remont/communication-devices/#on-board-diagnostic-obd__diagnostic-trouble-code-dtc-memory-erasing) .
9. The coding was checked and if necessary corrected. See «A/C CONTROL HEAD -E87-, CODING (FUNCTION 07)»(/audi/a4/b6-2000-2006/remont/communication-devices/#on-board-diagnostic-obd__ac-control-head-e87-coding-function) and «READ MEASURING VALUE BLOCK (FUNCTION 08)»(/audi/a4/b6-2000-2006/remont/communication-devices/#on-board-diagnostic-obd__read-measuring-value-block-function-08) .
10. The basic setting was carried out. See «BASIC SETTING (FUNCTION 04)»(/audi/a4/b6-2000-2006/remont/communication-devices/#on-board-diagnostic-obd__basic-setting-function-04) .
11. All instrument panel vents open.
12. The hood is closed.
13. Settings on A/C Control Head -E87

AUTO mode

Temperature selection LO (for both driver's and passenger's side)

Compressor on (indicator light in "Econ" button does not come on).

1. Functions with engine running: - - Coolant Fan -V7- is running (speed depends on pressure in refrigerant circuit and engine temperature). - - Fresh Air Blower -V2- runs at maximum speed. - - The air conditioner goes in recirculated air mode (approx. 1 minute after starting the vehicle the fresh/back pressure flaps will be closed and the recirculated air flap will open, the Fresh Air Blower -V2- sucks the air from the passenger footwell).

Note. Check DTC memory if a test requirement is not obtained (see DIAGNOSTIC TROUBLE CODE (DTC) MEMORY, CHECKING (FUNCTION 02) . Carry out an output Diagnostic Test Mode (DTM) (see OUTPUT DIAGNOSTIC TEST MODE (DTM) (FUNCTION 03) .

Checking

1. Measure ambient temperature (must greater than 15 °C).
2. Close doors, hood, window and sunroof.
3. Open all dash panel vents.
4. Switch ignition on.
5. Select ECON mode on A/C control head -E87- (indicator light in ECON button lights up).
6. Start engine.
7. Initiate On Board Diagnostic (OBD) of air conditioner. See «VAS 5051 VEHICLE DIAGNOSTIC, TESTING AND INFORMATION SYSTEM, CONNECTING AND SELECTING FUNCTIONS»(/audi/a4/b6-2000-2006/remont/communication-devices/#on-board-diagnostic-obd) .
8. Select «READ MEASURING VALUE BLOCK (FUNCTION 08)»(/audi/a4/b6-2000-2006/remont/communication-devices/#on-board-diagnostic-obd__read-measuring-value-block-function-08) , «DISPLAY GROUP 001»(/audi/a4/b6-2000-2006/remont/communication-devices/#on-board-diagnostic-obd) .
9. Check indication in display fields
10. Display field "2" shows 0% (compressor is switched off)
11. Display field "4" shows, that the pressure in the refrigerant circuit measured at ambient temperature is the same or greater as the table value.

INDICATION IN DISPLAY FIELD 4

Note. At absolute pressure, 0 bar corresponds to absolute vacuum. Normal ambient pressure corresponds to approximately 1 bar absolute pressure. 0 pressure corresponds to an absolute pressure of one bar on most pressure gauges (indicated by -1 below 0). The pressure in the refrigerant circuit depends on the ambient temperature. Via heat emission of components (e.g. coolant fan), with the engine at operating temperature a slightly higher pressure is displayed as for the respective ambient temperature.

1. If the displayed pressure is lower than in the table: - - Check measuring value of High Pressure Sensor - G65-. See «READ MEASURING VALUE BLOCK (FUNCTION 08)»(/audi/a4/b6-2000-2006/remont/communication-devices/#on-board-diagnostic-obd__read-measuring-value-block-function-08) and «TEST STEPS 5 TO 9»(/audi/a4/b6-2000-2006/remont/communication-devices/#on-board-diagnostic-obd) "electrical testing, test step 5". - - If no malfunction can be detected on high pressure sensor, there is not enough refrigerant in the circuit.

If the pressure in the refrigerant circuit is OK.

1. Switch compressor on, for this select "Auto" mode on A/C control head -E87- (indicator light in "ECON" button does not light up).
2. Select temperature mode "Lo" (for driver's and passenger's side) on A/C Control Head -E87-.
3. Select air flow direction on A/C Control Head -E87- to "air from dash panel vents"
4. Select «READ MEASURING VALUE BLOCK (FUNCTION 08)»(/audi/a4/b6-2000-2006/remont/communication-devices/#on-board-diagnostic-obd__read-measuring-value-block-function-08) , «DISPLAY GROUP 001»(/audi/a4/b6-2000-2006/remont/communication-devices/#on-board-diagnostic-obd) .
5. Check indication in display fields: - Display field "2" shows a duty cycle greater than 30% (A/C Compressor Regulator Valve -N280- is activated, compressor is switched on) - Display field "1" shows a current greater than 0.3 A (current flows via A/C Compressor Regulator Valve -N280-, compressor is switched on) - The shown pressure in display field "4" rises above the value with the compressor switched on.

Note. A/C Compressor Regulator Valve -N280- is activated by A/C Control Head -E87- so that the air temperature after evaporator reaches the specified value (approx. 2 to 5 °C). A value 75% (0.55 A) greater is displayed after engine start depending on the measured temperature, engine speed and voltage supply. As soon as the measured temperature from Evaporator Vent Temperature Sensor -G263- approaches the specified value, the activation is reduced and the compressor performance is decreased. Under certain operating conditions, residual moisture in refrigerant circuit can lead to an ice build-up at the compressor regulator valve. Compressor control is reduced by this ice build-up, evaporator is cooled too intensely and freezes. The freeze-up of the evaporator can be the cause for the following customer complaints

1. After a long drive, A/C system repeatedly or sporadically fails (no cooling or heating performance), after switching off vehicle and after a short time, A/C function is OK again.
2. After a long drive, windows fog up from inside, windows are also not cleared by pressing the "Defrost" button, after switching off vehicle and after a short time, A/C function is OK again.

Repair steps

Scheme 13

1. Check measured value of Evaporator Vent Temperature Sensor -G263-. See «READ MEASURING VALUE BLOCK (FUNCTION 08)»(/audi/a4/b6-2000-2006/remont/communication-devices/#on-board-diagnostic-obd__read-measuring-value-block-function-08) , «DISPLAY GROUP 010»(/audi/a4/b6-2000-2006/remont/communication-devices/#on-board-diagnostic-obd__display-group-010) . If measured value of the sensor is too low under operating conditions specified by Service (at an ambient temperature above 0° C, colder than 0° C for a long period of time although A/C Compressor Regulator Valve -N280- is not activated at the time), perform the following work steps (discharge refrigerant circuit, replace accumulator and then evacuate refrigerant circuit for a minimum of 3 hours).
2. Check refrigerant line from evaporator to accumulator (thick tube, low pressure side) with engine running. If this line is thickly iced-up when complaint occurs (a very thin layer of ice is permitted), this indicates that the temperature in evaporator is too low.
3. If the measuring value of the sensor is too high for the operating requirements described by the customer (higher than e.g. 10° C even though the A/C system is functioning properly) check Evaporator Vent Temperature Sensor - G263- (the condenser can ice over due to an incorrect measuring value).
4. If the measuring value of the sensor is too low for the operating requirements described by the customer (at an ambient temperature above 0° C, it is colder than 0° C for an extended period of time even though A/C Compressor Regulator Valve -N280- is not currently being activated) Take vehicle to a dealership which services A/C systems. - - Check refrigerant line from condenser to accumulator (thick line, low-pressure side) with the engine running. If this line is strongly iced over when the complaint condition occurs (a thin layer of ice is permissible) this also indicates that the temperature in condenser is too low. - - If necessary, make the climate control supporting workshop aware of the determined deficiency if necessary, the required work can only be performed there (empty refrigerant circuit, replace accumulator and then evacuate refrigerant circuit for at least 3 hours). If display field "1" shows no or not enough current, check activation of A/C Compressor Regulator Valve. See «TEST STEPS 5 TO 9»(/audi/a4/b6-2000-2006/remont/communication-devices/#on-board-diagnostic-obd) "Electrical testing test step 6". If the shown pressure in display field "4" does not change and the activation of the compressor is OK (display field "1" and "2"), the refrigerant circuit has a malfunction. - Press button for "air recirculation" (symbol for "air recirculation" mode button is lit up). - Increase engine speed to 2000 RPM (timed period begins). - Select «READ MEASURING VALUE BLOCK (FUNCTION 08)»(/audi/a4/b6-2000-2006/remont/communication-devices/#on-board-diagnostic-obd__read-measuring-value-block-function-08) , «DISPLAY GROUP 010»(/audi/a4/b6-2000-2006/remont/communication-devices/#on-board-diagnostic-obd__display-group-010) . - Compare displayed measuring value (of Evaporator Vent Temperature Sensor -G263-) in display field "1" with values in diagram. A - Measured air temperature of Evaporator Vent Temperature Sensor -G263- B - Ambient temperature C - Permissible tolerance Depending on the ambient temperature, the measured air temperature should be after 5 minutes within the shown tolerance range. NOTE: If the required values are not obtained, check the measuring value of Evaporator Vent Temperature Sensor - G263-, compare shown measuring values in display group "010" display field "1" and display group "009" display fields "3" and "4" with each other. - If the measuring value in both display fields "3" or "4" deviates only slightly from the measuring value in display group "010", Carry out "Identifying malfunctions if specified values are not obtained". See «IDENTIFYING MALFUNCTIONS IF SPECIFIED VALUES ARE NOT OBTAINED»(/audi/a4/b6-2000-2006/remont/automatic-hvac-system/#air-conditioning__identifying-malfunctions-if-specified-values-are) . - If the measuring value of Evaporator Vent Temperature Sensor -G263- is greater than Left Vent Temperature Sensor -G150- and Right Vent Temperature Sensor -G151-, check - G263- for correct installation and carry out electrical testing for this sensor. See «TEST STEP 2»(/audi/a4/b6-2000-2006/remont/communication-devices/#on-board-diagnostic-obd) . The function of the air conditioning is recognizable, e.g. the refrigerant pipe on the low pressure side (big line) cools off. If the measuring value of Evaporator Vent Temperature Sensor -G263- is OK (and therefore the cooling performance of the air conditioning system). - Compare the measuring value (of Evaporator Vent Temperature Sensor -G263-) in display group "010" display field 1 with the measuring values of display group "009" display fields "3" and "4" (-G150- and -G151-). After 5 minutes, the measuring values in display group "009" display field "3" and "4" (-G150- and -G151-) can be maximum 3° C greater than the value in display field "1" of display group "010" (of Evaporator Vent Temperature Sensor -G263-). NOTE: If the required values are not obtained, compare displayed measuring values in display group "009" display fields "3" and "4" with each other: - If the measuring value in one the two display fields "3" or "4" is OK. Check positioning motor for temperature flap on the side where the measuring value is not OK (Actuator for temperature flap left -V158- or Actuator for temperature flap right -V159-). See «TEST STEP 2»(/audi/a4/b6-2000-2006/remont/communication-devices/#on-board-diagnostic-obd) . - If the measuring value in display group "009" display fields "3" or "4" is lower than the measuring value in display group "010" display field "1", check Evaporator Vent Temperature Sensor -G263-, Left Vent Temperature Sensor -G150- and Right Vent Temperature Sensor -G151- for correct installation and their electrical connections for contact resistance, if necessary replace faulty sensor. - If no malfunction is detected on -G150- and -G151-, as well as on -V158- and -V159-, carry out «IDENTIFYING MALFUNCTIONS AT TEMPERATURE INCREASE BEHIND CONDENSER»(/audi/a4/b6-2000-2006/remont/automatic-hvac-system/#air-conditioning__identifying-malfunctions-at-temperature-increase-behind) . The air temperature of the center dash panel vents can be measured e.g. using the V.A.G 1362 mini tester. The measuring values of Left Footwell Vent Temperature Sensor -G261- and Right Footwell Vent Temperature Sensor -G262- are shown in display group "009", display fields "1" and "2". The two sensors show an incorrect value, because in "AUTO" mode most of the air flow is directed to the dash panel vents. By pressing the "Air to footwell" button, these sensors can also be checked in this test.

Identifying malfunctions if specified values are not obtained

1. Select «READ MEASURING VALUE BLOCK (FUNCTION 08)»(/audi/a4/b6-2000-2006/remont/communication-devices/#on-board-diagnostic-obd__read-measuring-value-block-function-08) , «DISPLAY GROUP 001»(/audi/a4/b6-2000-2006/remont/communication-devices/#on-board-diagnostic-obd) .
2. Repeat A/C system cooling performance test. See «A/C REFRIGERANT SYSTEM COOLING PERFORMANCE, TESTING»(/audi/a4/b6-2000-2006/remont/automatic-hvac-system/#air-conditioning) .
3. Observe during the cooling performance test display field "1" and "4". Was the activation of A/C Compressor Regulator Valve -N280- during the cooling performance test switched off (control current was less than 0.55 A)? If Yes: Go to «CHECK DTC MEMORY AND READ MEASURING VALUE BLOCK»(/audi/a4/b6-2000-2006/remont/automatic-hvac-system/#air-conditioning__check-dtc-memory-and-read-measuring) . If No: Go to «DID THE PRESSURE IN REFRIGERANT CIRCUIT (DISPLAY FIELD "4") INCREASE DURING COOLING PERFORMANCE TEST?»(/audi/a4/b6-2000-2006/remont/automatic-hvac-system/#air-conditioning__did-the-pressure-in-refrigerant-circuit) .

