Air Conditioning Audi S6 C5

A/C system, safety precautions

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

Empty (evacuate) refrigerant circuit first if the refrigerant circuit has to be opened during service. See A/C REFRIGERANT SYSTEM (R-134A), EVACUATING AND RECHARGING . The refrigerant must not come in contact with your skin. If refrigerant should escape although all safety precautions were observed, do not inhale refrigerant/air mixture.

The subassemblies and lines of the air conditioner are filled with

1.1.1.2 Tetrafluoroethane (CF 3 -CH 2 F or CH 2 F-CF 3 )

This refrigerant is currently known as R134a, H-FKW 134a, SUVA 134a and KLEA 134a (different names may apply to different countries.

1. Refrigerant R-134a replaces the refrigerant R-12 which is reported to have harmful effects on the earth's ozone layer.
2. 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.

Reason

If refrigerant R134a is released into the environment, it enhances the green house effect.

Note. Compared to R12, R134a 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 R12)

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.

If other body parts came in contact with refrigerant although all safety precautions were observed, flush body parts immediately for at least 15 minutes with cold water.

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

Reason

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

Drain refrigerant circuit

Climate control with refrigerant R134a

The refrigerant must be drained using an air conditioning service station and should not be released into the environment. The drained refrigerant will be locally recycled or is send to an environment-recycling place to the manufacturer (different or additional laws may apply in USA).

After draining the refrigerant circuit, interrupt the voltage supply to A/C Clutch -N25- or A/C Compressor Regulator Valve -N280-. For this, depending on vehicle equipment disconnect harness connector of A/C Pressure Switch -F129-/High Pressure Sensor -G65- or disconnect harness connector on compressor (to -N25-/to -N280-)

Reason

Disconnecting the voltage supply prevents accidental compressor operation via -N25- with the A/C system discharged.

The A/C Compressor Regulator Valve -N280- is not activated and the compressor runs at idle. This compressor is built in such 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 properly ventilated workshop. Ensure that within 5 meters circumference there are no working-pits, basement staircases or shafts. Switch on existing/ventilation systems when working on the refrigerant system.

Reason

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

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

Reason

Moisture enters the A/C system and components when system was opened for longer period of time. An A/C system that was 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.

Reason

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

Do not attempt repair on filled air conditioning systems by soldering, brazing or welding. This pertains also for welding and soldering work on the vehicle, in the event that parts of the climate control system may heat up

Reason

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

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.

A/C system, general repair guidelines

The refrigerant circuit of the A/C system must not be discharged and opened unless this is necessary because of safety precautions or unless components of the refrigerant circuit of the A/C system have to be to replaced. See A/C REFRIGERANT SYSTEM \(R-134A\), DISCHARGING .

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 REFRIGERANT CIRCUIT, SERVICING .

Note. The connections for switches mentioned in this Repair Manual are provided with a valve that closes automatically when the switches/sensors are unscrewed and removed. These switches can be replaced even though the refrigerant circuit is fully charged.

For servicing operations to A/C systems that require discharging the refrigerant circuits. See A/C REFRIGERANT SYSTEM (R-134A), DISCHARGING .

Service work on A/C systems that pertains to the refrigerant circuit should only be carried in workshops equipped with suitable workshop tools.

Commercial designation

Obtain R-134a refrigerant (tetrafluoroethane) from a local A/C supplier under one of the following names

1. H-FKW 134a
2. SUVA(R) 134a
3. KLEA 134a

Note. R-134a refrigerant is packaged in different containers. Use only R-134a that comes in containers having correct types of service fittings.

Color

Refrigerant R-134a is colorless and is invisible as a gas. Only the layer between the gas and the fluid is visible (fluid level in the tube of the cylinder or bubbles in the sight glass in the fluid reservoir). R-134a when viewed through a sight glass (if installed) may appear milky due to the mixing of refrigerant and lubricating oil (PAG oil).

Airborne properties

Escaped refrigerant gases are heavier than air and will gather first in low places, like under the car.

Solubility of refrigerant oil

A required special refrigerant oil Polyalkylene Glycol (PAG) synthetic oil is used to lubricate cylinder walls and bearings and enters the A/C system to some degree. This oil is NOT compatible with mineral based oils used in R-12 systems.

Note. R12 refrigerant systems use mineral oils which are not dissolved by R-134a refrigerant and are unusable.

Effects on the environment

Because R-134a does not contain chlorine atoms, the major catalyst in ozone depletion, R-134a has no ozone depletion potential.

R-134a does not cause smog and has a considerably lower global warming potential (greenhouse effect) than R-12 refrigerant. Nonetheless, do not release R-134a into the environment and always recover/recycle using approved service equipment.

Toxicity

Refrigerant R-134a is non-toxic up to a temperature of 101 ° C (214 ° F) and is safe when handled and used properly.

Above 101 ° C (214 ° F), gas pressure is above 39.5 bar (573 psi) and R-134a begins to decompose into poisonous gases (hydrogen fluoride, carbonyl fluoride and fluorine). These gases give adequate warning of their presence since they cause irritation of the mucous membrane (throat).

Refrigerant R-134a gas has no effect on foodstuffs; it does not poison food or make it inedible.

Temperature/pressure relationship

In a partially charged refrigerant container, refrigerant gas comes to the surface, which under particle formation becomes fluid. This occurs under pressure and is know as gas pressure. Similar to R-12 refrigerant, the gas pressure of R-134a is temperature dependent.

R134a TEMPERATURE/PRESSURE RELATIONSHIP

Effects on plastics

Refrigerant R-134a will deteriorate some plastics. When system temperature drops, these plastics can be deposited at the expansion valve or restrictor causing blockage. Therefore, when making system repairs, use only genuine Audi replacement parts which are specified for use with R-134a refrigerant.

Effects on metal

In its pure state, refrigerant R-134a is chemically stable and will not attack iron or aluminum. However, the mixture of R-134a and PAG oil may deteriorate certain metals (copper) which could lead to blockage, leaks or deposits on the compressor piston. Therefore, when making system repairs, use only genuine Audi replacement parts which are specified for use with R-134a refrigerant.

Critical temperature/critical pressure

R-134a refrigerant will remain chemically stable up to a pressure of 39.5 bar (573 psi). This corresponds to a temperature of 110 ° C (230 ° F). Above this temperature the refrigerant deteriorates. See CRITICAL TEMPERATURE/CRITICAL PRESSURE .

Water solubility

Liquid R-134a refrigerant will absorb only very minute quantities of moisture. However, R-134a vapor can absorb large amounts of moisture.

Water in the system forms ice in the expansion valve or restrictor causing the system to stop cooling. In addition, moisture combines with the refrigerant to form acids which will damage the system.

Flammability

R-134a refrigerant is not flammable. In fact, it tends to inhibit combustion and has a fire extinguishing effect. However, a flame or glowing hot surface, as well as ultraviolet light (from electric welding), will decompose the refrigerant into poisonous gases (hydrogen fluoride, carbonyl fluoride and fluorine). These gases give adequate warning of their presence since they cause irritation of the mucous membrane (throat).

R-134a can become flammable at pressures above ambient pressure in conjunction with air concentrations greater than 60% by volume.

Refrigerant containers

There must be pressure space available in the fluid area of the container. At increasing temperatures the fluid expands, the space filled with vapor becoming smaller. At a specific point there will only be fluid in the container. Beyond this point, only a slight increase in temperature will result in a very high pressure in the container.

Leak detection

Use halogen leak detectorHitec HI400A-TEL, or equivalent, to check for R-134a system leaks. This tool can also be used to detect leaks in R-12 systems. Many currently available R-12 leak detectors cannot detect R-134a refrigerant leaks.

A/C refrigerant oil (PAG), properties

A special Polyalkylene Glycol (PAG) synthetic oil is used in R-134a systems. This oil is NOT compatible with mineral based oils used in R-12 systems. See A/C SYSTEM, SAFETY PRECAUTIONS for Warnings and Cautions regarding proper oil usage.

Refrigerant system with restrictor and accumulator

1. Compressor
2. Condenser
3. Restrictor
4. Evaporator
5. Accumulator

Note. Arrows indicate direction of refrigerant flow.

Scheme 1

A/C compressor

Note. The manufacturer "Nippondenso" has changed its name to "Denso."

The compressor is driven via a ribbed belt on the engine when the A/C clutch engages (A/C ON).

Low pressure refrigerant gas from the evaporator is compressed by the compressor. After compression, the refrigerant gas (now high pressure) flows to the condenser.

The variable displacement A/C compressor varies piston stroke and output depending on load requirements and suction pressure.

Scheme 2

Note. The compressor contains PAG refrigerant oil that is mixable under all temperatures with refrigerant R-134a. A label on the compressor indicates that the compressor is for R-134a systems only.

A/C condenser

The condenser transfers heat from the compressed refrigerant gas to the outside air which causes the refrigerant to change state from a gas to a liquid.

Scheme 3

The restrictor (orifice tube) restricts and controls refrigerant flow to the evaporator thus lowering refrigerant temperature and pressure.

Upstream of the restrictor, the refrigerant is hot and under high pressure. Downstream of the restrictor, the refrigerant is cold and under low pressure.

A strainer located upstream of the restrictor filters out any dirt or particles. Another strainer located downstream of the restrictor atomizes the refrigerant before it enters the evaporator.

Scheme 4

Note. Insert the restrictor so that arrow -A- points to evaporator.

Evaporator

Liquid refrigerant entering the evaporator absorbs heat from air passing through the evaporator fins and cools the air. As the refrigerant absorbs heat it turns to vapor and is suctioned by the compressor.

Scheme 5

Accumulator

The accumulator traps the mixture of refrigerant vapor and gas coming from the evaporator. While in the accumulator, the refrigerant vapor turns to gas and, along with the refrigerant oil, is then suctioned by the compressor.

An oil extraction passage is incorporated into the accumulator to ensure that refrigerant oil flowing with the refrigerant does not remain in the accumulator.

Any moisture in the system is absorbed by the desiccant in the accumulator.

Scheme 6

O-rings

O-rings seal the connections between components of the A/C system.

Use only O-rings which are compatible with R-134a refrigerant and refrigerant (PAG) oil. Refer to the most recent parts information when obtaining new O-rings. O-rings are recognized by colors (currently red, green or violet).

Scheme 7

Note. Use O-rings only once and always replace. Handle the O-rings only in a clean working environment. Always use correct size O-rings (dimensions -a- and -b-). Lubricate the O-rings with refrigerant (PAG) oil before installing. Always make sure to properly install the O-rings on line/component mounting flanges/grooves. O-ring and torque specifications also apply to the threaded connections in the A/C lines.

Hoses and lines

The mixture of refrigerant oil (PAG oil) and refrigerant R-134a attacks some metals and alloys (for example, copper) and breaks down certain hose material. Use only hoses and lines which are identified with the lettering "R-134a."

Hoses and lines are secured with threaded connections. Always properly torque hose and line connections.

Pressure relief valve

The pressure relief valve is mounted on the compressor. At approx. 38 bar (551 psi), the valve opens to vent excessive pressure. When system pressure is reduced to approx. 30-35 bar (435-508 psi), the valve closes to prevent total refrigerant loss. The refrigerant will not discharge completely.

Scheme 8

A/C system, switches and valve connections

Note. Check shift pressures, switch and sensor removing and installing, as well as switch locations in A/C system. See REFRIGERANT CIRCUIT, SERVICING . There are several different versions of switch and sensor.

A/C pressure switch -F129

1. The compressor shuts off during a pressure drop in the A/C system (protects the compressor in an empty A/C system).
2. The compressor shuts off when there is excess pressure in the A/C system.
3. The coolant fan switches to second speed when pressure increases in A/C system.
4. For switch function, see «A/C PRESSURE SWITCH -F129»(/audi/s6/c5-1999-2004/remont/automatic-hvac-system/#air-conditioning) .

Scheme 9

Valve connection for pressure switch

A/C system pressure switches use different size threads than the service connection.

Use only these O-ring seals for connections. See O-RINGS .

1. Connection (lubricated)
2. O-ring seal
3. Valve

Scheme 10

A/C compressor speed sensor -G111

The A/C compressor no longer uses A/C compressor speed sensor -G111-.

A/C system, quick coupling connections

Note. Use only the specified quick coupling connectors resistant to R-134a and respective refrigerant oils. Connections for the high and low pressure sides have different outside diameters. Before removing the valve or valve stems, discharge refrigerant system. See A/C REFRIGERANT SYSTEM (R-134A), DISCHARGING . Always reinstall cap over service valve (with seal). Location in the A/C system, see REFRIGERANT CIRCUIT, SERVICING .

Connection with Schrader valve (example)

1. Service connection (lubricated)
2. Schrader valve stem
3. O-ring seal
4. Cap with seal

Scheme 11

A/C refrigerant system, pressure and temperature relationships

The pressures and temperatures in the A/C refrigerant system vary depending on engine speed (RPM), coolant fan speed 1 or 2, engine temperature, A/C compressor (ON/OFF), outside temperature, humidity, required cooling performance, etc.

Pressure and temperature specifications given in TABLE OF PRESSURE AND TEMPERATURE RELATIONSHIPS are based on the following

1. Engine running for approx. 20 minutes
2. Engine speed (RPM) 1500-2000
3. Outside (ambient) temperature 20 ° C (68 ° F)

With the engine not running and ambient temperature at 20 ° C (68°F) the pressure in the system should be approx. 4.7 bar (68 psi).

To check pressures, pressure testing equipment must be connected to the service valve. See REFRIGERANT CIRCUIT, SERVICING .

Scheme 12

A/C system with restrictor and accumulator, refrigerant flow

Note. Small arrows indicate the direction of refrigerant flow. Low side pressures are regulated and maintained within certain tolerances by the variable displacement compressor independent of engine speed (RPM). See A/C REFRIGERANT SYSTEM, CHECKING PRESSURES .

Note. The following list refers to items in (Scheme 12).

1. A/C compressor, high pressure side
2. A/C condenser
3. Restrictor
4. Evaporator
5. Accumulator
6. A/C compressor, low pressure side

Table of pressure and temperature relationships

Note. Component identification, see A/C SYSTEM WITH RESTRICTOR AND ACCUMULATOR, REFRIGERANT FLOW

Scheme 13

Refrigerant circuit, servicing

Note. All work or components marked with a 1) can be carried out or replaced without discharging the refrigerant circuit (work that does not pertain to refrigerant circuit). All refrigerant component circuits not marked with 1) as well as all coolant hoses and lines can only be serviced or replaced after discharging the refrigerant circuit. When installing refrigerant lines/hoses and pertaining bracket, make sure there is a sufficient gap between belt, bracket and belt pulley Up to model year 2001 only compressors with A/C Clutch -N25- are installed. From model year 2002 depending on engine type compressors with A/C Clutch -N25- or with A/C Compressor Regulator Valve -N280- are installed. See COMPRESSOR, WITH A/C CLUTCH -N25 and COMPRESSOR, WITH A/C COMPRESSOR REGULATOR VALVE -N280 . Servicing refrigerant system, see A/C REFRIGERANT SYSTEM, SERVICING .

Compressor, with A/C clutch -N25

Note. Starting September 1998, there was a running change in production from the version 1 air conditioner to the version 2 air conditioner. See AIR CONDITIONING CHANGES . Always observe safety measures in A/C SYSTEM, SAFETY PRECAUTIONS . A/C system components identified with an asterisk (*) may only be serviced or replaced after properly discharging refrigerant system. A/C system components not identified with an asterisk (*) can be serviced or replaced without discharging refrigerant system. Compressors supplied as replacement parts already contain the full quantity of refrigerant oil required for the A/C system (250 cm 3 ). A/C system cooling performance test, see A/C SYSTEM COOLING PERFORMANCE, TESTING . HP = High pressure side LP = Low pressure side Do not add refrigerant to the A/C system. Always discharge, evacuate and recharge system. See A/C REFRIGERANT SYSTEM (R-134A), DISCHARGING . The tightening torques and O-ring diameters given also apply to the threaded connections for the refrigerant lines between components. Install only O-rings that are approved for use with refrigerant R134a (currently color-coded red, light purple and dark purple). Checking pressures in the A/C system, see A/C REFRIGERANT SYSTEM, CHECKING PRESSURES .