Check DTC memory and read measuring value block

1. Check DTC memory (see «DIAGNOSTIC TROUBLE CODE (DTC) MEMORY, CHECKING (FUNCTION 02)»(/audi/a4/b6-2000-2006/remont/communication-devices/#on-board-diagnostic-obd__diagnostic-trouble-code-dtc-memory-checking) ), eliminate displayed malfunctions, and erase DTC memory (see «DIAGNOSTIC TROUBLE CODE (DTC) MEMORY, ERASING (FUNCTION 05)»(/audi/a4/b6-2000-2006/remont/communication-devices/#on-board-diagnostic-obd__diagnostic-trouble-code-dtc-memory-erasing) .
2. «READ MEASURING VALUE BLOCK (FUNCTION 08)»(/audi/a4/b6-2000-2006/remont/communication-devices/#on-board-diagnostic-obd__read-measuring-value-block-function-08) , «DISPLAY GROUP 002»(/audi/a4/b6-2000-2006/remont/communication-devices/#on-board-diagnostic-obd) (compressor cut-off conditions), and eliminate cause for cut-off. See «INTERPRETATION OF COMPRESSOR CUT-OFF CONDITION FOR DISPLAY FIELD 1 - 4»(/audi/a4/b6-2000-2006/remont/communication-devices/#on-board-diagnostic-obd__interpretation-of-compressor-cut-off-condition-for) . - Repeat cooling performance test.

Did the pressure in refrigerant circuit (display field "4") increase during cooling performance test?

1. Yes: Go to «CONTINUATION OF TEST - PRESSURE IN REFRIGERANT CIRCUIT INCREASES»(/audi/a4/b6-2000-2006/remont/automatic-hvac-system/#air-conditioning__continuation-of-test-pressure-in) .
2. Continuation (next page)
3. No: - Malfunction in refrigerant circuit. See «A/C REFRIGERANT SYSTEM, TESTING»(/audi/a4/b6-2000-2006/remont/automatic-hvac-system/#air-conditioning) .

Continuation of test - Pressure in refrigerant circuit increases

1. Open hood.
2. Repeat A/C system cooling performance test. See «A/C REFRIGERANT SYSTEM COOLING PERFORMANCE, TESTING»(/audi/a4/b6-2000-2006/remont/automatic-hvac-system/#air-conditioning) .

1. Does the Coolant Fan -V7- run during cooling performance test (speed depends on coolant temperature and pressure in refrigerant circuit, speed is determined by Engine Control Module (ECM))?

1. Yes: Go to «READ MEASURING VALUE BLOCK (FUNCTION 08), DISPLAY FIELD "4"»(/audi/a4/b6-2000-2006/remont/automatic-hvac-system/#air-conditioning__read-measuring-value-block-function-08)

1. No: Go to «CHECK ACTIVATION OF COOLANT FAN -V7»(/audi/a4/b6-2000-2006/remont/automatic-hvac-system/#air-conditioning__check-activation-of-coolant-fan-v7)

READ MEASURING VALUE BLOCK (FUNCTION 08), display field "4"

1. See «READ MEASURING VALUE BLOCK (FUNCTION 08)»(/audi/a4/b6-2000-2006/remont/communication-devices/#on-board-diagnostic-obd__read-measuring-value-block-function-08) , «DISPLAY GROUP 001»(/audi/a4/b6-2000-2006/remont/communication-devices/#on-board-diagnostic-obd) , display field "4" (pressure in refrigerant circuit).

1. If the Coolant Fan -V7- runs at higher speed when pressures increases in refrigerant circuit. See «READ MEASURING VALUE BLOCK (FUNCTION 08)»(/audi/a4/b6-2000-2006/remont/communication-devices/#on-board-diagnostic-obd__read-measuring-value-block-function-08) , «DISPLAY GROUP 014»(/audi/a4/b6-2000-2006/remont/communication-devices/#on-board-diagnostic-obd__display-group-014) .

1. If Yes: - Malfunction in refrigerant circuit. See «A/C REFRIGERANT SYSTEM, TESTING»(/audi/a4/b6-2000-2006/remont/automatic-hvac-system/#air-conditioning) .

Check activation of Coolant Fan -V7

1. Check activation of Coolant Fan -V7-. Carry out «OUTPUT DIAGNOSTIC TEST MODE (DTM) (FUNCTION 03)»(/audi/a4/b6-2000-2006/remont/communication-devices/#on-board-diagnostic-obd__output-diagnostic-test-mode-dtm-function) .
2. Repair activation of Coolant Fan -V7-.
3. Repeat A/C system cooling performance test. See «A/C REFRIGERANT SYSTEM COOLING PERFORMANCE, TESTING»(/audi/a4/b6-2000-2006/remont/automatic-hvac-system/#air-conditioning) .

1. No: Go to next step.

1. Check activation of Coolant Fan -V7-. Carry out «OUTPUT DIAGNOSTIC TEST MODE (DTM) (FUNCTION 03)»(/audi/a4/b6-2000-2006/remont/communication-devices/#on-board-diagnostic-obd__output-diagnostic-test-mode-dtm-function) .
2. Repair activation of Coolant Fan -V7-.

1. The pressure in the refrigerant circuit depends on various factors. However, at an ambient temperature between 20 to 25° C the pressure should not exceed more than 20 bar. Due to high coolant performance, pressures up to 31 bar may occur under extreme operating conditions (e.g. in southern countries with high ambient temperatures, "stop and go" traffic and high humidity).
2. The pressure in the refrigerant system does not increase above 16 bar at ambient temperatures lower than 25° C (the coolant fan runs and cools the condenser).
3. Via the duty cycle ( «READ MEASURING VALUE BLOCK (FUNCTION 08)»(/audi/a4/b6-2000-2006/remont/communication-devices/#on-board-diagnostic-obd__read-measuring-value-block-function-08) , «DISPLAY GROUP 001»(/audi/a4/b6-2000-2006/remont/communication-devices/#on-board-diagnostic-obd) , display field "3") the A/C Control Head -E87- calculates the pressure in the refrigerant circuit.
4. When the duty cycle is smaller than 12.5% (corresponds to approx.: 1.8 bar absolute pressure) and greater than 87.5% (corresponds to approx.: 32 bar absolute pressure) the compressor is not switched on by the A/C Control Head -E87- (A/C Compressor Regulator Valve -N280- is not activated). The compressor will be switched on again when duty cycle is greater than 12.5% (correspond 1.8 bar absolute pressure) or smaller than 48% (corresponds to 16 bar absolute pressure).
5. If the pressure in the refrigerant circuit or the engine coolant temperature is too high, the A/C Control Head -E87- regulates the compressor performance (to avoid sudden compressor cut-off)

1. When pressure in refrigerant circuit exceeds 30 bar (absolute pressure) (the complete compressor output is only switched again after the pressure is less than 27 bar).
2. As soon as the coolant temperature reaches 115° C (at 118° C compressor is switched off completely).

1. If the pressure in the refrigerant circuit was greater than 32 bar (duty cycle greater than 87.5%) the compressor is switched on again by the A/C control head -E87-, if pressure drops below 29 bar (duty cycle is less than 84%).
2. Additional notes on pressures in the refrigerant circuit, see «READ MEASURING VALUE BLOCK (FUNCTION 08)»(/audi/a4/b6-2000-2006/remont/communication-devices/#on-board-diagnostic-obd__read-measuring-value-block-function-08) , «DISPLAY GROUP 001»(/audi/a4/b6-2000-2006/remont/communication-devices/#on-board-diagnostic-obd) .

Identifying malfunctions at temperature increase behind condenser

1. Pinch both coolant hoses from engine to heater core using hose clamps 3093 or 3094.
2. Repeat A/C system cooling performance test, see «A/C REFRIGERANT SYSTEM COOLING PERFORMANCE, TESTING»(/audi/a4/b6-2000-2006/remont/automatic-hvac-system/#air-conditioning) . Do both measuring values in display fields "3" and "4" of display group "009" deviate less than 3° C from Evaporator Vent Temperature Sensor -G263- (display field "1" of display group "010"?

1. Yes: Go to «CHECK ACTIVATION OF ACTUATOR FOR TEMPERATURE FLAP LEFT - V158»(/audi/a4/b6-2000-2006/remont/automatic-hvac-system/#air-conditioning__check-activation-of-actuator-for-temperature)

1. No: Go to «CHECK SENSOR»(/audi/a4/b6-2000-2006/remont/automatic-hvac-system/#air-conditioning__check-sensor)

Check activation of Actuator for temperature flap left - V158

1. Remove both hose clamps 3093 or 3094 from coolant hoses.
2. Check activation of Actuator for temperature flap left - V158- and Actuator for temperature flap right -V159-, carry out output Diagnostic Test Mode. See «OUTPUT DIAGNOSTIC TEST MODE (DTM) (FUNCTION 03)»(/audi/a4/b6-2000-2006/remont/communication-devices/#on-board-diagnostic-obd__output-diagnostic-test-mode-dtm-function) .
3. Check position of temperature flaps and actuator levers of Actuator for temperature flap left -V158- and Actuator for temperature flap right -V159-. See «ACTUATOR FOR TEMPERATURE FLAP LEFT -V158-, REMOVING AND INSTALLING»(/audi/a4/b6-2000-2006/remont/automatic-hvac-system/#air-conditioning__actuator-for-temperature-flap-left-v158) and «ACTUATOR FOR TEMPERATURE FLAP RIGHT -V159-, REMOVING AND INSTALLING»(/audi/a4/b6-2000-2006/remont/automatic-hvac-system/#air-conditioning__actuator-for-temperature-flap-right-v159) .

Check sensor

1. Check sensor which measuring value deviates for correct installation and electrical connection for contact resistance.
2. Eliminate malfunction cause for incorrect measuring value, if necessary replace faulty sensor.

A/C refrigerant system, leak testing

1. Use halogen leak detector Hitec HI400A-TEL or equivalent to check for refrigerant leaks.
2. Refrigerant gas dissipates very quickly. Avoid drafty or windy areas when checking for leaks.
3. Some refrigerant leaks are apparent by refrigerant oil deposits on or near leak location. Confirm by using leak detector.
4. If the refrigerant system is discharged (empty), charge system with approx. 100 g (3.5 oz) of refrigerant in order to check for leaks. See «A/C REFRIGERANT SYSTEM (R-134A), EVACUATING AND RECHARGING»(/audi/a4/b6-2000-2006/remont/automatic-hvac-system/#air-conditioning__ac-refrigerant-system-r-134a-evacuating-and) .

1. Check refrigerant system for leaks following leak detector manufacturer's instructions.
2. Check for refrigerant leaks by passing detector probe under suspected leaking components.

Note. Refer to leak detector manufacturer's instructions.

A/C refrigerant system, testing with pressure gauges

Due to the constant temperature/pressure relationship of R-134a, approximate high side system temperature can be determined based on system pressure.

Pressure gauges may have one or more temperature scales in addition to the pressure scale. Since various refrigerants have different temperature/pressure relationships, each gauge is specific for a particular refrigerant.

Measuring pressure and temperature in a "switched-on" refrigerant system

Use the A/C refrigerant high pressure gauge to measure the high side system pressure between the compressor and restrictor (including condenser) with the A/C switched on.

The temperature display of the high pressure gauge applies only to a portion of the high pressure side. The high pressure gauge displays approximate temperature between the compressor outlet and restrictor.

Note. The temperature/pressure relationship only holds true when the refrigerant system contains liquid and vapor, but not when it contains only gas. In the gaseous state, the temperature is approx. 10-30° C (18-54° F) higher than indicated on the pressure gauge.

Measuring pressure and temperature in a closed container or "switched-off" refrigerant system

Due to the constant temperature/pressure relationship of R-134a, approximate temperature of refrigerant in a closed container or in a switched-off A/C system can be determined based on its pressure.

If the temperature displayed on the gauge is lower than the actual temperature of the refrigerant, the refrigerant container or system is empty (discharged).

Note. The temperature/pressure relationship only holds true when the refrigerant system contains liquid and vapor, but not when it contains only gas. In the gaseous state, the temperature is approx. 10-30° C (18-54° F) higher than indicated on the pressure gauge.

A/C refrigerant system, checking pressures

Safety measures, see SAFETY PRECAUTIONS .

Before checking refrigerant system pressures, check A/C system cooling performance. See A/C REFRIGERANT SYSTEM COOLING PERFORMANCE, TESTING .

Use high pressure service valve for checking system pressures.

1. Condenser and radiator clean and free of obstructions (clean if necessary)
2. Drive belts for compressor and generator in good condition and properly tensioned
3. All air ducts, covers and seals OK and correctly installed
4. Check DTC memory using V.A.G 1551 scan tool and eliminate/repair any malfunctions indicated (not affecting A/C system)
5. All air distribution flaps reach end positions
6. Engine at normal operating temperature
7. Evaporator housing and heater box do not leak air (draw in secondary air) at high fresh air blower speed
8. Outside (ambient) temperature must be between 15-45° C (59-113° F)
9. Engine running and system set to maximum cooling (AUTO operating mode with LO temperature setting selected)

1. Switch compressor on (warning light in ECON button does not light up)
2. Temperature selection LO (for driver and passenger side)

If the compressor is activated (A/C compressor is switched on)

1. Fresh air blower -V2- runs
2. Coolant fan -V7- runs (at least in 1st speed)
3. Air flow flap closes and fresh air/recirculated air flap opens (within 1 minute after starting vehicle)

Note. With fresh air/recirculated air flap open air flows out of outlets in the instrument panel even though the air flow flap is closed.

Preparation work

1. Check DTC memory and determine and repair all possible malfunctions. See «DIAGNOSTIC TROUBLE CODE (DTC) MEMORY, CHECKING (FUNCTION 02)»(/audi/a4/b6-2000-2006/remont/communication-devices/#on-board-diagnostic-obd__diagnostic-trouble-code-dtc-memory-checking) .