1. Compressor * Compressor bracket removing and installing: - 6 Cyl.-gas engine, see «COMPRESSOR BRACKET, REMOVING AND INSTALLING (6 CYL. ENGINE, COMPRESSOR WITH A/C CLUTCH -N25-)»(/audi/s6/c5-1999-2004/remont/automatic-hvac-system/#air-conditioning__compressor-bracket-removing-and-installing-6) . "Denso" compressor to bracket, removing and installing 1) - 6 Cyl.-gas engine, see «COMPRESSOR BRACKET, REMOVING AND INSTALLING (6 CYL. ENGINE, COMPRESSOR WITH A/C CLUTCH -N25-)»(/audi/s6/c5-1999-2004/remont/automatic-hvac-system/#air-conditioning__compressor-bracket-removing-and-installing-6) . -8 Cyl.-Engine, see «DENSO COMPRESSOR, REMOVING AND INSTALLING FROM BRACKET (8 CYL. ENGINE WITH A/C CLUTCH - N25-)»(/audi/s6/c5-1999-2004/remont/automatic-hvac-system/#air-conditioning__denso-compressor-removing-and-installing-from) . Ribbed belt, removing and installing - 6 Cyl. - Gas engine See appropriate ENGINE MECHANICAL article. - 8 Cyl. engine See appropriate ENGINE MECHANICAL article. NOTE: Vehicles with 6 or 8 cylinder engines have "Denso" compressors installed. Mark running direction of ribbed belt before removing, reversed running direction may lead to belt damage. The compressor has a variable piston stroke which adjusts itself according to the cooling level required. CAUTION: If a new compressor has been installed or new refrigerant oil has been put into compressor (e.g. after blowing through A/C system and discharging compressor via oil drain plug), the compressor must be turned manually approx. 10 revolutions. This ensures that the compressor is not damaged when activated.
2. A/C clutch -N25- Service A/C clutch. 1) - "Denso" compressor, see «A/C CLUTCH -N25-, SERVICING (DENSO COMPRESSOR)»(/audi/s6/c5-1999-2004/remont/automatic-hvac-system/#air-conditioning__ac-clutch-n25-servicing-denso-compressor) . Check and adjust gap between belt and clutch pulley of A/C clutch 1) - "Denso" compressor, see «A/C CLUTCH -N25-, SERVICING (DENSO COMPRESSOR)»(/audi/s6/c5-1999-2004/remont/automatic-hvac-system/#air-conditioning__ac-clutch-n25-servicing-denso-compressor) .
3. Oil drain plug * Tightening torque: 30 Nm (22 ft lb) NOTE: The Denso compressor drain plug is installed with an ordinary sealing ring instead of an O-ring. This must always be replaced. Only remove the plug to drain the refrigerant oil.
4. High pressure relief valve * O-ring: 8.8 mm x 1.9 mm Tightening torque: 10 Nm (7ft lb) CAUTION: Connection -5- does not have a Schrader valve to prevent gas from escaping if the pressure relief valve is removed. Only remove the pressure relief valve when the refrigerant has been discharged from the A/C system.
5. Circuit with valve *
6. A/C Pressure Switch -F129-/High Pressure Switch -G65- A/C Pressure Switch -F129-, Function, removing and installing 1) , see «A/C PRESSURE SWITCH -F129»(/audi/s6/c5-1999-2004/remont/automatic-hvac-system/#air-conditioning) High Pressure Switch -G65-, removing and installing 1) , see «HIGH PRESSURE SENSOR -G65-, REMOVING AND INSTALLING»(/audi/s6/c5-1999-2004/remont/automatic-hvac-system/#air-conditioning__high-pressure-sensor-g65-removing-and) High Pressure Switch -G65-, checking signal 1) , see «TEST STEP 5: PRESSURE SIGNAL FROM HIGH PRESSURE SENSOR -G65»(/audi/s6/c5-1999-2004/remont/heated-glassdefoggers/#on-board-diagnostic-obd-hvac) . NOTE: A/C Pressure Switch -F129- were installed on vehicles up to model year 2001. On vehicles from model year 2002 High Pressure Sensor -G65- is installed.
7. Condenser * Removing and installing, see «CONDENSER, REMOVING AND INSTALLING»(/audi/s6/c5-1999-2004/remont/automatic-hvac-system/#air-conditioning) See «REFRIGERANT LINES FOR CONDENSER WITH BLOCK CONNECTION, REMOVING AND INSTALLING»(/audi/s6/c5-1999-2004/remont/automatic-hvac-system/#air-conditioning) . Different refrigerant R134a capacities depending on condenser type. See «A/C REFRIGERANT R-134A AND REFRIGERANT OIL (PAG), CAPACITIES»(/audi/s6/c5-1999-2004/remont/automatic-hvac-system/#air-conditioning) .
8. Connectors in refrigerant line * O-ring: 10.8 mm x 1.8 mm Tightening torque: 15 Nm (11 ft lb)
9. Closing cap 1) With seal, install Always re-install after using service valve
10. Service connection * High pressure side. For measuring, discharging and recharging
11. Restrictor * Installed in bolt position 8. Always replace restrictor (together with O-ring) O-ring: 7.5 mm x 1.5 mm Removing and installing, see «RESTRICTOR, REMOVING AND INSTALLING»(/audi/s6/c5-1999-2004/remont/automatic-hvac-system/#air-conditioning)
12. Evaporator * Disconnecting and connecting refrigerant lines, see «REFRIGERANT LINES ON EVAPORATOR, DISCONNECTING AND CONNECTING»(/audi/s6/c5-1999-2004/remont/automatic-hvac-system/#air-conditioning) Removing and installing air conditioner unit, see «COMPLETE AIR CONDITIONER UNIT, REMOVING AND INSTALLING»(/audi/s6/c5-1999-2004/remont/automatic-hvac-system/#air-conditioning__complete-air-conditioner-unit-removing-and) Disassembling and assembling air conditioner unit, see «A/C UNIT, DISASSEMBLING AND ASSEMBLING»(/audi/s6/c5-1999-2004/remont/automatic-hvac-system/#air-conditioning__ac-unit-disassembling-and-assembling) Two different versions: Version 2: width of evaporator is 32 mm less than in version 1 Version 1: evaporator can only be replaced together with air distributor housing
13. Service connection * Low pressure side
14. Closing cap 1) with seal, install Always re-install after using service valve
15. Catch reservoir (Accumulator) See «AIR CONDITIONING CHANGES»(/audi/s6/c5-1999-2004/remont/automatic-hvac-system/#air-conditioning) .

Compressor, with A/C compressor regulator valve -N280

Note. Starting September 1998, there was a running change in production from the version 1 air conditioner to the version 2 air conditioner. See AIR CONDITIONING CHANGES . Always observe safety measures. See A/C SYSTEM, SAFETY PRECAUTIONS . A/C system components identified with an asterisk (*) may only be serviced or replaced after properly discharging refrigerant system. A/C system components not identified with an asterisk (*) can be serviced or replaced without discharging refrigerant system. Compressors supplied as replacement parts already contain the full quantity of refrigerant oil required for the A/C system (250 cm 3 ). HP = High pressure side LP = Low pressure side A/C system cooling performance test. See A/C SYSTEM COOLING PERFORMANCE, TESTING . Do not add refrigerant to the A/C system. Always discharge, evacuate and recharge system. See A/C REFRIGERANT SYSTEM (R-134A), DISCHARGING . The tightening torques and O-ring diameters given also apply to the threaded connections for the refrigerant lines between components. Install only O-rings that are approved for use with refrigerant R134a (currently color-coded red, light purple and dark purple). Checking pressures in the A/C system. See A/C REFRIGERANT SYSTEM, CHECKING PRESSURES .

1. A/C Compressor Regulator Valve -N280- Checking activation and function 1) , see «TEST STEP 6: ACTIVATION FOR A/C COMPRESSOR REGULATOR VALVE -N280»(/audi/s6/c5-1999-2004/remont/heated-glassdefoggers/#on-board-diagnostic-obd-hvac__test-step-6-activation-for-ac)
2. Compressor * Compressor to bracket, removing and installing 1) , see «COMPRESSOR WITH A/C COMPRESSOR REGULATOR VALVE -N280-, REMOVING AND INSTALLING FROM BRACKET»(/audi/s6/c5-1999-2004/remont/automatic-hvac-system/#air-conditioning) When installing refrigerant lines/hoses and pertaining bracket, make sure there is a sufficient gap between belt, bracket and belt pulley Compressor type varies depending on engine (installed on right or left side of engine, 6 cylinder engine gas engine
3. Compressor belt pulley/drive unit Replacing belt pulley, see «COMPRESSOR BELT PULLEY/ DRIVE UNIT, REPLACING (COMPRESSOR WITHOUT A/C CLUTCH)»(/audi/s6/c5-1999-2004/remont/automatic-hvac-system/#air-conditioning) Ribbed belt, removing-and installing: See appropriate ENGINE MECHANICAL article. Ribbed belt-allocation: Checking, replacing compressor drive unit, see «COMPRESSOR BELT PULLEY/ DRIVE UNIT, REPLACING (COMPRESSOR WITHOUT A/C CLUTCH)»(/audi/s6/c5-1999-2004/remont/automatic-hvac-system/#air-conditioning) NOTE: A rubber element is installed between the belt pulley and drive shaft of compressor, this protects the belt 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. Vibrations which may occur during compressor operation can be eliminated via the rubber element (dampening function during torque fluctuations).
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/s6/c5-1999-2004/remont/automatic-hvac-system/#air-conditioning__high-pressure-sensor-g65-removing-and) Checking signal, see «TEST STEP 5: PRESSURE SIGNAL FROM HIGH PRESSURE SENSOR -G65»(/audi/s6/c5-1999-2004/remont/heated-glassdefoggers/#on-board-diagnostic-obd-hvac)
8. Condenser *
9. Closing cap with seal Always install
10. Service connection * High pressure side to measure, discharge and charge refrigerant circuit
11. Connectors in refrigerant line *
12. Restrictor * Installed in connector position 11.
13. Evaporator *
14. Service connection * Low pressure side To measure and discharge refrigerant circuit
15. Closing cap With seal Always install
16. Catch reservoir (Accumulator) *

A/C clutch -N25-, servicing (Denso compressor)

Note. The manufacturer "Nippondenso" has changed its name to "Denso."

Note. In order to service A/C clutch, remove compressor from clutch (do not open refrigerant circuit). Ribbed belt, removing and installing. - 6 and 8 cyl. engine See appropriate ENGINE MECHANICAL article. Before removing mark direction of rotation of ribbed belt using chalk or felt-tip marker.