1. Switch ignition off.
2. Connect high pressure hose of refrigerant recovery/recycling/recharging unit Kent-Moore ACR 4 , or equivalent, to high pressure service connection. See «DISCHARGING»(/audi/a4/b6-2000-2006/remont/automatic-hvac-system/#air-conditioning__discharging) .
3. Leave low pressure hose of refrigerant recovery/recycling/recharging unit disconnected.

Note. Only the high pressure service valve is used for A/C system servicing. Perform all A/C system service operations (i.e. discharging, evacuating and charging) through the high pressure service valve only.

OUTSIDE TEMPERATURE VERSUS A/C REFRIGERANT PRESSURES

If A/C refrigerant system base pressure is less than specified on chart, system is low on refrigerant

1. Check system for leaks using halogen leak detector Hitec HI400A-TEL or equivalent, repair system as necessary.
2. Check pressure relief valve on A/C compressor.

If the pressure relief valve has blown

1. Check actuation of coolant fan -V7- according to wiring diagram.
2. Check for pinched, kinked or damaged refrigerant lines/hoses.

If no problems are found

1. Discharge refrigerant system (see «A/C REFRIGERANT SYSTEM (R-134A), DISCHARGING»(/audi/a4/b6-2000-2006/remont/automatic-hvac-system/#air-conditioning__ac-refrigerant-system-r-134a-discharging) ), then evacuate and recharge (see «A/C REFRIGERANT SYSTEM (R-134A), EVACUATING AND RECHARGING»(/audi/a4/b6-2000-2006/remont/automatic-hvac-system/#air-conditioning__ac-refrigerant-system-r-134a-evacuating-and) ).

If A/C refrigerant system pressure corresponds to or is higher than base pressure specified on chart

1. Start engine.
2. Adjust A/C to maximum cooling.

Compressor runs continuously.

1. Raise engine speed to 2000 RPM.
2. Note pressure on A/C high pressure gauge.

Specified high pressure value: high side (discharge) pressure increases from base pressure (engine OFF) to maximum 20 bar (290 psi).

Pressure in A/C system corresponds to chart or is higher

1. Start engine.
2. Adjust A/C to maximum cooling performance.

Note. If compressor is not activated, note test requirements.

A/C refrigerant system (R-134a), discharging

Note. Follow all safety measures starting on SAFETY PRECAUTIONS when discharging the A/C refrigerant system.

Discharging

Make sure initial set-up has been performed on recovery/recycling/recharging unit before discharging A/C system.

1. Connect red high pressure hose -A- of refrigerant recovery/recycling/recharging unit to high pressure service valve (fitting) on vehicle and open coupler valve.
2. Leave blue low pressure hose -B- of refrigerant recovery/recycling/recharging unit disconnected.

Note. Only the high pressure service valve is used for A/C system servicing. Perform all A/C system service operations (i.e. discharging, evacuating and charging) through the high pressure service valve only.

1. Following refrigerant recovery/recycling/recharging unit manufacturer's instructions, discharge A/C system into refrigerant recovery/recycling/recharging unit.

A/C refrigerant system (R-134a), evacuating and recharging

Note. Only the high pressure service valve is used for A/C system servicing. Perform all A/C system service operations (i.e. discharging, evacuating and recharging) through the high pressure service valve only.

Evacuating and recharging

Follow all safety measures starting on SAFETY PRECAUTIONS , when evacuating and recharging the A/C refrigerant system.

1. Follow refrigerant recovery/recycling/recharging unit manufacturer's instructions for evacuating and recharging A/C system.
2. Evacuate refrigerant system for a minimum of 30 minutes.
3. When recharging A/C system, add correct amount of refrigerant and PAG oil to system. See «REFRIGERANT (PAG) OIL, SYSTEM CAPACITY»(/audi/a4/b6-2000-2006/remont/automatic-hvac-system/#air-conditioning__refrigerant-pag-oil-system-capacity) .
4. After system recharge, manually rotate A/C compressor approx. 10 turns before starting engine. Start engine with A/C OFF. After idle speed has stabilized, switch A/C ON and let engine idle (compressor running) for minimum of two minutes before raising engine speed.

A/C refrigerant system (R-134a), flushing with compressed air and nitrogen

1. Use compressed air and nitrogen (available locally) to remove moisture, impurities and old refrigerant oil from A/C refrigerant system.
2. First blow out old refrigerant oil and dirt with compressed air, then dry components with nitrogen.
3. DO NOT blow compressed air and nitrogen through the compressor or restrictor.
4. Always flush components in opposite direction of refrigerant flow.
5. Flush evaporator through the low pressure line with the high pressure line removed.
6. Blow through the refrigerant line from accumulator to compressor in flow direction of refrigerant (there is no thread on connection to compressor).
7. If any component has dark thick deposits that cannot be removed with compressed air, replace component.
8. Thin light gray deposits in refrigerant lines and hoses are normal and do not impair the function of the system.
9. Always replace accumulator and restrictor after flushing.

Flush refrigerant system with compressed air and nitrogen if

1. Refrigerant oil is dark and viscous (thick).
2. Too much refrigerant oil is in the system following compressor replacement.
3. It is unclear or not known how much refrigerant oil is in system.
4. Moisture, dirt or other impurities have entered the refrigerant system (e.g. following an accident).
5. System is unable to pull a constant vacuum during evacuation of a leak-free system due to excessive moisture in the system.
6. Refrigerant system has been open longer than the time required for normal repairs (i.e. following an accident).
7. Based on temperature and pressure measurements, the system is diagnosed with moisture contamination.
8. Compressor is replaced due to noises or internal damage.
9. Flushing is required after replacing certain components in certain situations. See «A/C SYSTEM, REPLACING COMPONENTS»(/audi/a4/b6-2000-2006/remont/automatic-hvac-system/#air-conditioning__ac-system-replacing-components) .

A/C refrigerant system, servicing

Note. For the different work procedures, refer to the repair manual "A/C system with refrigerant R134a", this can be found (e.g. for rest of world) in "ELSA" under "Internet" (the globe), "Audi" (the flag with your language), "Technical Information" (arrow). No refrigerant must be added into the refrigerant circuit (discharge, evacuate and recharge refrigerant circuit). With the engine running the compressor is always driven, the compressor has no A/C clutch. For this reason, the engine should only be started when the refrigerant circuit is completely and properly installed. For example; if the refrigerant lines are not connected, when the engine is running the compressor may heat up (via internal heat generation) until compressor damage occurs. The reason for internal heat generation is, the compressor operates with almost 0% pump capacity against permanent resistance (locked circuit). To avoid compressor damage in the event the refrigerant circuit is empty, the compressor is designed is such way, the compressor is regulated to approx. 0% capacity and is lubricated with the remaining oil in compressor via an internal oil circuit. The replacement-compressor contains the oil capacity for the entire refrigerant circuit: see Refrigerant sticker located in engine compartment or A/C REFRIGERANT SYSTEM, CAPACITIES . Zexel, Sanden and Denso compressors require different refrigerant oils: see REFRIGERANT (PAG) OIL, SYSTEM CAPACITY . The mentioned diameters for O-rings seals and the tightening torques pertain also to the threaded connections of the refrigerant lines or hoses between the separate components. Only install O-rings seals that are approved for use with Refrigerant R-134a; See Parts department for appropriate o-ring part numbers to use. Checking cooling performance, see A/C REFRIGERANT SYSTEM COOLING PERFORMANCE, TESTING . Checking pressures in refrigerant circuit, see A/C REFRIGERANT SYSTEM, CHECKING PRESSURES . All service and repair work not covered in this Repair Manual: see A/C SYSTEM, REPLACING COMPONENTS .

A/C refrigerant system, component overview

HD = High pressure side

ND = Low pressure side

The following pertains to see scheme 91.

1. A/C Compressor Regulator Valve -N280- Do not remove Checking activation and function. See «ACTIVATION FOR A/C COMPRESSOR REGULATOR VALVE -N280»(/audi/a4/b6-2000-2006/remont/communication-devices/#on-board-diagnostic-obd) . NOTE: The A/C Compressor Regulator Valve -N280- is activated by the A/C control head -E87-, -N280- regulates the pressure on the low pressure side of the compressor.
2. Compressor O-ring seals for compressor: Replace O-ring seals at connections, version. See Parts Catalog Refrigerant lines on compressor, removing and installing, see «REFRIGERANT LINES ON COMPRESSOR, REMOVING AND INSTALLING»(/audi/a4/b6-2000-2006/remont/automatic-hvac-system/#air-conditioning__refrigerant-lines-on-compressor-removing-and) To protect the compressor, the engine should only be started with the refrigerant circuit completely assembled. Remove ribbed belt: See «RIBBED BELT, REMOVING AND INSTALLING»(ref-197056-S06598932702005101100000) for the 1.8L engine, or «RIBBED BELT, REMOVING AND INSTALLING»(ref-197058-S42630607092005101100000) for the 3.0L engine. Compressor removing and installing, see «COMPRESSOR, REMOVING AND INSTALLING (FOR VEHICLES WITH A 4 OR 6 CYL. ENGINE)»(/audi/a4/b6-2000-2006/remont/automatic-hvac-system/#air-conditioning) , or «COMPRESSOR, REMOVING AND INSTALLING (VEHICLES WITH 8 CYL. ENGINE)»(/audi/a4/b6-2000-2006/remont/automatic-hvac-system/#air-conditioning) . Different compressors, depending on country variant and engine, see «REFRIGERANT SYSTEM, SERVICING»(/audi/a4/b6-2000-2006/remont/automatic-hvac-system/#air-conditioning__refrigerant-system-servicing) For vehicle with 8 cyl. engine, the compressor is driven by a shaft rather than a belt, see «COMPRESSOR DRIVE UNIT, CHECKING, REPLACING»(/audi/a4/b6-2000-2006/remont/automatic-hvac-system/#air-conditioning__compressor-drive-unit-checking-replacing) . If a new compressor has been installed or new refrigerant oil has been put into the compressor (e.g. after blowing through the A/C system), the compressor must be turned by hand approx. 10 revolutions. This ensures that the compressor is not damaged when activated.
3. Oil drain plug Denso-compressors have sealing ring installed, always replace Tightening torque: 30 Nm Should only be unscrewed to drain refrigerant oil and with the compressor removed. Turn compressor via pulley, to speed up the oil drainage.
4. Belt pulley/ drive unit compressor Replacing belt pulley, see «BELT PULLEY/DRIVE UNIT OF COMPRESSOR, REPLACING»(/audi/a4/b6-2000-2006/remont/automatic-hvac-system/#air-conditioning) Checking, replacing drive unit-compressor, see «COMPRESSOR DRIVE UNIT, CHECKING, REPLACING»(/audi/a4/b6-2000-2006/remont/automatic-hvac-system/#air-conditioning__compressor-drive-unit-checking-replacing)
5. Pressure relief valve, 10 Nm Do not remove
6. Circuit with valve
7. High Pressure Sensor - G65- Removing- and installing, see «HIGH PRESSURE SENSOR -G65-, REMOVING AND INSTALLING»(/audi/a4/b6-2000-2006/remont/automatic-hvac-system/#air-conditioning__high-pressure-sensor-g65-removing-and) Checking signal, see «TEST STEPS 5 TO 9»(/audi/a4/b6-2000-2006/remont/communication-devices/#on-board-diagnostic-obd)
8. Condenser O-ring seals: Replace O-ring seals at connections, version. See Parts Catalog Refrigerant lines, removing and installing, see «REFRIGERANT LINES FOR CONDENSER, REMOVING AND INSTALLING»(/audi/a4/b6-2000-2006/remont/automatic-hvac-system/#air-conditioning) Condenser removing and installing, see «CONDENSER, REMOVING AND INSTALLING»(/audi/a4/b6-2000-2006/remont/automatic-hvac-system/#air-conditioning)
9. Closing cap With seal Always install
10. Service connection High pressure side For measuring, discharging and recharging.
11. Bolts in refrigerant line Replace O-ring seal, version. See Parts Catalog Tightening torque: 15 Nm
12. Restrictor Installed in connection 11 O-ring seals: 7.5 mm x 1.5 mm Restrictor with O-ring, replacing Removing and installing, see «RESTRICTOR, REMOVING AND INSTALLING»(/audi/a4/b6-2000-2006/remont/automatic-hvac-system/#air-conditioning__restrictor-removing-and-installing) Before installing O-ring seal into restrictor, lubricate O-ring seal with refrigerant oil
13. Evaporator O-ring seals: Replace O-ring seals at connections, version. See Parts Catalog Tightening torque: Hex nut: 25 Nm Refrigerant lines removing and installing, see «REFRIGERANT LINES ON EVAPORATOR FLANGE, REMOVING AND INSTALLING»(/audi/a4/b6-2000-2006/remont/automatic-hvac-system/#air-conditioning) Removing and installing, see «HEATING AND A/C UNIT, DISASSEMBLING AND ASSEMBLING»(/audi/a4/b6-2000-2006/remont/automatic-hvac-system/#air-conditioning__heating-and-ac-unit-disassembling-and)
14. Service connection Low pressure side
15. Closing cap With seal Always install
16. Accumulator O-ring seals: Replace O-ring seals at connections, version. See Parts Catalog Tightening torque: Socket hex bolt on block flange: 25 Nm Removing and installing, see «ACCUMULATOR, REMOVING AND INSTALLING»(/audi/a4/b6-2000-2006/remont/automatic-hvac-system/#air-conditioning)

Connections of refrigerant lines to the components (different versions)

Note. In January 2003, the connections of refrigerant lines to the different components (condenser, evaporator, etc.) have been changed from radial-/axial seals to radial seals (running change in production). Only components of the same type of seal and the O-ring seals provided for them (different versions) may be installed with each other. If components with a different seal are installed, a secure seal cannot be established at the connection points. See Parts Catalog Connection points with a radial/axial seal (up to January 2003, gradually discontinued)

1. Component -A- (condenser) with a connection for radial/axial seal
2. O-ring seal -B- for a connection with radial/axial seal
3. Refrigerant line -C- with a connection with radial/axial seal

1. Connection points with a radial seal (as of January 2003, gradual introduction).

1. Component -A- (condenser) with a connection for radial seal
2. O-ring seal -B- for a connection with radial seal
3. Refrigerant line -C- with a connection with radial seal
4. Guide sleeve -D- (made of plastic) on a connection with radial seal

Refrigerant lines on compressor, removing and installing

Note. With the engine running the compressor is always driven, the compressor has no A/C clutch. For this reason, the engine should only be started when the refrigerant circuit is completely and properly installed. For example; if the refrigerant lines are not connected, when the engine is running the compressor may heat up (via internal heat generation) until the compressor becomes damaged. The following illustrations show a compressor that is installed on the right side of the engine, refrigerant lines with compressors installed on the left side must be removed the same way. For these engines, there is no refrigerant line bracket installed. Close all open lines and connections on compressor with suitable caps (avoid dirt and moisture from entering the system). For vehicles with an 8 cyl. engine, the refrigerant lines are thereby accessible for removal after performing various preliminary steps. See COMPRESSOR, REMOVING AND INSTALLING (VEHICLES WITH 8 CYL. ENGINE) .