Scheme 14

1. Bolt Tightening torque 15 Nm. Loosen and tighten, see «LOOSEN AND TIGHTEN HEX BOLT»(/audi/s6/c5-1999-2004/remont/automatic-hvac-system/#air-conditioning__loosen-and-tighten-hex-bolt) .
2. Clutch disc Remove (pull off), see «REMOVING CLUTCH PLATE»(/audi/s6/c5-1999-2004/remont/automatic-hvac-system/#air-conditioning__removing-clutch-plate)
3. Spacing discs For adjusting gap between clutch plate and belt pulley. Gap: 0.4 to 0.6 mm Checking and adjusting gap, see «CHECKING AND ADJUSTING GAP»(/audi/s6/c5-1999-2004/remont/automatic-hvac-system/#air-conditioning)
4. Snap ring Always replace Must be correctly installed (flat side toward compressor). Must be properly seated in groove.
5. Belt pulley NOTE: If the belt pulley is installed too tightly, use a commercially available two-arm or three arm puller to remove the belt pulley.
6. Snap ring Always replace Must be correctly installed (flat side toward compressor). Must be properly seated in groove.
7. Magnetic coil Removing, see «INSTALLING MAGNETIC COIL»(/audi/s6/c5-1999-2004/remont/automatic-hvac-system/#air-conditioning__installing-magnetic-coil) NOTE: In the magnetic coil is a thermo fuse installed. The thermo fuse interrupts the operation of the coil if it becomes too hot (e.g. if the compressor is not moving freely). The Protection Diode -J201- is installed in this magnet coil (suppresses voltage peaks which may occur when A/C clutch is switched off).
8. Bolt
9. Compressor (Denso)

Loosen and tighten hex bolt

1. Tightening torque 15 Nm.

Scheme 15

Note. Use commercially available strap wrench -A- (with fabric strap for counterholding the clutch plate).

Removing clutch plate

1. Pry off carefully using screw driver.

Scheme 16

Note. If the clutch pulley is installed too tightly, use a commercially available two-arm or three arm puller.

Installing magnetic coil

1. Locate tab -A- in recess -B-.

Scheme 17

Scheme 18

1. Measure distance "1" between belt pulley and clutch pulley using depth gauge -C- (at three different points).
2. Apply 12 V to magnetic coil (B+ terminal to single-pin connector -A-, Ground (GND) to compressor housing -B-).
3. Measure distance "2" between belt pulley and clutch pulley using depth gauge -C-.
4. Gap width (difference between distance "1" and "2"): 0.4 to 0.6 mm

Scheme 19

Note. The gap width must be within the tolerance around the whole circumference. The gap width can also be measured without removing the compressor (compressor installed). If the gap width is outside the specified tolerance, remove the clutch plate and adjust the gap width by removing or adding shims.

High pressure sensor -G65-, removing and installing

1. Remove front bumper: See «BUMPER»(/audi/s6/c5-1999-2004/remont/exterior-body-panels/#bumper) .
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/s6/c5-1999-2004/remont/automatic-hvac-system/#air-conditioning__o-ring-seals-for-refrigerant-circuit) .

Note. The illustration shows High Pressure Sensor -G65- on condenser for vehicle with 2.0L or 3.0L gas engine, on other condensers the High Pressure Sensor -G65- is installed on the right hand side. 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 STEP 5: PRESSURE SIGNAL FROM HIGH PRESSURE SENSOR -G65 .

Scheme 20

1. At low or high pressure in the refrigerant circuit the low/high pressure switch (switch between terminals 1 and 2) switches the compressor off (via A/C Control Head -E87-). Switching pressures (in bar high pressure): Switch open (compressor off): Low pressure switch (opens at 1.2 bar and closes at 1.8 bar). High pressure switch (opens at 30 bar and closes at 14.5 bar). Switch closed (compressor on): 1.2 (1.8) bar to 30 (14.5) bar.
2. Coolant Fan -V7- is switched to second speed via the high pressure switch (switch between contact 3 and 4). Switching pressures (in bar high pressure): Second speed of coolant fan engages at 16 bar (switch closes). Second speed of coolant fan is switched off at 12.5 bar (switch opens).

Scheme 21

1. Remove front bumper See «BUMPER»(/audi/s6/c5-1999-2004/remont/exterior-body-panels/#bumper) .
2. Disconnect harness connector.
3. Remove pressure switch -B-: 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/s6/c5-1999-2004/remont/automatic-hvac-system/#air-conditioning__o-ring-seals-for-refrigerant-circuit) .

Notes

1. With the switch removed bridge terminals 1 and 2 of connector -B- to check cooling performance.
2. The refrigerant circuit remains closed, connection with valve.

Check function

1. Start engine
2. Compressor switched on (operating mode "Auto" on A/C control head adjusted).

Scheme 22

1. Compressor should run: Disconnect harness connector -B- from switch Compressor off (low pressure switch open). Remove switch -A- and connect connector -B-. Compressor is not switched on (low pressure switch open).
2. Compressor not running: Disconnect harness connector -B- from switch -A- and bridge terminals 1 and 2 on connector -B-: Compressor is switched on. NOTE: If the compressor is switched on when bridging the connector, the switch is faulty or there is not enough pressure in the refrigerant system (refrigerant system empty). In order to check pressures in A/C system send vehicle to an authorized VW/Audi A/C workshop. If the compressor is not switched on and A/C Pressure Switch -F129- is displayed in measuring value block for compressor cut-off condition, locate and eliminate open circuit in wiring connection between A/C Pressure Switch -F129- and A/C Control Head -E87-. See «AIR CONDITIONING, ELECTRICAL TESTING»(/audi/s6/c5-1999-2004/remont/heated-glassdefoggers/#on-board-diagnostic-obd-hvac) . On vehicles from model year 2002 High Pressure Sensor -G65- is installed instead of A/C Pressure Switch -F129-. See «HIGH PRESSURE SENSOR -G65-, REMOVING AND INSTALLING»(/audi/s6/c5-1999-2004/remont/automatic-hvac-system/#air-conditioning__high-pressure-sensor-g65-removing-and) .

O-ring seals for refrigerant circuit

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

Note. Use only O-rings that are resistant to refrigerant R134a and refrigerant oil. These O-rings are color-coded to avoid confusion (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. Dimensions -a- and -b- vary depending on the installation location of O-ring.

Scheme 23

A/C system components (in engine compartment)

Note. After completing service work, always check and erase DTC memory, carry out basic setting and check coding of A/C control head -E87-. Check cooling performance, see A/C SYSTEM COOLING PERFORMANCE, TESTING . Service work on refrigerant circuit, see REFRIGERANT CIRCUIT, SERVICING . Components marked with * will be activated during the OUTPUT DIAGNOSTIC TEST MODE (DTM) . Observe different codings of A/C Control Head -E87-. See A/C CONTROL HEAD -E87-, CODING . Electrical testing is possible on all components marked with **. See AIR CONDITIONING, ELECTRICAL TESTING .

Note. Items 1 through 14 in the following list (Scheme 27)

Scheme 24

1. Air extraction vent Sealing flaps on air extraction vent must be able to move freely and close automatically (checking, see «AIR EXTRACTION VENT, CHECKING»(/audi/s6/c5-1999-2004/remont/automatic-hvac-system/#air-conditioning__air-extraction-vent-checking) ). NOTE: For vehicle interior ventilation to work properly, air ducts which run through the luggage compartment trim and lead to the two air extraction vents (under the bumper on the left and right side) must not be unobstructed.
2. Compressor (with A/C Clutch -N25-) WARNING: Before removing ribbed belt, mark the running direction. The belt could break if it is run in the reverse direction. Only remove the compressor when the refrigerant has been discharged from the A/C system. NOTE: The following procedures for working on the compressor are different depending on the engine and compressor type: Removing and installing ribbed belt, Removing and installing compressor from bracket, and Removing and installing compressor bracket. See «REFRIGERANT CIRCUIT, SERVICING»(/audi/s6/c5-1999-2004/remont/automatic-hvac-system/#air-conditioning__refrigerant-circuit-servicing) as well as: Appropriate ENGINE MECHANICAL article. The compressor is installed on the right or left side of the engine depending on engine type. Up to model year 2001 only compressors with A/C Clutch -N25- are installed. From model year 2002 depending on engine type, compressors with A/C Clutch -N25- or with A/C Compressor Regulator Valve -N280- are installed. See «COMPRESSOR, WITH A/C CLUTCH -N25»(/audi/s6/c5-1999-2004/remont/automatic-hvac-system/#air-conditioning__compressor-with-ac-clutch-n25) and «COMPRESSOR, WITH A/C COMPRESSOR REGULATOR VALVE -N280»(/audi/s6/c5-1999-2004/remont/automatic-hvac-system/#air-conditioning__compressor-with-ac-compressor-regulator-valve).
3. A/C clutch -N25-* NOTE: Up to model year 2001 only compressors with A/C Clutch -N25- are installed. From model year 2002 depending on engine type, compressors with A/C Clutch -N25- or with A/C Compressor Regulator Valve -N280- are installed. See «COMPRESSOR, WITH A/C CLUTCH -N25»(/audi/s6/c5-1999-2004/remont/automatic-hvac-system/#air-conditioning__compressor-with-ac-clutch-n25) and «COMPRESSOR, WITH A/C COMPRESSOR REGULATOR VALVE -N280»(/audi/s6/c5-1999-2004/remont/automatic-hvac-system/#air-conditioning__compressor-with-ac-compressor-regulator-valve). Service A/C clutch -N25-. "Denso"-compresso, see «A/C CLUTCH -N25-, SERVICING (DENSO COMPRESSOR)»(/audi/s6/c5-1999-2004/remont/automatic-hvac-system/#air-conditioning__ac-clutch-n25-servicing-denso-compressor). Check and adjust width of gap between belt and clutch pulley of A/C clutch. - "Denso"-compressor, see «A/C CLUTCH -N25-, SERVICING (DENSO COMPRESSOR)»(/audi/s6/c5-1999-2004/remont/automatic-hvac-system/#air-conditioning__ac-clutch-n25-servicing-denso-compressor).
4. Condenser WARNING: Only remove the condenser when the refrigerant has been discharged from the A/C system.
5. Outside air temperature sensor -G17-** Removing and installing: Unclip sensor from retainer in bumper. Remove bumper (only on Outside Air Temperature Sensor -G17- with harness connector not directly on -G17-). See «BUMPER»(/audi/s6/c5-1999-2004/remont/exterior-body-panels/#bumper) and «LOCK CARRIER, SERVICE POSITION»(/audi/s6/c5-1999-2004/remont/exterior-body-panels/#body-front__lock-carrier-service-position). Disconnect harness connector.
6. A/C Pressure Switch - F129-**/High Pressure Switch -G65-** A/C Pressure Switch -F129-, Function, removing and installing, see «A/C PRESSURE SWITCH -F129»(/audi/s6/c5-1999-2004/remont/automatic-hvac-system/#air-conditioning) High Pressure Sensor -G65-, Function, removing and installing, see «HIGH PRESSURE SENSOR -G65-, REMOVING AND INSTALLING»(/audi/s6/c5-1999-2004/remont/automatic-hvac-system/#air-conditioning__high-pressure-sensor-g65-removing-and) The measuring value of High Pressure Sensor G65- is displayed in function "Read Measuring Value Block" by A/C Control Head -E87-. See «DISPLAY GROUP 001: A/C COMPRESSOR REGULATOR VALVE -N280-, A/C CLUTCH RELAY -J44- AND HIGH PRESSURE SENSOR -G65»(/audi/s6/c5-1999-2004/remont/heated-glassdefoggers/#on-board-diagnostic-obd-hvac) and «TEST STEP 5: PRESSURE SIGNAL FROM HIGH PRESSURE SENSOR -G65»(/audi/s6/c5-1999-2004/remont/heated-glassdefoggers/#on-board-diagnostic-obd-hvac). Installation location on all vehicles except 2.0 L and 3.0 L gas engine NOTE: Up to model year 2001 the A/C Pressure Switch -F129- has been installed, on vehicles from model year 2002 the A/C Pressure Switch -F129- has been replaced by the High Pressure Sensor -G65- (different version of A/C Control Head -E87-). The A/C Pressure Switch -F129-/High Pressure Sensor -G65- can also be installed on the left hand side of the condenser, depending on condenser version.
7. Catch reservoir (Accumulator) WARNING: Only remove the accumulator when the refrigerant has been discharged from the A/C system.
8. Evaporator housing drain valve Checking, removing and installing, see «EVAPORATOR HOUSING DRAIN VALVE, CHECKING, REMOVING AND INSTALLING»(/audi/s6/c5-1999-2004/remont/automatic-hvac-system/#air-conditioning__evaporator-housing-drain-valve-checking-removing).
9. Restrictor Installed in refrigerant line WARNING: Only open the screw connection when the refrigerant has been discharged from the A/C system.
10. Service connection High pressure side For measuring pressures, discharging and charging the refrigerant circuit. NOTE: A cap with seal must always be installed on the service valves.
11. Service connection Low pressure side For measuring pressures and discharging the refrigerant circuit. NOTE: A cap with seal must always be installed on the service valves.
12. Dust and pollen filter Removing and installing, see «DUST AND POLLEN FILTER ELEMENT, REMOVING AND INSTALLING»(/audi/s6/c5-1999-2004/remont/automatic-hvac-system/#air-conditioning__dust-and-pollen-filter-element-removing). Follow filter change intervals Different versions (with or without active carbon filter element, see «DUST AND POLLEN FILTER WITH ACTIVE CARBON FILTER ELEMENT»(/audi/s6/c5-1999-2004/remont/automatic-hvac-system/#air-conditioning__dust-and-pollen-filter-with-active) )
13. Air flow flap Air flow flap motor -V71-* with back pressure flap motor position sensor -G113-, removing and installing, see «CENTRAL AIR FLAP MOTOR -V70-, REMOVING AND INSTALLING»(/audi/s6/c5-1999-2004/remont/automatic-hvac-system/#air-conditioning__central-air-flap-motor-v70-removing). On vehicles up to model year 2001, the Air Flow Flap Motor -V71- moves the back pressure flap as well as the fresh air and air recirculation flap (back pressure flap remains closed during recirculation mode).
14. Air recirculation/fresh air flap On vehicles up to model year 2001 actuated together with back pressure flap by Air Flow Flap Motor -V71-. Up to model year 2001 the air recirculation/fresh air flap is actuated by Recirculation Flap Motor-V113-. See Read measuring value block «DISPLAY GROUP 007: RECIRCULATION FLAP MOTOR -V113»(/audi/s6/c5-1999-2004/remont/heated-glassdefoggers/#on-board-diagnostic-obd-hvac) and «DISPLAY GROUP 008: AIR FLOW FLAP MOTOR -V71»(/audi/s6/c5-1999-2004/remont/heated-glassdefoggers/#on-board-diagnostic-obd-hvac). NOTE: Items 15 through 20 in the following list (Scheme 28)
15. Sunroof with solar cells Checking function, see «SOLAR SUNROOF, ELECTRICAL TESTING»(/audi/s6/c5-1999-2004/remont/heated-glassdefoggers/#on-board-diagnostic-obd-hvac) Removing and installing See «SUNROOF»(/audi/s6/c5-1999-2004/remont/sun-rooft-topconvertible-top/#sunroof).
16. Sensor for air quality -G238- Function, see «SENSOR FOR AIR QUALITY -G238-, FUNCTION»(/audi/s6/c5-1999-2004/remont/heated-glassdefoggers/#on-board-diagnostic-obd-hvac__sensor-for-air-quality-g238-function) Checking, see «SENSOR FOR AIR QUALITY -G238-, CHECKING»(/audi/s6/c5-1999-2004/remont/heated-glassdefoggers/#on-board-diagnostic-obd-hvac) Removing and installing, see «SENSOR FOR AIR QUALITY -G238-, REMOVING AND INSTALLING»(/audi/s6/c5-1999-2004/remont/automatic-hvac-system/#air-conditioning__sensor-for-air-quality-g238-removing) NOTE: Sensor for air quality -G238- is installed in vehicles starting with model year 2002 (different version of A/C control head -E87-).
17. Coolant FC (Fan Control) Control Module -J293- * Only installed on vehicles starting with model year 2002 and 2.0 L and 3.0 L engine NOTE: The activation method for the coolant fan depends on model year and engine type. Activation method of coolant fan on vehicles from model year 2002: See Read measuring value block, «DISPLAY GROUP 014: COOLANT FAN -V7- ACTIVATION»(/audi/s6/c5-1999-2004/remont/heated-glassdefoggers/#on-board-diagnostic-obd-hvac) and ON-BOARD DIAGNOSTIC (OBD).
18. High Pressure Sensor -G65- Function, removing and installing, see «HIGH PRESSURE SENSOR -G65-, REMOVING AND INSTALLING»(/audi/s6/c5-1999-2004/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 «DISPLAY GROUP 001: A/C COMPRESSOR REGULATOR VALVE -N280-, A/C CLUTCH RELAY -J44- AND HIGH PRESSURE SENSOR -G65»(/audi/s6/c5-1999-2004/remont/heated-glassdefoggers/#on-board-diagnostic-obd-hvac). Installation location on all vehicles with 2.0 L and 3.0 L gas engine NOTE: On vehicles from model year 2002 High Pressure Sensor -G65- is installed instead of A/C Pressure Switch -F129- (changed version of A/C control head -E87-) The High Pressure Sensor -G65- can also be installed on the right hand side of the condenser, depending on condenser version.
19. Compressor (with A/C Compressor Regulator Valve -N280-) Replacing belt pulley, see «COMPRESSOR BELT PULLEY/ DRIVE UNIT, REPLACING (COMPRESSOR WITHOUT A/C CLUTCH)»(/audi/s6/c5-1999-2004/remont/automatic-hvac-system/#air-conditioning) Checking, replacing compressor drive unit, see «COMPRESSOR BELT PULLEY/ DRIVE UNIT, REPLACING (COMPRESSOR WITHOUT A/C CLUTCH)»(/audi/s6/c5-1999-2004/remont/automatic-hvac-system/#air-conditioning) WARNING: Only remove the compressor when the refrigerant has been discharged from the A/C system. NOTE: The following procedures for working on the compressor are different depending on the engine and compressor type: Removing and installing ribbed belt, Removing and installing compressor from bracket. and Removing and installing compressor bracket. See «REFRIGERANT CIRCUIT, SERVICING»(/audi/s6/c5-1999-2004/remont/automatic-hvac-system/#air-conditioning__refrigerant-circuit-servicing) as well as: Appropriate ENGINE MECHANICAL article. The compressor is installed on the right or left side of the engine depending on engine type. Up to model year 2001 only compressors with A/C Clutch -N25- were installed. As of model year 2002 depending on engine type, compressors with A/C Clutch -N25- or with A/C Compressor Regulator Valve -N280- are installed. See «COMPRESSOR, WITH A/C CLUTCH -N25»(/audi/s6/c5-1999-2004/remont/automatic-hvac-system/#air-conditioning__compressor-with-ac-clutch-n25) and «COMPRESSOR, WITH A/C COMPRESSOR REGULATOR VALVE -N280»(/audi/s6/c5-1999-2004/remont/automatic-hvac-system/#air-conditioning__compressor-with-ac-compressor-regulator-valve).
20. A/C Compressor Regulator Valve -N280- * Checking activation and function, see «TEST STEP 6: ACTIVATION FOR A/C COMPRESSOR REGULATOR VALVE -N280»(/audi/s6/c5-1999-2004/remont/heated-glassdefoggers/#on-board-diagnostic-obd-hvac__test-step-6-activation-for-ac)