1. Discharge A/C refrigerant system. See «A/C REFRIGERANT SYSTEM (R-134A), DISCHARGING»(/audi/a4/b6-2000-2006/remont/automatic-hvac-system/#air-conditioning__ac-refrigerant-system-r-134a-discharging) .
2. Remove noise insulation

See NOISE INSULATION, ASSEMBLY OVERVIEW (except Cabriolet).

For the Cabriolet, see NOISE INSULATION, ASSEMBLY OVERVIEW .

1. Remove bolt -A-, (currently only installed on right hand side compressors)
2. Unscrew bolts -B-.

Installation is reverse of removal, noting the following

1. Check the type of seal on connections and refrigerant lines, they must be designed for the same type of seal. See «CONNECTIONS OF REFRIGERANT LINES TO THE COMPONENTS (DIFFERENT VERSIONS)»(/audi/a4/b6-2000-2006/remont/automatic-hvac-system/#air-conditioning__connections-of-refrigerant-lines-to-the) and the Parts Catalog.

1. Replace O-ring seals -D- and -E-, version.

See Parts Catalog

1. Tighten bolts -B- to: 25 Nm.
2. Tighten bolt -A- to: 25 Nm.

Note. First tighten screw -B-, than tighten clamp -C- with bolt -A- Do not use the O-rings from the shipping caps that are installed on the connections on replacement compressors. Check positions of refrigerant lines -A-, they must be fully engaged in bracket -B- and cannot come in contact with other components.

1. Discharge A/C refrigerant system. See «A/C REFRIGERANT SYSTEM (R-134A), DISCHARGING»(/audi/a4/b6-2000-2006/remont/automatic-hvac-system/#air-conditioning__ac-refrigerant-system-r-134a-discharging) .
2. Disconnect refrigerant lines from compressor. See «REFRIGERANT LINES ON COMPRESSOR, REMOVING AND INSTALLING»(/audi/a4/b6-2000-2006/remont/automatic-hvac-system/#air-conditioning__refrigerant-lines-on-compressor-removing-and) .
3. Remove compressor from bracket. See «COMPRESSOR, REMOVING AND INSTALLING FROM BRACKET»(/audi/a4/b6-2000-2006/remont/automatic-hvac-system/#air-conditioning) .

Installation is reverse of removal, noting the following

1. Check the type of seal on connections and refrigerant lines, they must be designed for the same type of seal. See «CONNECTIONS OF REFRIGERANT LINES TO THE COMPONENTS (DIFFERENT VERSIONS)»(/audi/a4/b6-2000-2006/remont/automatic-hvac-system/#air-conditioning__connections-of-refrigerant-lines-to-the) and Before installing compressor: NOTE: Removed compressor contains an unspecified amount of refrigerant oil, therefore observe notes for replacing compressor.
2. Tightening torques and O-ring seals, see «COMPRESSOR, REMOVING AND INSTALLING FROM BRACKET»(/audi/a4/b6-2000-2006/remont/automatic-hvac-system/#air-conditioning) and «REFRIGERANT LINES ON COMPRESSOR, REMOVING AND INSTALLING»(/audi/a4/b6-2000-2006/remont/automatic-hvac-system/#air-conditioning__refrigerant-lines-on-compressor-removing-and)
3. Install all removed components again.
4. Evacuate refrigerant circuit and recharge again.
5. Run A/C system after installing compressor. See «A/C SYSTEM, RUNNING AFTER INSTALLING COMPRESSOR»(/audi/a4/b6-2000-2006/remont/automatic-hvac-system/#air-conditioning__ac-system-running-after-installing-compressor) .

Removing (compressor driven via a shaft)

1. Evacuate the refrigerant circuit: See «A/C REFRIGERANT SYSTEM (R-134A), EVACUATING AND RECHARGING»(/audi/a4/b6-2000-2006/remont/automatic-hvac-system/#air-conditioning__ac-refrigerant-system-r-134a-evacuating-and) .
2. Syphon power steering hydraulic fluid from reservoir using VAG1358A.

Scheme 14

1. Open cap of coolant reservoir.
2. Remove left front wheel.
3. For vehicles with parking heater, remove screws (arrows) for exhaust pipe of parking-/auxiliary heater at noise insulation.
4. Remove quick-release screws -1-, remove screws -2- and remove noise insulation.
5. Remove front bumper: See «FRONT BUMPER, REMOVING AND INSTALLING»(/audi/a4/b6-2000-2006/remont/exterior-body-panels/#bumpers-except-cabriolet) (except Cabriolet). For the Cabriolet, see «FRONT BUMPER, REMOVING AND INSTALLING»(/audi/a4/b6-2000-2006/remont/exterior-body-panels/#bumpers-cabriolet).
6. Remove left air guide -arrow- in front of auxiliary cooler.
7. Remove right air guide -arrow- in front of auxiliary cooler.
8. Place a VAG1306 Drip Tray underneath engine.
9. Remove drain plug -arrow- on coolant regulator housing and drain coolant from engine.
10. Disconnect lower coolant hose from radiator -arrow- and drain residual coolant.
11. Place an oil pan underneath hydraulic lines to rear coolant coil.
12. Disconnect hydraulic lines to cooling coil at rear of bumper (arrows).
13. Remove cover -1- in engine compartment (right side).
14. Detach Evaporative Emission (EVAP) Canister Purge Regulator Valve -N80- -1- at air guide.
15. Remove bolts (arrows). see scheme 104
16. Remove air guide -2-.
17. Disconnect top coolant hose (arrow) from radiator.
18. Remove cover -1- in engine compartment (left side).
19. Disconnect electrical harness connectors -1- and -2- from bracket and disconnect them.
20. Expose wires to lock carrier.
21. Disconnect electrical harness connector (arrow) for headlights at both sides of the vehicle.
22. Disconnect electrical harness connector -arrow- for left and right airbag sensors on lock carrier.
23. Expose cables.
24. Remove hood release cable at radiator support. See «HOOD CABLE, ASSEMBLY OVERVIEW»(/audi/a4/b6-2000-2006/remont/exterior-body-panels/#hood-lids-except-cabriolet__hood-cable-assembly-overview) (except Cabriolet). For the Cabriolet, see «REMOVING AND INSTALLING HOOD LOCK CABLE»(/audi/a4/b6-2000-2006/remont/exterior-body-panels/#hood-lids-cabriolet__removing-and-installing-hood-lock-cable).
25. Disconnect electrical harness connector (arrow) for right fan.
26. Remove air guides at left and right of radiator (arrows). NOTE: To prevent damage at condenser as well as at the refrigerant lines/hoses, it must be observed that the lines and are not over-stretched, kinked or bent.
27. Unbolt refrigerant line (arrow) leading to A/C compressor.
28. Unbolt refrigerant line (arrow) leading to A/C evaporator.
29. Remove bolts (arrows) at left and right side of bumper.
30. Pull off hood seal from lock carrier and fender edges.
31. Remove bolts at left and right of impact absorbers (arrows). NOTE: A second technician is required to remove the lock carrier.
32. Remove lock carrier and set it aside so it cannot topple.
33. Remove rear engine cover (arrows).
34. Position 10-222A engine support bridge onto bolted flange of fenders.
35. Insert hooks of engine support bridge into engine lifting eyelet.
36. Pre-tension engine slightly using spindle of engine support bridge, do not lift.
37. Disconnect coolant hoses at positions indicated by arrows.
38. Disconnect coolant hose at coolant regulator housing (arrow). WARNING: Do not bend or kink A/C lines.
39. Unscrew retaining clamp -arrow- for refrigerant line at right bracket.
40. Remove left bracket for refrigerant line (arrows).
41. Remove bolts -1- and -2-.
42. Detach refrigerant lines from A/C compressor and plug open connections, see «REFRIGERANT LINES ON COMPRESSOR, REMOVING AND INSTALLING»(/audi/a4/b6-2000-2006/remont/automatic-hvac-system/#air-conditioning__refrigerant-lines-on-compressor-removing-and).
43. Remove nuts -1- to -4- for left and right stabilizer mounts.
44. Remove nut -2-.
45. Loosen bolts -1- and -3- and remove left engine console.
46. Disconnect electrical harness connector -1- on left engine mount.
47. Remove nut -2- and remove engine mount. see scheme 125 NOTE: Illustration is shown with engine removed.
48. Remove bolts -1- and -2-. NOTE: To prevent oil from escaping, the hose (arrow) remains connected to power steering. see scheme 126
49. Unbolt guide tube for oil dipstick at cylinder head (arrow) and remove it upward.
50. Remove left engine support (arrows).
51. Hold compressor drive shaft -A- in place using open-end wrench and turn compressor drive unit -B- in direction of arrow -C-. see scheme 129 NOTE: Drive shaft -A- must not be turned. Drive shaft -A- can be slid into drive wheel through boot - E- after loosening bolts.
52. Disconnect 2-pin harness connector to A/C Compressor Regulator Valve -N280-.
53. Remove bolts -D- (tightening torque 25 Nm). see scheme 130
54. Remove compressor toward front.
55. Remove bushings -F- from compressor if necessary.

Before installing compressor

Note. Removed compressor contains an unspecified amount of refrigerant oil, therefore observe notes for replacing compressor.

Scheme 15

1. Check the type of seal on connections and refrigerant lines, they must be designed for the same type of seal. See «CONNECTIONS OF REFRIGERANT LINES TO THE COMPONENTS (DIFFERENT VERSIONS)»(/audi/a4/b6-2000-2006/remont/automatic-hvac-system/#air-conditioning__connections-of-refrigerant-lines-to-the) and
2. Install compressor drive shaft (into drive wheel of engine) and check seating as well as the pertaining boot. See «COMPRESSOR DRIVE SHAFT, REMOVING AND INSTALLING»(/audi/a4/b6-2000-2006/remont/automatic-hvac-system/#air-conditioning).
3. Remove bushings -C- from compressor bracket if necessary. see scheme 131
4. Thoroughly clean contact surfaces -A- and -B- on bracket (and contact surfaces on compressor).
5. Install bushings -C- into compressor bracket. NOTE: Ensure that bushings -C- are properly seated and contact surfaces are clean. Incorrectly installed bushings, soiled or damaged contact surfaces can lead to misalignment between compressor and engine. Misalignment leads to damage at drive shaft or at compressor over running time.
6. Install compressor onto bracket using bolts -D- (and washers -E-) (tightening torque 25 Nm). see scheme 132
7. Install refrigerant lines on compressor (tightening torque of bolts -A-25 Nm). Dimensions of O-ring seals -B- and -C- as well as further notes, see «REFRIGERANT LINES ON COMPRESSOR, REMOVING AND INSTALLING»(/audi/a4/b6-2000-2006/remont/automatic-hvac-system/#air-conditioning__refrigerant-lines-on-compressor-removing-and).
8. After installing a new compressor or filling fresh refrigerant oil (for example, after blowing through the A/C system to prevent damage on compressor), turn the compressor 10 revolutions by hand via the compressor drive unit-B- in direction of arrow -C- before tightening the drive shaft. see scheme 133
9. Tighten drive shaft, hold compressor drive shaft -A- in place using open-end wrench and turn compressor drive unit -B- in direction of arrow -D- (tightening torque 60 Nm). NOTE: Drive shaft -A- must not be turned. see scheme 134 After installing drive shaft -A-, check installation position of boot -E-.
10. Install all removed components.
11. Evacuate and recharge refrigerant circuit. See «A/C REFRIGERANT SYSTEM (R-134A), EVACUATING AND RECHARGING»(/audi/a4/b6-2000-2006/remont/automatic-hvac-system/#air-conditioning__ac-refrigerant-system-r-134a-evacuating-and).
12. Run A/C system after installing compressor. See «A/C SYSTEM, RUNNING AFTER INSTALLING COMPRESSOR»(/audi/a4/b6-2000-2006/remont/automatic-hvac-system/#air-conditioning__ac-system-running-after-installing-compressor)

A/C system, running after installing compressor

1. If a new compressor has been installed or fresh refrigerant oil has been filled into the compressor (e.g. after blowing through the A/C system), the compressor must be turned by hand approx. 10 revolutions. This ensures that the compressor will not be damaged when first activated.
2. Only start engine after refrigerant circuit has been assembled.
3. Only start engine with system recharged. See «A/C REFRIGERANT SYSTEM (R-134A), EVACUATING AND RECHARGING»(/audi/a4/b6-2000-2006/remont/automatic-hvac-system/#air-conditioning__ac-refrigerant-system-r-134a-evacuating-and) .