Scheme 25

Note. Up to model year 2001 only compressors with A/C Clutch -N25- are installed. From model year 2002 depending on engine type, compressors with A/C Clutch -N25- or with A/C Compressor Regulator Valve -N280- are installed. See COMPRESSOR, WITH A/C CLUTCH -N25 and COMPRESSOR, WITH A/C COMPRESSOR REGULATOR VALVE -N280 .

Evaporator housing drain valve, checking, removing and installing

1. Evaporator housing drain valve -A- must not be clogged and must close freely. The drainage hole must be at the bottom.

Scheme 26

Note. Remove evaporator housing drain valve from floor panel -B- in downward direction. When installed, the evaporator housing drain valve must not be touching the heat shield. The evaporator drain valve must not be clogged with wax or undercoating. When installing, position correctly in floor panel -B-. Drainage duct -A- is bolted to the floor panel with bolts -B- and must not interfere with the operation of the evaporator housing drain valve. (Scheme 30) If the customer reports moisture in the vehicle interior, check and if necessary clean condensation drainage system and valve. Also check the operation of the two forced air extraction vents in the luggage compartment. See AIR EXTRACTION VENT, CHECKING. Foam sealing pad -A- must lie flush against the drainage duct. (Scheme 31) The drainage duct and foam sealing pad can only be replaced when the air conditioner unit has been removed. See COMPLETE AIR CONDITIONER UNIT, REMOVING AND INSTALLING. The condensation drainage duct has a drip lobe -B- which prevents condensation on the duct from seeping back into the foam sealing pad. (Scheme 31) If the drip lobe has broken off, install spout -A- (Part No. 8D0 860 155) as shown in illustration and seal it todrainage duct with silicone sealant adhesive.

1. If passenger compartment is moist: Check air extraction outlets in passenger compartment (via luggage compartment). See «AIR EXTRACTION VENT, CHECKING»(/audi/s6/c5-1999-2004/remont/automatic-hvac-system/#air-conditioning__air-extraction-vent-checking) . For vehicles as of model year 2002, check the signal for detection of windshield wiper operation at A/C Control Head -E87-. See Read measuring value block, «DISPLAY GROUP 017: MEASURING VALUES FOR SUNLIGHT PHOTO SENSOR -G107-, SIGNAL FROM WINDSHIELD WIPER SWITCH FOR WASHER PUMP AND WINDSHIELD WIPER»(/audi/s6/c5-1999-2004/remont/heated-glassdefoggers/#on-board-diagnostic-obd-hvac__display-group-017-measuring-values-for) . Check dust and pollen filter for soiling and the cover for correct installation. See «DUST AND POLLEN FILTER ELEMENT, REMOVING AND INSTALLING»(/audi/s6/c5-1999-2004/remont/automatic-hvac-system/#air-conditioning__dust-and-pollen-filter-element-removing) Check various positioning motors and the pertaining levers, pay particular attention to position of Air Flow Flap Motor -V71- and Recirculation Flap Motor -V113- and the pertaining flaps For vehicles as of model year 2002 and a compressor with A/C Compressor Regulator Valve -N280-, check measured value of Evaporator Vent Temperature Sensor -G263-. See Read measuring value blocks, «DISPLAY GROUP 010: MEASURING VALUES FOR EVAPORATOR VENT TEMPERATURE SENSOR -G263-, FRESH AIR INTAKE DUCT TEMPERATURE SENSOR -G89-, OUTSIDE AIR TEMPERATURE SENSOR -G17- AND CALCULATED OUTSIDE TEMPERATURE TRANSMITTED TO INSTRUMENT CLUSTER»(/audi/s6/c5-1999-2004/remont/heated-glassdefoggers/#on-board-diagnostic-obd-hvac) . If measured value of the sensor is too low under operating conditions specified by customer (at an ambient temperature above 0 ° C,colder than 0 ° C for a long period of time), observe notes for testing cooling performance. See «A/C SYSTEM COOLING PERFORMANCE, TESTING»(/audi/s6/c5-1999-2004/remont/automatic-hvac-system/#air-conditioning__ac-system-cooling-performance-testing) . In vehicles without Evaporator Vent Temperature Sensor -G263-, check vent temperature of air from evaporator e.g. via Sender for outlet temperature, floor outlet -G192- at the adjustment: "Temperature Lo" for driver's- and passenger side, 4 or 5 bars for fresh air blower RPM, air outlet in footwell and fresh air operation under operating conditions specified by customer. If measured value of the sensor is too low (at an ambient temperature above 0 ° C,colder than 0 ° C for a long period of time) observe notes for testing cooling performance. See «A/C SYSTEM COOLING PERFORMANCE, TESTING»(/audi/s6/c5-1999-2004/remont/automatic-hvac-system/#air-conditioning__ac-system-cooling-performance-testing) .

Air extraction vent, checking

1. The sealing flaps -B- in air extraction vent -A- must move freely and be able to close by themselves.

Scheme 27

Note. This illustration shows the air extraction vent after removal of the rear bumper. The vehicle is installed with two air extraction vents (left and right) for forced air extraction. In order for the vehicle interior ventilation to work properly, the air ducts which run through the luggage compartment trim must be unobstructed. Objects placed in the left and right luggage compartment storage boxes may interfere with the operation of the forced extraction vents. This should be checked if symptoms are reported. Obstructions in the air extraction vent -A- may cause the windows to fog up.

Scheme 28

Dust and pollen filter element, removing and installing

1. Remove plenum chamber cover.
2. Release catches on tab -A- and fold back tab.
3. Remove dust and pollen filter element from housing.

Note. To prevent water from entering the dust and pollen filter or the intake duct, make sure that the plenum chamber cover and cowl panel trim are installed correctly. The dust and pollen filter element should be replaced at regular intervals. The dust and pollen filter element must be installed correctly in frame -C-. Arrows -B- indicate the direction of air flow. With additional element of active carbon (combination filter) On vehicle until or from October 1998 there are different versions of the dust and pollen filter and housing (with or without active-carbon-filter element) (different sizes).

Scheme 29

Dust and pollen filter with active carbon filter element

1. With the introduction of Sensor for air quality -G238- ( «SENSOR FOR AIR QUALITY -G238-, FUNCTION»(/audi/s6/c5-1999-2004/remont/heated-glassdefoggers/#on-board-diagnostic-obd-hvac__sensor-for-air-quality-g238-function) ), 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, for example, 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 is 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 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 high basic load (e.g. industrial area). Independently of the basic load, the change-over from fresh- to recirculating mode occurs always, 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 which 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).

Scheme 30

Removing and installing

1. Remove plenum cover.
2. Disconnect harness connector -A- from sensor.
3. Disengage locking mechanism -B- and push sensor -C- down. (Scheme 37)

Terminal assignment in connector -A

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

Scheme 31

A/C system components (in passenger compartment)

Note. After completing service work, always check and erase DTC memory, carry out basic setting and check coding of A/C control head -E87-. Checking cooling performance, see A/C SYSTEM COOLING PERFORMANCE, TESTING . Service work on refrigerant circuit, see REFRIGERANT CIRCUIT, SERVICING . Components marked with an * will be activated during the OUTPUT DIAGNOSTIC TEST MODE (DTM) . Electrical testing is possible on all components marked with ** . See AIR CONDITIONING, ELECTRICAL TESTING . Rear passenger vent "Center" and air ducts in climate control unit in passenger compartment. See AIR DISTRIBUTION IN AIR CONDITIONER AND BODY . Instrument panel outer panel, removing and installing: See INSTRUMENT PANEL .

Note. Items 1 through 12 in the following list (Scheme 38)

Scheme 32

Scheme 33

Scheme 34

1. Actuator for temperature flap left -V158-* With Potentiometer-actuator for temperature flap left -G220-. Removing and installing, see «ACTUATOR FOR TEMPERATURE FLAP LEFT -V158-, REMOVING AND INSTALLING»(/audi/s6/c5-1999-2004/remont/automatic-hvac-system/#air-conditioning).
2. Sender for outlet temperature, floor outlet -G192- ** Removing and installing, see «SENDER FOR OUTLET TEMPERATURE, FLOOR OUTLET -G192-, REMOVING AND INSTALLING»(/audi/s6/c5-1999-2004/remont/automatic-hvac-system/#air-conditioning__sender-for-outlet-temperature-floor-outlet).
3. Not for USA Heater element for auxiliary heater -Z35-*
4. Heater core Removing and installing, see «HEATER CORE, REMOVING AND INSTALLING»(/audi/s6/c5-1999-2004/remont/automatic-hvac-system/#air-conditioning__heater-core-removing-and-installing).
5. Kick down switch The A/C clutch can be switched off by the Engine Control Module (ECM), depending on the current vehicles speed and the desired acceleration. See «READ MEASURING VALUE BLOCK (FUNCTION 08)»(/audi/s6/c5-1999-2004/remont/heated-glassdefoggers/#on-board-diagnostic-obd-hvac__read-measuring-value-block-function-08).
6. Data Link Connector (DLC) for VAG 1551 Scan Tool Connect VAG 1551 scan tool and check Climate Control System. See «ON BOARD DIAGNOSTIC (OBD), INITIATING»(/audi/s6/c5-1999-2004/remont/heated-glassdefoggers/#on-board-diagnostic-obd-hvac).
7. Left Vent Temperature Sensor -G150- ** Removing and installing, see «LEFT VENT TEMPERATURE SENSOR -G150-, REMOVING AND INSTALLING»(/audi/s6/c5-1999-2004/remont/automatic-hvac-system/#air-conditioning__left-vent-temperature-sensor-g150-removing).
8. Instrument panel vent, left Removing and installing, see «LEFT INSTRUMENT PANEL VENT, REMOVING AND INSTALLING»(/audi/s6/c5-1999-2004/remont/automatic-hvac-system/#air-conditioning__left-instrument-panel-vent-removing-and).
9. Defroster vent for side window, left Removing and installing, see «LEFT AND RIGHT SIDE WINDOW DEFROSTER VENTS, REMOVING AND INSTALLING»(/audi/s6/c5-1999-2004/remont/automatic-hvac-system/#air-conditioning__left-and-right-side-window-defroster).
10. Outside Air Temperature Display -G106- * The outside air temperature can be displayed in °C or in °F, depending on setting of A/C Control Head -E87-. NOTE: If the display shows incorrect temperatures, check measuring values of temperature sensors. See «READ MEASURING VALUE BLOCK (FUNCTION 08)»(/audi/s6/c5-1999-2004/remont/heated-glassdefoggers/#on-board-diagnostic-obd-hvac__read-measuring-value-block-function-08).
11. Windshield defroster vent Removing and installing, see «WINDSHIELD DEFROSTER VENT, REMOVING AND INSTALLING»(/audi/s6/c5-1999-2004/remont/automatic-hvac-system/#air-conditioning).
12. Sunlight Photo Sensor -G107- ** Removing and installing, see «SUNLIGHT PHOTO SENSOR -G107-, REMOVING AND INSTALLING»(/audi/s6/c5-1999-2004/remont/automatic-hvac-system/#air-conditioning__sunlight-photo-sensor-g107-removing-and). NOTE: Items 13 through 28 in the following list (Scheme 39)
13. A/C control head -E87- Removing and installing, see «A/C CONTROL HEAD -E87-, REMOVING AND INSTALLING»(/audi/s6/c5-1999-2004/remont/automatic-hvac-system/#air-conditioning__ac-control-head-e87-removing-and). Different versions on vehicles with or without heated seats. Different versions on vehicles with or without Radio-Navigation system. Different versions on vehicles with Climate Control systems "1", "2" and "3", see «A/C CONTROL HEAD -E87-, REMOVING AND INSTALLING»(/audi/s6/c5-1999-2004/remont/automatic-hvac-system/#air-conditioning__ac-control-head-e87-removing-and). Different versions on vehicles up to model year 2001 and from model year 2002. NOTE: The display panel and control buttons are illuminated with LEDs.
14. Instrument Panel Interior Temperature Sensor -G56- and Interior Temperature Sensor Fan -V42- Integrated into A/C Control Head -E87-, cannot be replaced individually.
15. Air conditioning unit with evaporator Removing and installing, see «COMPLETE AIR CONDITIONER UNIT, REMOVING AND INSTALLING»(/audi/s6/c5-1999-2004/remont/automatic-hvac-system/#air-conditioning__complete-air-conditioner-unit-removing-and). Different versions, see «AIR CONDITIONING CHANGES»(/audi/s6/c5-1999-2004/remont/automatic-hvac-system/#air-conditioning) Disassembling and assembling, see «A/C UNIT, DISASSEMBLING AND ASSEMBLING»(/audi/s6/c5-1999-2004/remont/automatic-hvac-system/#air-conditioning__ac-unit-disassembling-and-assembling). WARNING: Only remove the air conditioning unit (condenser) when the refrigerant has been discharged from the A/C system.
16. Footwell vent Can only be replaced when air conditioner unit is removed.
17. Central Air Flap Motor -V70-* With Potentiometer-actuator for temperature flap left -G112-. Removing and installing, see «CENTRAL AIR FLAP MOTOR -V70-, REMOVING AND INSTALLING»(/audi/s6/c5-1999-2004/remont/automatic-hvac-system/#air-conditioning__central-air-flap-motor-v70-removing).
18. Actuator for temperature flap right -V159-* With Potentiometer-actuator for temperature flap left -G221-. Removing and installing, see «ACTUATOR FOR TEMPERATURE FLAP RIGHT -V159-, REMOVING AND INSTALLING»(/audi/s6/c5-1999-2004/remont/automatic-hvac-system/#air-conditioning__actuator-for-temperature-flap-right-v159).
19. Defroster flap motor -V107- * With Potentiometer-actuator for temperature flap left -G135-. Removing and installing, see «DEFROSTER FLAP MOTOR -V107-, REMOVING AND INSTALLING»(/audi/s6/c5-1999-2004/remont/automatic-hvac-system/#air-conditioning__defroster-flap-motor-v107-removing-and). Different versions on vehicles with air conditioning units "1" and as version "2".
20. Fresh Air Blower -V2-** Removing and installing, see «FRESH AIR BLOWER -V2-, REMOVING AND INSTALLING»(/audi/s6/c5-1999-2004/remont/automatic-hvac-system/#air-conditioning__fresh-air-blower-v2-removing-and). Different versions on vehicles with air conditioning units version "1" and version "2".
21. Right Vent Temperature Sensor -G151- ** Removing and installing, see «RIGHT VENT TEMPERATURE SENSOR -G151-, REMOVING AND INSTALLING»(/audi/s6/c5-1999-2004/remont/automatic-hvac-system/#air-conditioning__right-vent-temperature-sensor-g151-removing).
22. Instrument panel vent, right Removing and installing, see «LEFT INSTRUMENT PANEL VENT, REMOVING AND INSTALLING»(/audi/s6/c5-1999-2004/remont/automatic-hvac-system/#air-conditioning__left-instrument-panel-vent-removing-and).
23. Defroster vent for side window, right Removing and installing, see «LEFT AND RIGHT SIDE WINDOW DEFROSTER VENTS, REMOVING AND INSTALLING»(/audi/s6/c5-1999-2004/remont/automatic-hvac-system/#air-conditioning__left-and-right-side-window-defroster).
24. Fresh Air Intake Duct Temperature Sensor -G89- ** Removing and installing, see «FRESH AIR INTAKE DUCT TEMPERATURE SENSOR -G89-, REMOVING AND INSTALLING»(/audi/s6/c5-1999-2004/remont/automatic-hvac-system/#air-conditioning__fresh-air-intake-duct-temperature-sensor).
25. Air Flow Flap Motor -V71- * (on vehicles up to model year 2001) Actuates air flow flap and fresh air/recirculated air flap With Back Pressure Flap Motor Position Sensor -G113- (Recirculation Flap Motor Position Sensor -G143-) Removing and installing, see «AIR FLOW FLAP MOTOR -V71-, REMOVING AND INSTALLING (VEHICLES UP TO MODEL YEAR 2002)»(/audi/s6/c5-1999-2004/remont/automatic-hvac-system/#air-conditioning__air-flow-flap-motor-v71-removing).
26. Control module for fresh air blower -J126- ** Removing and installing, see «CONTROL MODULE FOR FRESH AIR BLOWER -J126-, REMOVING AND INSTALLING»(/audi/s6/c5-1999-2004/remont/automatic-hvac-system/#air-conditioning__control-module-for-fresh-air-blower).
27. Evaporator housing drain Checking, see «EVAPORATOR HOUSING DRAIN VALVE, CHECKING, REMOVING AND INSTALLING»(/audi/s6/c5-1999-2004/remont/automatic-hvac-system/#air-conditioning__evaporator-housing-drain-valve-checking-removing).
28. Instrument panel vent, center Removing and installing, see «CENTER INSTRUMENT PANEL VENT, REMOVING AND INSTALLING»(/audi/s6/c5-1999-2004/remont/automatic-hvac-system/#air-conditioning__center-instrument-panel-vent-removing-and). NOTE: Items 29 through 32 in the following list (Scheme 40)
29. Sealing plug* (Vehicles from model year 2002) Only on vehicles with compressor using A/C Clutch -N25- (Evaporator Vent Temperature Sensor -G263- is not installed, the opening in the air conditioning unit is closed using a sealing plug)
30. Evaporator Vent Temperature Sensor -G263- * (vehicles from model year 2002) Only installed in vehicles with compressor using A/C Compressor Regulator Valve -N280- Removing and installing, see «EVAPORATOR VENT TEMPERATURE SENSOR -G263-, REMOVING AND INSTALLING»(/audi/s6/c5-1999-2004/remont/automatic-hvac-system/#air-conditioning__evaporator-vent-temperature-sensor-g263-removing)
31. Recirculation Flap Motor -V113-* (vehicles from model year 2002) With Recirculation-Flap Motor Position Sensor -G143- Removing-and installing, see «RECIRCULATION FLAP MOTOR -V113-, REMOVING AND INSTALLING (VEHICLES FROM MODEL YEAR 2002)»(/audi/s6/c5-1999-2004/remont/automatic-hvac-system/#air-conditioning__recirculation-flap-motor-v113-removing-and)
32. Air Flow Flap Motor -V71-* (vehicles from model year 2002) With Back Pressure Flap Motor Position Sensor -G113- Removing and installing, see «AIR FLOW FLAP MOTOR -V71-, REMOVING AND INSTALLING (VEHICLES UP TO MODEL YEAR 2002)»(/audi/s6/c5-1999-2004/remont/automatic-hvac-system/#air-conditioning__air-flow-flap-motor-v71-removing)