Note. The compressor is always driven by the belt pulley (no A/C clutch)

1. The compressor is equipped with an "internal oil circuit", this prevents compressor damage in the event that the system is empty. A residual amount of refrigerant oil must be in the compressor as a requirement for internal lubrication.
2. The engine should only be started when the refrigerant circuit is completely and properly installed. For example; if the refrigerant lines are not connected, when the engine is running the compressor may heat up (via internal heat generation) until the compressor becomes damaged. The A/C Compressor Regulator Valve -N280- is not activated when the system is empty, and the compressor runs at idle with the engine.
3. The necessary oil to lubricate the compressor is not transferred, since no refrigerant is available.
4. In order to avoid compressor damage, the compressor is lubricated by an "internal oil circuit". If it is necessary to start the engine with a discharged refrigerant circuit
5. The refrigerant circuit must be completely assembled.
6. At least one quarter of designated refrigerant oil for this circuit must be in the compressor.
7. Engine speed should not increase above 2500 RPM.
8. The engine should only run as long as absolutely necessary
9. Observe the following when starting the engine after recharging the refrigerant circuit: - Start engine with compressor switched off ("ECON" mode) and wait until idle speed has stabilized. - Open dash panel vents. - Select "Lo" on A/C Control Head -E87-. - Now switch on compressor ("AUTO" mode) and run for at least 5 minutes with the engine at idle.

Disconnecting

1. Remove plenum cover.
2. Discharge A/C refrigerant system. See «A/C REFRIGERANT SYSTEM (R-134A), DISCHARGING»(/audi/a4/b6-2000-2006/remont/automatic-hvac-system/#air-conditioning__ac-refrigerant-system-r-134a-discharging) .
3. Remove nuts -A- (tightening torque 25 Nm).
4. Detach refrigerant lines from evaporator and seal off all open connections.

Note. To seal off all open connections on evaporator -D-, sealing caps from a replacement evaporator can be used (avoid dirt and moisture from entering the system).

Connecting

Installation is reverse of removal, noting the following

1. Replace O-ring seals -B- and -C-, version. See Parts Catalog
2. Install refrigerant lines free of stress.
3. After tightening refrigerant lines make sure that grommet - E- and line grommet -F- is properly installed. see scheme 135
4. Check the type of seal on connections and refrigerant lines, they must be designed for the same type of seal, see «CONNECTIONS OF REFRIGERANT LINES TO THE COMPONENTS (DIFFERENT VERSIONS)»(/audi/a4/b6-2000-2006/remont/automatic-hvac-system/#air-conditioning__connections-of-refrigerant-lines-to-the) and the Parts Catalog
5. Check position of refrigerant lines to evaporator, they should not come in contact with other components.
6. Evacuate refrigerant circuit and recharge again. See «A/C REFRIGERANT SYSTEM COOLING PERFORMANCE, TESTING»(/audi/a4/b6-2000-2006/remont/automatic-hvac-system/#air-conditioning).

1. Remove noise insulation

See NOISE INSULATION, ASSEMBLY OVERVIEW (except Cabriolet).

For the Cabriolet, see NOISE INSULATION, ASSEMBLY OVERVIEW

1. Remove complete front bumper

See FRONT BUMPER, REMOVING AND INSTALLING (except Cabriolet).

For the Cabriolet, see FRONT BUMPER, REMOVING AND INSTALLING

1. Discharge A/C refrigerant system. See «A/C REFRIGERANT SYSTEM (R-134A), DISCHARGING»(/audi/a4/b6-2000-2006/remont/automatic-hvac-system/#air-conditioning__ac-refrigerant-system-r-134a-discharging).
2. Remove bolts -A- (tightening torque 20 Nm). see scheme 137
3. Remove refrigerant line from condenser.

Note. Close all open lines and connections on condenser with suitable caps (avoid dirt and moisture from entering the system).

Installation is reverse of removal, noting the following

1. Replace O-ring seals -B- and -C-, version.

See Parts Catalog

1. Check the type of seal on connections and refrigerant lines, they must be designed for the same type of seal. See «CONNECTIONS OF REFRIGERANT LINES TO THE COMPONENTS (DIFFERENT VERSIONS)»(/audi/a4/b6-2000-2006/remont/automatic-hvac-system/#air-conditioning__connections-of-refrigerant-lines-to-the) and Parts Catalog .

Scheme 16

1. Evacuate refrigerant circuit and recharge again. See «A/C REFRIGERANT SYSTEM, TESTING»(/audi/a4/b6-2000-2006/remont/automatic-hvac-system/#air-conditioning) .

1. Discharge A/C refrigerant system. See «A/C REFRIGERANT SYSTEM (R-134A), DISCHARGING»(/audi/a4/b6-2000-2006/remont/automatic-hvac-system/#air-conditioning__ac-refrigerant-system-r-134a-discharging) .
2. Disconnect refrigerant lines from condenser. See «REFRIGERANT LINES FOR CONDENSER, REMOVING AND INSTALLING»(/audi/a4/b6-2000-2006/remont/automatic-hvac-system/#air-conditioning) .
3. Remove air duct between bumper and condenser.
4. Disconnect connector from High Pressure Sensor -G65- -B
5. Remove bolts -A- (tightening torque 5 Nm).

Installation is the reverse of removal.

1. Check the type of seal on connections and refrigerant lines, they must be designed for the same type of seal. See «CONNECTIONS OF REFRIGERANT LINES TO THE COMPONENTS (DIFFERENT VERSIONS)»(/audi/a4/b6-2000-2006/remont/automatic-hvac-system/#air-conditioning__connections-of-refrigerant-lines-to-the) and Parts Catalog .

Removed condenser contains refrigerant oil which must be restored to the refrigerant system (with new condenser).

Restrictor, removing and installing

Note. Up to model year 2001, restrictors with yellow color markings were installed (diameter of hole/narrow neck 1.54 mm). As of model year 2002, restrictors with red color markings are installed (diameter of hole/narrow neck 1.42 mm). Changing the restrictor does not change the filling quantity of R-134a refrigerant in this vehicle.

1. Discharge A/C refrigerant system. See «A/C REFRIGERANT SYSTEM (R-134A), DISCHARGING»(/audi/a4/b6-2000-2006/remont/automatic-hvac-system/#air-conditioning__ac-refrigerant-system-r-134a-discharging) .
2. Disconnect refrigerant lines by unscrewing threaded connection -A- (seal off open connections).
3. Pull restrictor out of refrigerant line -B- using needle nose pliers.

Note. Only install same version restrictor (color). Restrictors with different colors have different diameters in restrictor hole

1. Install restrictor -B- on proper side (arrow on restrictor points in direction of evaporator).

1. The restrictor must fit in refrigerant line without play.

1. Check O-ring seal -C- (7.5 mm x 1.5 mm) for correct seating in groove. see scheme 141
2. Replace O-ring seal -D-, version.

See Parts Catalog

1. Check the type of seal on connections and refrigerant lines, they must be designed for the same type of seal. See «CONNECTIONS OF REFRIGERANT LINES TO THE COMPONENTS (DIFFERENT VERSIONS)»(/audi/a4/b6-2000-2006/remont/automatic-hvac-system/#air-conditioning__connections-of-refrigerant-lines-to-the) and Parts Catalog.
2. Before installing O-ring seal into restrictor lubricate O-ring seal with refrigerant oil.
3. Install refrigerant lines free of stress.
4. Tighten threaded connection -A- to: 15 Nm. see scheme 142

Scheme 17

Note. After tightening the threaded connection, check refrigerant lines position lines should not touch other components.

1. Evacuate refrigerant circuit and recharge again. See «A/C REFRIGERANT SYSTEM, TESTING»(/audi/a4/b6-2000-2006/remont/automatic-hvac-system/#air-conditioning) .

1. Discharge A/C refrigerant system. See «A/C REFRIGERANT SYSTEM (R-134A), DISCHARGING»(/audi/a4/b6-2000-2006/remont/automatic-hvac-system/#air-conditioning__ac-refrigerant-system-r-134a-discharging)
2. Remove complete front bumper

See FRONT BUMPER, REMOVING AND INSTALLING (except Cabriolet).

For the Cabriolet, see FRONT BUMPER, REMOVING AND INSTALLING .

1. Move the lock carrier into service position

See LOCK CARRIER, MOVING TO SERVICE POSITION (excpet Cabriolet).

For the Cabriolet, see LOCK CARRIER, MOVING TO SERVICE POSITION .

1. Remove charge air cooler or the secondary air injection pump.

For 1.8L engine, see CHARGE AIR SYSTEM WITH TURBOCHARGER, SERVICING . For 3.0L V6, see SECONDARY AIR SYSTEM .

1. Remove bolts -A- and remove refrigerant lines -B- and -C-. see scheme 143
2. Unscrew bolts -A-. see scheme 144
3. Loosen notch on bracket for accumulator -B- from body
4. Remove accumulator with bracket.
5. Loosen screw -C- and remove accumulator from bracket -D

Note. Seal all open connections. The connection of the refrigerant lines differs, depending on engine type: Keep accumulator closed as long as possible; do not remove caps until just before installing. The accumulator contains a desiccant which will become saturated with moisture in a short time if accumulator is left open. This makes the accumulator unusable.

Installation is reverse of removal, noting the following

1. Check the type of seal on connections and refrigerant lines, they must be designed for the same type of seal. See «CONNECTIONS OF REFRIGERANT LINES TO THE COMPONENTS (DIFFERENT VERSIONS)»(/audi/a4/b6-2000-2006/remont/automatic-hvac-system/#air-conditioning__connections-of-refrigerant-lines-to-the) and Parts Catalog .

Note. The connection on the accumulator may be marked with "IN" (from evaporator) and "OUT" (to compressor). Removed accumulator contains refrigerant oil which must be restored to the refrigerant system (with new accumulator). The adaptation of the oil capacity depends on the type of repair and the state of the components

For example if the accumulator was damaged (no refrigerant escaped, no moisture or dirt entered the system), the air conditioning system can be repaired by weighing the old and the new accumulator: Fill new accumulator with refrigerant oil, until the weight of the removed accumulator is reached.

If a undefined amount of refrigerant oil escaped or dirt and moisture entered the system, clean refrigerant circuit with compressed air and nitrogen.

1. Install accumulator in bracket -D-. see scheme 146
2. Hang bracket -D- with nose -B- engaged.
3. Mount screws -A- and tighten with 8 Nm.
4. Replace O-ring seals -D-, version.

=> Parts Catalog

Scheme 18

1. Turn accumulator so that both refrigerant lines -B- and -C- can be stress free installed in the accumulator. Observe correct connection assignment.
2. Mount refrigerant line with screw -A- on accumulator (tightening torque 25 Nm). When tightening refrigerant lines to accumulator, hold accumulator e.g. with oil filter strap (to avoid accumulator from turning).
3. Tighten bolt -C- (tightening torque 8 Nm).
4. Install all removed components again.
5. Evacuate refrigerant circuit and recharge again, see «A/C REFRIGERANT SYSTEM, TESTING»(/audi/a4/b6-2000-2006/remont/automatic-hvac-system/#air-conditioning) .

A/C refrigerant R-134a, system capacity

Note. The repair manual "A/C system with refrigerant R134a" can be found (e.g. for rest of world) in "ELSA" under "Internet" (the globe), "Audi" (the flag with your language), "Technical Information" (arrow). Always refer to safety precautions. See SAFETY PRECAUTIONS . When charging the system on the high pressure side, always use the maximum amount of A/C refrigerant, as some of the refrigerant remains in the hoses of the refrigerant recovery, recycling and recharging unit. The compressor manufacturer Nippondenso has changed its name to "Denso". To determine what compressor is used (Zexel, Sanden, Nippondenso/Denso) see Parts department. A sticker with data about the capacity and the type of refrigerant is located in the engine compartment.

1. Features of the refrigerant system
2. Restrictor (yellow or red color marking)
3. Accumulator
4. "Denso" compressor with A/C compressor regulator valve -N280- (without A/C clutch) see Parts department.
5. Restrictors with different diameters are available as replacement parts, yellow color marking 1.54 mm, red color marking 1.42 mm.
6. Only restrictors with red or yellow color markings should be installed so that the cooling performance of the climate control system is not changed. As of m.y. 2002, only restrictors with red color markings are installed in the Audi A4, if a restrictor with a yellow color marking is installed in this vehicle, there should be no change in system capacity for this vehicle, see Parts department.
7. Different compressors are installed depending on the version, see Parts department.

Refrigerant (PAG) oil, system capacity

1. PAG oil (Polyalkylene glycol) absorbs moisture very rapidly. Always use specified PAG oil from sealed container and always re-seal container immediately after use.
2. PAG oil from a container that has been left open for some time is no longer usable.
3. The manufacturer for Nippondenso compressors has changed its name to "Denso".
4. The refrigerant oil capacity for a replacement compressor represents the total refrigerant oil capacity of the refrigerant system. When installing a replacement compressor, it is necessary to compensate for the amount of refrigerant remaining in the system (compressor removed) by draining a certain amount of oil from the replacement compressor.
5. When pouring out refrigerant oil from the replacement or faulty compressor, a small amount of oil remains in the compressor, about 20 to 30cm 3 (1.2 to 1.8 in 3 ). This amount of oil does not impair the function of the A/C system and does not need to be considered.
6. When A/C is switched on for the first time, the refrigerant oil is distributed throughout the entire system.
7. When replacing A/C system components, add appropriate amount of refrigerant oil to component.

Note. The refrigerant oil capacity for a replacement compressor represents the total oil capacity of the refrigerant system. When installing a replacement compressor, it is necessary to compensate for the amount of refrigerant remaining in the system (compressor removed) by draining a certain amount of oil from the replacement compressor. Depending on engine and production period for the A4, different compressors were installed: See Parts department.

Heating and A/C unit, component overview

The following list pertains to. see scheme 151

1. Heating and A/C unit Removing and installing, see «HEATING AND A/C UNIT, REMOVING AND INSTALLING»(/audi/a4/b6-2000-2006/remont/automatic-hvac-system/#air-conditioning) Heating elements and air ducts removing and installing, see «HEATING ELEMENTS AND AIR DUCTS, REMOVING AND INSTALLING»(/audi/a4/b6-2000-2006/remont/automatic-hvac-system/#air-conditioning__heating-elements-and-air-ducts-removing) Disassembling and assembling, see «HEATING AND A/C UNIT, DISASSEMBLING AND ASSEMBLING»(/audi/a4/b6-2000-2006/remont/automatic-hvac-system/#air-conditioning__heating-and-ac-unit-disassembling-and) .
2. Actuator for temperature flap left -V158- With Potentiometer-actuator for temperature flap left -G220- Color designation of lever: red Removing and installing, see «ACTUATOR FOR TEMPERATURE FLAP LEFT -V158-, REMOVING AND INSTALLING»(/audi/a4/b6-2000-2006/remont/automatic-hvac-system/#air-conditioning__actuator-for-temperature-flap-left-v158)
3. Bolt
4. Left Footwell Vent Temperature Sensor - G261- Removing and installing, see «LEFT FOOTWELL VENT TEMPERATURE SENSOR -G261-, REMOVING AND INSTALLING»(/audi/a4/b6-2000-2006/remont/automatic-hvac-system/#air-conditioning__left-footwell-vent-temperature-sensor-g261)
5. Right Footwell Vent Temperature Sensor - G262- Removing and installing, see «RIGHT FOOTWELL VENT TEMPERATURE SENSOR - G262-, REMOVING AND INSTALLING»(/audi/a4/b6-2000-2006/remont/automatic-hvac-system/#air-conditioning__right-footwell-vent-temperature-sensor)
6. Cable ties
7. Support for wiring harness
8. Air conditioning wiring harness
9. Evaporator Vent Temperature Sensor - G263- Removing and installing, see «EVAPORATOR VENT TEMPERATURE SENSOR -G263-, REMOVING AND INSTALLING»(/audi/a4/b6-2000-2006/remont/automatic-hvac-system/#air-conditioning)
10. Actuator for temperature flap right -V159- With Potentiometer - actuator for temperature flap right -G221- Color designation of lever: violet Removing and installing, see «ACTUATOR FOR TEMPERATURE FLAP RIGHT -V159-, REMOVING AND INSTALLING»(/audi/a4/b6-2000-2006/remont/automatic-hvac-system/#air-conditioning__actuator-for-temperature-flap-right-v159)
11. Central Air Flap Motor -V70- With Central Flap Motor Position Sensor -G112- Color designation of curved washer: white Removing and installing, see «CENTRAL AIR FLAP MOTOR -V70-, REMOVING AND INSTALLING»(/audi/a4/b6-2000-2006/remont/automatic-hvac-system/#air-conditioning)
12. Defroster Flap Motor - V107- With Defroster Flap Motor Position Sensor -G135- Color designation of lever: dark green Removing and installing, see «DEFROSTER FLAP MOTOR -V107-, REMOVING AND INSTALLING»(/audi/a4/b6-2000-2006/remont/automatic-hvac-system/#air-conditioning)
13. Recirculation Flap Motor -V113- With Recirculation- Flap Motor Position Sensor -G143- Color designation of lever: blue Removing and installing, see «RECIRCULATION FLAP MOTOR -V113-, REMOVING AND INSTALLING»(/audi/a4/b6-2000-2006/remont/automatic-hvac-system/#air-conditioning)
14. Air Flow Flap Motor -V71- With Back Pressure Flap Motor Position Sensor -G113- Color designation of curved washer: light blue Removing and installing, see «DEFROSTER FLAP MOTOR -V107-, REMOVING AND INSTALLING»(/audi/a4/b6-2000-2006/remont/automatic-hvac-system/#air-conditioning)
15. Lever
16. Lever
17. Control module for fresh air blower -J126- and Fresh Air Blower -V2- Removing and installing, see «CONTROL MODULE FOR FRESH AIR BLOWER -J126- AND FRESH AIR BLOWER -V2-, REMOVING AND INSTALLING»(/audi/a4/b6-2000-2006/remont/automatic-hvac-system/#air-conditioning) The Control module for fresh air blower -J126- is integrated in the Fresh Air Blower -V2-, and cannot be replaced separately.
18. Fresh Air Intake Duct Temperature Sensor -G89- Removing and installing, see «FRESH AIR INTAKE DUCT TEMPERATURE SENSOR -G89-, REMOVING AND INSTALLING»(/audi/a4/b6-2000-2006/remont/automatic-hvac-system/#air-conditioning)

Heating elements and air ducts, removing and installing

The following list pertains to see scheme 152.

1. Air conditioning unit Removing and installing, see «HEATING AND A/C UNIT, REMOVING AND INSTALLING»(/audi/a4/b6-2000-2006/remont/automatic-hvac-system/#air-conditioning) Disassembling and assembling, see «HEATING AND A/C UNIT, DISASSEMBLING AND ASSEMBLING»(/audi/a4/b6-2000-2006/remont/automatic-hvac-system/#air-conditioning__heating-and-ac-unit-disassembling-and) .
2. Coolant line Return tube
3. Coolant line Supply tube
4. Bracket for refrigerant lines
5. Bolt
6. Protection cover for coolant lines
7. Clamps Always replace Check for proper seating Tightening torque for bolts: 2.5 Nm
8. O-ring seal Always replace
9. Heater core Removing and installing, see «HEATER CORE, REMOVING AND INSTALLING»(/audi/a4/b6-2000-2006/remont/automatic-hvac-system/#air-conditioning)
10. Cover Opening only on vehicles with air conditioner, installed without auxiliary heating element The cap is the same as cap on heater element for additional heater, except openings for connectors are sealed (air tight)
11. Heater element for auxiliary heater -Z35- Only installed on vehicles with Diesel engine Not applicable in USA
12. Sealing plug Only installed on vehicles without glove compartment cooling
13. Air duct for glove compartment Only installed on vehicles without glove compartment cooling
14. Flange for evaporator drain The evaporator drain remain in the vehicle during removal of air conditioner

Heating and A/C unit, disassembling and assembling

1. Remove components from air conditioner unit. See «HEATING ELEMENTS AND AIR DUCTS, REMOVING AND INSTALLING»(/audi/a4/b6-2000-2006/remont/automatic-hvac-system/#air-conditioning__heating-elements-and-air-ducts-removing) .
2. Remove heating elements and air ducts from air conditioning unit. See «HEATING ELEMENTS AND AIR DUCTS, REMOVING AND INSTALLING»(/audi/a4/b6-2000-2006/remont/automatic-hvac-system/#air-conditioning__heating-elements-and-air-ducts-removing) .

The following list pertains to see scheme 153.

1. Bolt
2. Intake housing Do not disassemble further With recirculated air flap and two back pressure/fresh air flaps.
3. Bracket For refrigerant lines of evaporator
4. Air duct Constructed of upper and lower part.
5. Evaporator Check insulation of refrigerant lines, must be completely installed. Removing and installing, see «EVAPORATOR, REMOVING AND INSTALLING»(/audi/a4/b6-2000-2006/remont/automatic-hvac-system/#air-conditioning__evaporator-removing-and-installing) Evaporator seal installing, see «EVAPORATOR, REMOVING AND INSTALLING»(/audi/a4/b6-2000-2006/remont/automatic-hvac-system/#air-conditioning__evaporator-removing-and-installing) Check the type of seal on connections and refrigerant lines, they must be designed for the same type of seal. See «CONNECTIONS OF REFRIGERANT LINES TO THE COMPONENTS (DIFFERENT VERSIONS)»(/audi/a4/b6-2000-2006/remont/automatic-hvac-system/#air-conditioning__connections-of-refrigerant-lines-to-the) and Parts Catalog . Removed evaporator contains refrigerant oil which must be restored to the refrigerant system.
6. Sealing gasket for evaporator Evaporator seal installing, see «EVAPORATOR, REMOVING AND INSTALLING»(/audi/a4/b6-2000-2006/remont/automatic-hvac-system/#air-conditioning__evaporator-removing-and-installing)
7. Air distribution housing Do not disassemble With temperature flaps and air distribution flaps The coupling elements of temperature flaps 1 to temperature flaps 2, that are installed in the air distribution housing are visible when air distributor housing is removed. See «COUPLING ELEMENT BETWEEN TEMPERATURE FLAPS "1" AND "2"»(/audi/a4/b6-2000-2006/remont/automatic-hvac-system/#air-conditioning__coupling-element-between-temperature-flaps-1) .
8. Footwell vents front Removing and installing, see «FOOTWELL VENTS FRONT, REMOVING AND INSTALLING»(/audi/a4/b6-2000-2006/remont/automatic-hvac-system/#air-conditioning)

1. Hose clamps 3093 or 3094
2. Compressed air gun, standard
3. V.A.G 1274 hand pump with adapters

1. Remove plenum cover.
2. Discharge A/C refrigerant system. See «A/C REFRIGERANT SYSTEM (R-134A), DISCHARGING»(/audi/a4/b6-2000-2006/remont/automatic-hvac-system/#air-conditioning__ac-refrigerant-system-r-134a-discharging) .
3. Disconnect battery and remove.

Note. Obtain radio code before disconnecting battery. On vehicles with power seats, move the seats back as far as possible before disconnecting the battery. Take a note of the length and assignment of bolts during removal. All cable ties opened or cut during air conditioner removal must be reinstalled at the same locations during installation.

1. Release pressure in coolant system by opening cap on coolant expansion tank.
2. Mark allocation of the coolant hoses -A- and -B-.
3. Clamp off and disconnect both coolant hoses leading to heater core in air conditioner unit (e.g. using V.A.G 3094)

Note. The coolant hoses must be re-installed in the correct positions

Coolant hose -A- supply from cylinder head.

Coolant hose -B- return to water pump.

Scheme 19

1. Bleed cooling circuit

See COOLING SYSTEM, DRAINING AND FILLING (1.8L Turbo), or COOLANT, DRAINING AND REFILLING (3.0L V6), or COOLING SYSTEM, DRAINING AND FILLING WITH COOLANT (4.2L V8).

Scheme 20

1. Place container under connection -A-.
2. Place a piece of hose on connection -B- and carefully blow out coolant from heater core with compressed air.
3. Remove grommet -C-.
4. Remove refrigerant lines from evaporator, see «REFRIGERANT LINES ON EVAPORATOR FLANGE, REMOVING AND INSTALLING»(/audi/a4/b6-2000-2006/remont/automatic-hvac-system/#air-conditioning) and secure (e.g. with cable tie) so they do not interfere during installation.
5. Remove grommet -E-.

Scheme 21

Note. Seal all open connections. To seal off all open connections on evaporator, sealing caps from a replacement evaporator can be used (preventing dirt and moisture from entering the system).

1. Protect driver and passenger seat using seat cover.
2. Remove glove compartment, driver's side storage compartment, center console and instrument panel: See «INTERIOR EQUIPMENT - EXCEPT CABRIOLET»(/audi/a4/b6-2000-2006/remont/mirrors/#interior-equipment-except-cabriolet) . For the Cabriolet, see «INTERIOR EQUIPMENT - CABRIOLET»(ref-197209) .
3. Remove instrument panel: See «INSTRUMENT PANEL, REMOVING AND INSTALLING»(/audi/a4/b6-2000-2006/remont/gauges-instrument-panels/#interior-trim-except-cabriolet__instrument-panel-removing-and-installing) (except Cabriolet). For the Cabriolet, see «INSTRUMENT PANEL, REMOVING AND INSTALLING»(/audi/a4/b6-2000-2006/remont/gauges-instrument-panels/#interior-trim-cabriolet) .

Note. To prevent the instrument panel shell from damage, instrument panel should be placed on a clean work bench which is covered with clean cardboard.

1. Remove brace -A- for central tube (passenger side on center tunnel) See «INTERIOR TRIM - EXCEPT CABRIOLET»(/audi/a4/b6-2000-2006/remont/gauges-instrument-panels/#interior-trim-except-cabriolet) or «INTERIOR TRIM - CABRIOLET»(/audi/a4/b6-2000-2006/remont/gauges-instrument-panels/#interior-trim-cabriolet) .
2. Remove accelerator pedal module.

See appropriate Fuel Supply article under FUEL SYSTEM.

Vehicles with knee bolster

1. Remove right support (located above clutch pedal). See «STORAGE COMPARTMENTS AND COVERS»(/audi/a4/b6-2000-2006/remont/mirrors/#interior-equipment-except-cabriolet) (except Cabriolet). For the Cabriolet, see «STORAGE COMPARTMENTS AND COVERS»(ref-197209-S10437329772005101300000) .

Scheme 22

Scheme 23

1. Remove bolts -A- and -B- between brace -C- and the air conditioner.
2. Remove brace -C- for central tube (driver's side on center tunnel). See «INTERIOR TRIM - EXCEPT CABRIOLET»(/audi/a4/b6-2000-2006/remont/gauges-instrument-panels/#interior-trim-except-cabriolet) or «INTERIOR TRIM - CABRIOLET»(/audi/a4/b6-2000-2006/remont/gauges-instrument-panels/#interior-trim-cabriolet) .
3. Remove front footwell vent. See «FOOTWELL VENTS FRONT, REMOVING AND INSTALLING»(/audi/a4/b6-2000-2006/remont/automatic-hvac-system/#air-conditioning) .
4. Remove bolt for brake pedal mounting bracket (and clutch pedal) from central tube. See «INTERIOR TRIM - EXCEPT CABRIOLET»(/audi/a4/b6-2000-2006/remont/gauges-instrument-panels/#interior-trim-except-cabriolet) or «INTERIOR TRIM - CABRIOLET»(/audi/a4/b6-2000-2006/remont/gauges-instrument-panels/#interior-trim-cabriolet) .
5. Loosen hex nuts -A- for central tube left side and unscrew approx. 15 mm. See «INTERIOR TRIM - EXCEPT CABRIOLET»(/audi/a4/b6-2000-2006/remont/gauges-instrument-panels/#interior-trim-except-cabriolet) or «INTERIOR TRIM - CABRIOLET»(/audi/a4/b6-2000-2006/remont/gauges-instrument-panels/#interior-trim-cabriolet) .
6. Remove hex nuts -B- for central tube on right side See «INTERIOR TRIM - EXCEPT CABRIOLET»(/audi/a4/b6-2000-2006/remont/gauges-instrument-panels/#interior-trim-except-cabriolet) or «INTERIOR TRIM - CABRIOLET»(/audi/a4/b6-2000-2006/remont/gauges-instrument-panels/#interior-trim-cabriolet) .
7. Remove connecting bolts between central tube and the windshield cross member (in passenger compartment). See «INTERIOR TRIM - EXCEPT CABRIOLET»(/audi/a4/b6-2000-2006/remont/gauges-instrument-panels/#interior-trim-except-cabriolet) or «INTERIOR TRIM - CABRIOLET»(/audi/a4/b6-2000-2006/remont/gauges-instrument-panels/#interior-trim-cabriolet) .
8. Remove connecting bolts between central tube and the plenum chamber (between electronic box and windshield cross member in plenum chamber). See «INTERIOR TRIM - EXCEPT CABRIOLET»(/audi/a4/b6-2000-2006/remont/gauges-instrument-panels/#interior-trim-except-cabriolet) or «INTERIOR TRIM - CABRIOLET»(/audi/a4/b6-2000-2006/remont/gauges-instrument-panels/#interior-trim-cabriolet) .
9. Pull central tube carefully back, until cross member touches the hex nuts on the left side and still rests on the threaded bolt on the right side.
10. Remove intermediate piece for defrost channel -A- and center air ducts for instrument panel -B-.
11. Remove evaporator drain from air conditioner unit. See «EVAPORATOR HOUSING DRAIN, REMOVING AND INSTALLING»(/audi/a4/b6-2000-2006/remont/automatic-hvac-system/#air-conditioning) .
12. Loosen securing ties of wiring harness on air conditioner unit
13. Remove passenger lower A-pillar trim and cut wire harness cable ties and move wire harness out of the way. See «INTERIOR TRIM - EXCEPT CABRIOLET»(/audi/a4/b6-2000-2006/remont/gauges-instrument-panels/#interior-trim-except-cabriolet) or «INTERIOR TRIM - CABRIOLET.»(/audi/a4/b6-2000-2006/remont/gauges-instrument-panels/#interior-trim-cabriolet)
14. Disconnect all electrical connection between wiring harness and the electrical components of the A/C system.

Note. The wiring harness "air conditioner" is removed together with the air conditioner unit.

1. Remove bolts -A-.
2. Remove air conditioner unit -A- toward passenger side.

Note. When removing air conditioner unit, make sure the two coolant lines of the heater core do not get caught or bend on plenum chamber or sound insulation mat. Observe wiring harness, individual wiring connection may get damaged when pulling on harness.

Installation is reverse of removal, noting the following

Note. Before installing, check all gaskets and seals on the air conditioner unit for damage and replace if necessary. Make sure coolant hoses to heater core are secured.

1. Connect coolant hoses properly to heater core. Observe markings

1. Supply hose from cylinder head
2. Return hose to water pump

Scheme 24

1. Install removed components, except storage compartment driver's side, in reverse order.
2. Bleed coolant circuit: See «COOLING SYSTEM, DRAINING AND FILLING»(/audi/a4/b6-2000-2006/remont/cooling-fan/#engine-cooling-18l-4-cyl-5v-turbo-amb) (1.8L Turbo), or «COOLANT, DRAINING AND REFILLING»(/audi/a4/b6-2000-2006/remont/cooling-fan/#engine-cooling-30l-6-cylinder-5v-avk) (3.0L V6), or «COOLING SYSTEM, DRAINING AND FILLING WITH COOLANT»(ref-229838-S12242823052006042100000) (4.2L V8).

Note. The heater core must additionally be bled, due to the allocation of the coolant lines to the heater core. Proceed as follows

Scheme 25

1. Bleed coolant circuit.
2. Switch ignition off.
3. Carefully open coolant reservoir cap (observe safety precautions when opening the cap) See «COOLING SYSTEM, DRAINING AND FILLING»(/audi/a4/b6-2000-2006/remont/cooling-fan/#engine-cooling-18l-4-cyl-5v-turbo-amb) (1.8L Turbo), or «COOLANT, DRAINING AND REFILLING»(/audi/a4/b6-2000-2006/remont/cooling-fan/#engine-cooling-30l-6-cylinder-5v-avk) (3.0L V6), or «COOLING SYSTEM, DRAINING AND FILLING WITH COOLANT»(ref-229838-S12242823052006042100000) (4.2L V8).
4. Loosen clamp on coolant hose -B-.
5. Pull hose -B- until the hole in the coolant hose is no longer sealed with the pipe.
6. Increase pressure in coolant circuit e.g. using V.A.G 1274 hand pump.
7. Bleed heater core via coolant hose -B- until coolant exits bubble free.
8. Push coolant hose -B- on heater core pipe and tighten with clamp.
9. Add coolant if necessary.
10. Check coolant circuit for leaks, pay particular attention between coolant hoses and heater core.
11. Install driver's side storage compartment and other removed components.
12. Install refrigerant lines from evaporator. See «REFRIGERANT LINES ON EVAPORATOR FLANGE, REMOVING AND INSTALLING»(/audi/a4/b6-2000-2006/remont/automatic-hvac-system/#air-conditioning) .
13. Check evaporator drain hose for correct seating. See «EVAPORATOR HOUSING DRAIN, CHECKING»(/audi/a4/b6-2000-2006/remont/automatic-hvac-system/#air-conditioning) .
14. Evacuate refrigerant circuit and recharge again. See «A/C REFRIGERANT SYSTEM (R-134A), DISCHARGING»(/audi/a4/b6-2000-2006/remont/automatic-hvac-system/#air-conditioning__ac-refrigerant-system-r-134a-discharging) .

Note. When installing the instrument panel, make sure that the intermediate piece for the defroster fits properly on the air conditioning unit and the defrost vent does not pinch the intermediate piece. After installing the instrument panel, check the vent direction and air distribution of flowing air coming from the defrost vent to windshield.

Evaporator, removing and installing

1. Remove air conditioner unit. See «HEATING AND A/C UNIT, REMOVING AND INSTALLING»(/audi/a4/b6-2000-2006/remont/automatic-hvac-system/#air-conditioning) .
2. Remove air conditioning wiring harness from air duct channel. See «HEATING ELEMENTS AND AIR DUCTS, REMOVING AND INSTALLING»(/audi/a4/b6-2000-2006/remont/automatic-hvac-system/#air-conditioning__heating-elements-and-air-ducts-removing) .
3. Remove bracket and protection cover for heater core coolant lines and remove heater core with coolant lines. See «HEATING ELEMENTS AND AIR DUCTS, REMOVING AND INSTALLING»(/audi/a4/b6-2000-2006/remont/automatic-hvac-system/#air-conditioning__heating-elements-and-air-ducts-removing)
4. Remove bracket for refrigerant lines and disconnect air duct channel from air distributor housing. See «HEATING AND A/C UNIT, DISASSEMBLING AND ASSEMBLING»(/audi/a4/b6-2000-2006/remont/automatic-hvac-system/#air-conditioning__heating-and-ac-unit-disassembling-and)
5. Disassemble air conditioner unit and remove evaporator from beneath out of air duct channel.

1. Before inserting the condenser, check evaporator drain and clean if necessary.
2. Mount sealing gasket -A- on evaporator -B-.
3. When inserting evaporator -B- into air duct -C-, make sure that sealing gasket -A- has not moved, if necessary lubricate sealing gasket -A- with soap water.
4. After assembling air duct -C- with air distributor housing, check at opening for refrigerant lines that the sealing gasket -A- is properly seated.
5. Removed evaporator contains refrigerant oil which must be restored to the refrigerant system.
6. Check the type of seal on connections and refrigerant lines, they must be designed for the same type of seal. See «CONNECTIONS OF REFRIGERANT LINES TO THE COMPONENTS (DIFFERENT VERSIONS)»(/audi/a4/b6-2000-2006/remont/automatic-hvac-system/#air-conditioning__connections-of-refrigerant-lines-to-the) and the Parts Catalog .

Using V.A.G 1551 Scan Tool (ST), check DTC memory for any electrical, vacuum or air distribution malfunctions, (see DIAGNOSTIC TROUBLE CODE (DTC) MEMORY, CHECKING (FUNCTION 02) ), correct/repair as necessary before proceeding.

1. There are no shut off requirements for the compressor; read measuring value block, display group 001, display field 1
2. Triggering and function of air flow flap and fresh air/recirculated air flap OK
3. All air ducts, seals and covers are OK

If one of the following conditions exists, follow recommended service

A/C does not cool (cooling has stopped completely)

1. Check refrigerant system pressures, see «A/C REFRIGERANT SYSTEM, CHECKING PRESSURES»(/audi/a4/b6-2000-2006/remont/automatic-hvac-system/#air-conditioning__ac-refrigerant-system-checking-pressures) .

Insufficient cooling during all driving or engine speed (RPM)

1. Check refrigerant system pressures. See «A/C REFRIGERANT SYSTEM, CHECKING PRESSURES»(/audi/a4/b6-2000-2006/remont/automatic-hvac-system/#air-conditioning__ac-refrigerant-system-checking-pressures) . Pressure switch -F129- shuts compressor off There is no outside air flow or air flow is severely restricted (evaporator iced up)

A/C compressor noisy

1. Tighten A/C compressor and compressor bracket mounting bolts using torque wrench. See «COMPRESSOR, REMOVING AND INSTALLING FROM BRACKET»(/audi/a4/b6-2000-2006/remont/automatic-hvac-system/#air-conditioning) .
2. Check routing of A/C refrigerant hoses and lines; hoses and lines must not contact other components and must be installed without binding; reposition or realign as necessary.

A/C compressor noisy immediately after switching A/C ON and/or when driving around corners or braking "refrigerant shock"- refrigerant system overcharged

1. Discharge refrigerant system. See «A/C REFRIGERANT SYSTEM (R-134A), DISCHARGING»(/audi/a4/b6-2000-2006/remont/automatic-hvac-system/#air-conditioning__ac-refrigerant-system-r-134a-discharging) . Evacuate and recharge, see «A/C REFRIGERANT SYSTEM (R-134A), EVACUATING AND RECHARGING»(/audi/a4/b6-2000-2006/remont/automatic-hvac-system/#air-conditioning__ac-refrigerant-system-r-134a-evacuating-and) .

With an otherwise properly operating A/C system, water sprays out of instrument panel vents

1. Check evaporator housing drain hose for proper routing (should not be kinked).
2. Check evaporator housing drain valve.

Note. Check evaporator drain plugs for correct installation (should not be pinched or bent). Check drain valves. They must not be plugged with wax, dirt or undercoating (clean if necessary). Valve flaps must close properly. Check air plenum cover (must be properly installed and not damaged).

A/C system, replacing components

1. The following replacement parts (compressor, accumulator, evaporator and compressor) are shipped charged with nitrogen gas. With time this charge drops, i.e. the pressure of the nitrogen charge is so small, that upon first opening gas may not escape.
2. All components of the refrigerant system which are being sent in for quality monitoring, should be closed (use original threaded assembly of replacement parts).

Note. Since in the replacement part process parts can be stored for a longer period of time and at various locations, it could happen that when first opened (even with parts of the same number) gas may or may not escape. Therefore, remove sealing caps carefully on connectors of parts and allow nitrogen gas to release slowly.

1. Close all open connectors and lines to prevent moisture penetration.
2. Replace restrictor.

For leaking or damaged components (except for compressor and accumulator), A/C system was completely empty (no charge)

1. Remove malfunctioning component.
2. Remove compressor.
3. Remove oil drain plug from compressor.

Note. Rotate compressor manually to speed up oil draining process. The compressor oil drain plug O-ring has been replaced with a sealing ring (always replace): See Parts department.

1. Drain old refrigerant oil out of compressor into a measuring container. Record volume of refrigerant oil drained.
2. Subsequently, fill compressor with new refrigerant oil equal to the amount of oil drained in previous step.

Note. Fill amounts for refrigerant oil, see REFRIGERANT (PAG) OIL, SYSTEM CAPACITY . To ensure adequate compressor lubrication, add at least 80 cm 3 (2.7 oz) of refrigerant oil into compressor, the remainder can be added to new accumulator. see REFRIGERANT (PAG) OIL, SYSTEM CAPACITY . If there is dirt in the compressor of an open A/C system (e.g. during an accident), replace compressor.

1. Blow through circuit with compressed air and nitrogen. see «A/C REFRIGERANT SYSTEM (R-134A), FLUSHING WITH COMPRESSED AIR AND NITROGEN»(/audi/a4/b6-2000-2006/remont/automatic-hvac-system/#air-conditioning__ac-refrigerant-system-r-134a-flushing-with) .
2. Replace accumulator and restrictor.
3. Assemble A/C system, evacuate and recharge. see «A/C REFRIGERANT SYSTEM (R-134A), EVACUATING AND RECHARGING»(/audi/a4/b6-2000-2006/remont/automatic-hvac-system/#air-conditioning__ac-refrigerant-system-r-134a-evacuating-and) .

For leaky or damaged components (except for the compressor and accumulator) there is still refrigerant in the A/C system

1. Discharge A/C system. see «A/C REFRIGERANT SYSTEM (R-134A), DISCHARGING»(/audi/a4/b6-2000-2006/remont/automatic-hvac-system/#air-conditioning__ac-refrigerant-system-r-134a-discharging) .
2. Remove malfunctioning component, blow through with compressed air, collect all exhausted oil in a measuring container. Refrigerant oil amount blown out of system, plus 20 cm 3 (0.7 oz) in evaporator, plus 10 cm 3 (0.3 oz) from condenser, refrigerant lines and hoses, is replaced as new refrigerant oil amount in the new component.
3. Replace restrictor.
4. Assemble A/C system, evacuate and recharge. see «A/C REFRIGERANT SYSTEM (R-134A), EVACUATING AND RECHARGING»(/audi/a4/b6-2000-2006/remont/automatic-hvac-system/#air-conditioning__ac-refrigerant-system-r-134a-evacuating-and) .

Replace compressor, without it being necessary to blow through the refrigerant system with compressed air and nitrogen (e.g. exterior damage after an accident)

1. Discharge A/C system. see «A/C REFRIGERANT SYSTEM (R-134A), DISCHARGING»(/audi/a4/b6-2000-2006/remont/automatic-hvac-system/#air-conditioning__ac-refrigerant-system-r-134a-discharging) .
2. Remove damaged compressor.
3. Remove oil drain plug from compressor.
4. Drain old refrigerant oil out of malfunctioning compressor into a measuring container. Record volume of drained refrigerant oil.

Note. Rotate compressor manually to speed up oil draining process. The compressor oil drain plug O-ring has been replaced with a sealing ring (always replace): See Parts department for proper part number or more assistance.

1. Drain refrigerant oil also out of replacement compressor into a clean container. Refill replacement compressor with amount of fresh oil equal to the amount poured out of malfunctioning compressor.

Example

From the malfunctioning compressor only 70 cm 3 (2.4 oz) of refrigerant oil was poured out. From the replacement compressor 220 cm 3 of refrigerant oil poured out (a small amount remains in compressor). 70 cm 3 (2.4 oz) of refrigerant oil needs to be poured back into replacement compressor (oil originally from replacement compressor, held in clean container).

Note. If a larger amount of refrigerant oil poured out of the malfunctioning compressor, more than approx. 80 cm 3 (2.7 oz) the remaining refrigerant oil can be used for the condenser or accumulator.

1. Replace restrictor.
2. Assemble A/C system, evacuate and recharge. see «A/C REFRIGERANT SYSTEM (R-134A), EVACUATING AND RECHARGING»(/audi/a4/b6-2000-2006/remont/automatic-hvac-system/#air-conditioning__ac-refrigerant-system-r-134a-evacuating-and) .

Replace compressor due to leaks or interior damage (e.g. noises or no power)

1. Discharge A/C system, see «A/C REFRIGERANT SYSTEM (R-134A), DISCHARGING»(/audi/a4/b6-2000-2006/remont/automatic-hvac-system/#air-conditioning__ac-refrigerant-system-r-134a-discharging) .
2. Remove compressor.

Note. If there is interior damage (to compressor), check refrigerant hoses. If there are chips embedded, replace hose.

1. Blow through A/C system with compressed air and nitrogen. See «A/C REFRIGERANT SYSTEM (R-134A), FLUSHING WITH COMPRESSED AIR AND NITROGEN»(/audi/a4/b6-2000-2006/remont/automatic-hvac-system/#air-conditioning__ac-refrigerant-system-r-134a-flushing-with) .
2. Replace accumulator and restrictor.
3. Assemble A/C system, evacuate and charge. see «A/C REFRIGERANT SYSTEM (R-134A), EVACUATING AND RECHARGING»(/audi/a4/b6-2000-2006/remont/automatic-hvac-system/#air-conditioning__ac-refrigerant-system-r-134a-evacuating-and) .

Replace accumulator and restrictor after blowing through the A/C system e.g. caused by penetrating moisture (the A/C system was open over a long period of time) or contamination (dirt)

1. Discharge A/C system. See «A/C REFRIGERANT SYSTEM (R-134A), DISCHARGING»(/audi/a4/b6-2000-2006/remont/automatic-hvac-system/#air-conditioning__ac-refrigerant-system-r-134a-discharging) .
2. Remove compressor.
3. Eliminate cause of malfunction.
4. Blow through A/C system with compressed air and nitrogen. See «A/C REFRIGERANT SYSTEM (R-134A), FLUSHING WITH COMPRESSED AIR AND NITROGEN»(/audi/a4/b6-2000-2006/remont/automatic-hvac-system/#air-conditioning__ac-refrigerant-system-r-134a-flushing-with) .
5. Remove oil drain plug out of compressor.
6. Drain old refrigerant oil out of compressor into measuring container.
7. Record volume of refrigerant oil drained.

Note. Rotate compressor manually to speed up oil draining process. The compressor oil drain plug O-ring has been replaced with a sealing ring (always replace): See Parts department.

1. Fill compressor with new refrigerant oil: the amount of oil must be equal to amount of old refrigerant oil drained.

Note. Fill amounts for refrigerant oil, see REFRIGERANT (PAG) OIL, SYSTEM CAPACITY . To ensure adequate compressor lubrication, add at least 80 cm 3 (2.7 oz) of refrigerant oil into compressor. The remainder can be added to new accumulator. See REFRIGERANT (PAG) OIL, SYSTEM CAPACITY . If there is dirt in the compressor of an open A/C system (e.g. during an accident), replace compressor.

1. Blow through A/C circuit with compressed air and nitrogen.
2. Replace accumulator and restrictor.
3. Assemble A/C system, evacuate and charge. See «A/C REFRIGERANT SYSTEM (R-134A), EVACUATING AND RECHARGING»(/audi/a4/b6-2000-2006/remont/automatic-hvac-system/#air-conditioning__ac-refrigerant-system-r-134a-evacuating-and) .

Replace accumulator, without it being necessary to blow through A/C system with compressed air and nitrogen (e.g. damage caused by an accident), no refrigerant flowed out and no moisture and dirt have penetrated the circuit

1. Discharge A/C system. See «A/C REFRIGERANT SYSTEM (R-134A), DISCHARGING»(/audi/a4/b6-2000-2006/remont/automatic-hvac-system/#air-conditioning__ac-refrigerant-system-r-134a-discharging) .
2. Replace restrictor.
3. Remove accumulator.
4. Clean accumulator.
5. Weigh removed accumulator.
6. Fill new accumulator with new refrigerant oil until it weighs as much as removed accumulator.
7. Install accumulator.
8. Assemble A/C system, evacuate and recharge. See «A/C REFRIGERANT SYSTEM (R-134A), EVACUATING AND RECHARGING»(/audi/a4/b6-2000-2006/remont/automatic-hvac-system/#air-conditioning__ac-refrigerant-system-r-134a-evacuating-and) .

See also:
• ACTIVATION FOR A/C COMPRESSOR REGULATOR VALVE -N280
• FRONT BUMPER
• FRONT BUMPER
• PRESSURE SIGNAL FROM HIGH PRESSURE SENSOR -G65
• NOISE INSULATION, ASSEMBLY OVERVIEW
• NOISE INSULATION, ASSEMBLY OVERVIEW
• LOCK CARRIER, MOVING TO SERVICE POSITION
• LOCK CARRIER, MOVING TO SERVICE POSITION
• ENGINE OIL, DRAINING OR EXTRACTING, CHANGE OIL FILTER
• DIAGNOSTIC TROUBLE CODE (DTC) MEMORY, CHECKING (FUNCTION 02)
• BASIC SETTING (FUNCTION 04)
• DIAGNOSTIC TROUBLE CODE (DTC) MEMORY, ERASING (FUNCTION 05)
• OUTPUT DIAGNOSTIC TEST MODE (DTM) (FUNCTION 03)
• INSTRUMENT PANEL
• INSTRUMENT PANEL
• DUST AND POLLEN FILTER, REPLACING
• WINDSHIELD DEFROSTER, FUNCTION
• WINDSHIELD DEFROSTER, DISABLING
• READ MEASURING VALUE BLOCK (FUNCTION 08)
• TEMPERATURE DEPENDING RESISTANCE VALUES OF SENSOR/SENDER
• A/C CONTROL HEAD -E87-, CODING (FUNCTION 07)
• INSTRUMENT PANEL, REMOVING AND INSTALLING
• INTERIOR EQUIPMENT - EXCEPT CABRIOLET
• RADIO SYSTEM - EXCEPT CABRIOLET
• RADIO SYSTEM - CABRIOLET
• GLOVE COMPARTMENT, REMOVING AND INSTALLING
• LOWER A-PILLAR TRIM, ASSEMBLY OVERVIEW
• LOWER A-PILLAR TRIM, ASSEMBLY OVERVIEW
• DISPLAY GROUP 014
• DISPLAY GROUP 018
• DRIVER-SIDE STORAGE COMPARTMENT (WITH AND WITHOUT KNEE BOLSTER), ASSEMBLY OVERVIEW
• EMERGENCY BATTERY, SWITCHING OFF/ON
• COOLING SYSTEM, DRAINING AND FILLING
• COOLANT, DRAINING AND REFILLING
• DISPLAY GROUP 010
• INTERPRETATION OF COMPRESSOR CUT-OFF CONDITION FOR DISPLAY FIELD 1 - 4
• HOOD CABLE, ASSEMBLY OVERVIEW
• REMOVING AND INSTALLING HOOD LOCK CABLE
• CHARGE AIR SYSTEM WITH TURBOCHARGER, SERVICING
• SECONDARY AIR SYSTEM
• A/C REFRIGERANT SYSTEM (R-134A), DISCHARGING
• WORK ON REFRIGERANT CIRCUIT
• DISCHARGE REFRIGERANT CIRCUIT
• A/C SYSTEM CONTROL AND REGULATION COMPONENTS
• A/C REFRIGERANT SYSTEM, SERVICING
• VEHICLES WITH 8 CYL. ENGINE (COMPRESSOR DRIVE VIA A SHAFT)
• COMPRESSOR DRIVE UNIT, CHECKING, REPLACING
• HIGH PRESSURE SENSOR -G65-, REMOVING AND INSTALLING
• O-RING SEALS FOR REFRIGERANT CIRCUIT
• REFRIGERANT LINES ON COMPRESSOR, REMOVING AND INSTALLING
• PULLEY, REMOVING FROM COMPRESSOR AND RE-INSTALLING (VERSION 1)
• COMPRESSOR DRIVE SHAFT, LOOSENING AND TIGHTENING
• RUN-OUT OF DRIVE PLATE WITH OVERLOAD PROTECTION, CHECKING AND ADJUSTING
• DRIVE PLATE WITH OVERLOAD PROTECTION, REMOVING AND INSTALLING
• DRIVE PLATE TO COMPRESSOR, REMOVING AND INSTALLING
• DRIVE PLATE WITH ROLLER BEARING, REMOVING AND INSTALLING
• DUST AND POLLEN FILTER ELEMENT, REMOVING AND INSTALLING
• DUST AND POLLEN FILTER WITH ACTIVE-CARBON-FILTER ELEMENT
• SENSOR FOR AIR QUALITY -G238-, REMOVING AND INSTALLING
• AIR EXTRACTION VENT, CHECKING
• ACTUATOR FOR TEMPERATURE FLAP LEFT -V158-, REMOVING AND INSTALLING
• LEFT FOOTWELL VENT TEMPERATURE SENSOR -G261-, REMOVING AND INSTALLING
• RIGHT FOOTWELL VENT TEMPERATURE SENSOR - G262-, REMOVING AND INSTALLING
• A/C CONTROL HEAD -E87-, REMOVING AND INSTALLING
• AIR GUIDE CONNECTION FOR GLOVE COMPARTMENT COOLING, REMOVING AND INSTALLING
• ACTUATOR FOR TEMPERATURE FLAP RIGHT -V159-, REMOVING AND INSTALLING
• HEATING AND A/C UNIT, COMPONENT OVERVIEW
• ADAPTER CABLE, MODIFYING TO ACTIVATE POSITIONING MOTORS
• COUPLING ELEMENT BETWEEN TEMPERATURE FLAPS "1" AND "2"
• IDENTIFYING MALFUNCTIONS IF SPECIFIED VALUES ARE NOT OBTAINED
• IDENTIFYING MALFUNCTIONS AT TEMPERATURE INCREASE BEHIND CONDENSER
• CHECK DTC MEMORY AND READ MEASURING VALUE BLOCK
• DID THE PRESSURE IN REFRIGERANT CIRCUIT (DISPLAY FIELD "4") INCREASE DURING COOLING PERFORMANCE TEST?
• CONTINUATION OF TEST - PRESSURE IN REFRIGERANT CIRCUIT INCREASES
• READ MEASURING VALUE BLOCK (FUNCTION 08), DISPLAY FIELD "4"
• CHECK ACTIVATION OF COOLANT FAN -V7
• CHECK ACTIVATION OF ACTUATOR FOR TEMPERATURE FLAP LEFT - V158
• CHECK SENSOR
• A/C REFRIGERANT SYSTEM (R-134A), EVACUATING AND RECHARGING
• SAFETY PRECAUTIONS
• DISCHARGING
• REFRIGERANT (PAG) OIL, SYSTEM CAPACITY
• A/C SYSTEM, REPLACING COMPONENTS
• A/C REFRIGERANT SYSTEM, CHECKING PRESSURES
• REFRIGERANT SYSTEM, SERVICING
• RESTRICTOR, REMOVING AND INSTALLING
• HEATING AND A/C UNIT, DISASSEMBLING AND ASSEMBLING
• CONNECTIONS OF REFRIGERANT LINES TO THE COMPONENTS (DIFFERENT VERSIONS)
• A/C SYSTEM, RUNNING AFTER INSTALLING COMPRESSOR
• HEATING ELEMENTS AND AIR DUCTS, REMOVING AND INSTALLING
• EVAPORATOR, REMOVING AND INSTALLING
• A/C REFRIGERANT SYSTEM (R-134A), FLUSHING WITH COMPRESSED AIR AND NITROGEN