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

The A/C control heads are coordinated differently, the allocation must be observed when replacing the A/C control head. See A/C CONTROL HEAD -E87-, CODING and observe notes in parts catalog as well.

1. In the period from week 36 to week 44, 1998, there was a running change in production from version 1 air conditioner to version 2 air conditioner. The two versions can be differentiated by specific characteristics. See «CHARACTERISTICS OF AIR CONDITIONER VERSIONS 1 AND 2»(/audi/s6/c5-1999-2004/remont/automatic-hvac-system/#air-conditioning) . In vehicles with air conditioning unit "1" only A/C control heads with part number and including index "G" can be installed. In vehicles with air conditioning unit "2" only A/C control heads with part number from index "H" can be installed. Vehicles with 8 cylinder engines are only equipped with air conditioning unit version "2".
2. Starting with model year 2002, A/C Control Heads -E87- are installed that communicate with other control modules via the CAN-bus system. See «A/C CONTROL HEAD -E87-, CODING»(/audi/s6/c5-1999-2004/remont/heated-glassdefoggers/#on-board-diagnostic-obd-hvac__ac-control-head-e87-coding) .
3. Check DTC memory before removing A/C Control Head -E87-.
4. After replacing A/C Control Head -E87- always: Check or enter new coding. Carry out basic setting. Check DTC memory.
5. The display panel on A/C Control Head -E87- changed from ° C to ° F and back by pressing and holding the "Recirculate air" button, then pressing the temperature "+" button for the driver's side.
6. If A/C Control Head -E87- remains on after the ignition has been switched off, test for short circuit to B+ in the wiring to terminal 1 of connector -D- (connection for auxiliary heater) using wiring diagram.
7. If a new control head is installed and its display panel flashes (for about 2 minutes) when the ignition is switched on, code the A/C control head and carry out basic setting.
8. If the two display panels do not light up when the ignition is switched on, restore voltage supply to terminal 58d (dimming) for -E87- according to wiring diagram.

Removing and installing, Vehicles without Radio Navigation system

1. Remove radio. See «RADIO SYSTEMS»(/audi/s6/c5-1999-2004/remont/communication-devices/#radio-telephone-navigation-trip-computer) .
2. Remove center trim section of instrument panel. See «INSTRUMENT PANEL»(/audi/s6/c5-1999-2004/remont/exteriorinterior-trim/#interior-trim) .
3. Remove bolts -A-.

Note. After removing the two lower screws -A-, the clips located in front of the fastening straps on A/C Control Head -E87- should be tipped forward and removed using a screwdriver.

Scheme 35

1. Remove A/C control head -B-.

Removing and installing, Vehicles with Radio Navigation system

1. Vehicles with Radio-Navigation system Remove Radio-Navigation system. See «RADIO, TELEPHONE, NAVIGATION, TRIP COMPUTER»(/audi/s6/c5-1999-2004/remont/communication-devices/#radio-telephone-navigation-trip-computer). Remove bolts -A-. (Scheme 42) Lift A/C control head -B- up slightly and remove in direction of arrow.

Scheme 36

Note. In these vehicles, A/C control head is held underneath by latching tabs -C- and -D-.

Scheme 37

1. All models Press back harness connector release catches -F- and disconnect harness connectors -A- through -D-. (Scheme 43) Press back harness connector releases catches -G- and disconnect harness connector -E- (for rear window heating).

Note. The display panel and control buttons are illuminated with LEDs (which cannot be replaced). Different versions of A/C Control Head -E87- are available as replacement parts depending on vehicle equipment (for example, with or without openings for heated seat switches). To remove heated seat switch, press back retainer tabs -A- and pull switch -B- out of A/C Control Head -E87- from behind. (Scheme 44) If Instrument Panel Interior Temperature Sensor -G56- is giving an incorrect reading, make sure intake grill on panel is not obstructed.

Scheme 38

Control module for fresh air blower -J126-, removing and installing

1. Remove glove box. See «GLOVE BOX, REMOVING AND INSTALLING»(/audi/s6/c5-1999-2004/remont/mirrors/#interior-equipment__glove-box-removing-and-installing) .
2. Disconnect harness connector -A-.
3. Remove bolt -B-.
4. Remove control module for fresh air blower -C-.

Scheme 39

Fresh air blower -V2-, removing and installing

1. Remove glove box See «GLOVE BOX, REMOVING AND INSTALLING»(/audi/s6/c5-1999-2004/remont/mirrors/#interior-equipment__glove-box-removing-and-installing) .
2. Disconnect harness connector -A-.
3. Remove bolts -B-.
4. Remove fresh air blower -C- from air conditioning unit in direction of arrow.

Note. The blower wheel for the fresh air blower installed in version "2" air conditioning unit is approx. 10 mm shorter than the one for version "1".

Scheme 40

Sender for outlet temperature, floor outlet -G192-, removing and installing

1. Remove storage compartment on driver's side. See «DRIVER'S STORAGE COMPARTMENT, REMOVING»(/audi/s6/c5-1999-2004/remont/mirrors/#interior-equipment__drivers-storage-compartment-removing) .
2. Disconnect harness connector -A-.
3. Turn sensor -B- 90° (1/4 turn) and pull out of air duct.

Scheme 41

Left vent temperature sensor -G150-, removing and installing

1. Remove storage compartment on driver's side. See «DRIVER'S STORAGE COMPARTMENT, REMOVING»(/audi/s6/c5-1999-2004/remont/mirrors/#interior-equipment__drivers-storage-compartment-removing) .
2. Disconnect harness connector -A-.
3. Turn sensor -B- 90° (1/4 turn) and pull out of air duct.

Scheme 42

Right vent temperature sensor -G151-, removing and installing

1. Remove glove box See «GLOVE BOX, REMOVING AND INSTALLING»(/audi/s6/c5-1999-2004/remont/mirrors/#interior-equipment__glove-box-removing-and-installing) .
2. Disconnect harness connector -A-.
3. Turn sensor -B- 90° (1/4 turn) and pull out of air duct.

Scheme 43

Evaporator vent temperature sensor -G263-, removing and installing

Note. Evaporator Vent Temperature Sensor -G263- applies only to vehicles from model year 2002 with a compressor using A/C Compressor Regulator Valve -N280-. On vehicles from model year 2002 and a compressor with A/C Clutch -N25-, the opening is closed with a plug.

1. Remove glove compartment: See «GLOVE BOX, REMOVING AND INSTALLING»(/audi/s6/c5-1999-2004/remont/mirrors/#interior-equipment__glove-box-removing-and-installing) .
2. Disconnect connector -B-.
3. Turn sensor -B- 90° (1/4 turn) and pull out air conditioning unit.

Scheme 44

Fresh air intake duct temperature sensor -G89-, removing and installing

1. Remove glove box See «GLOVE BOX, REMOVING AND INSTALLING»(/audi/s6/c5-1999-2004/remont/mirrors/#interior-equipment__glove-box-removing-and-installing) .
2. Disconnect harness connector -A-.
3. Turn sensor -B- 90° (1/4 turn) and pull out of air duct.

Scheme 45

Sunlight photo sensor -G107-, removing and installing

1. Carefully pry off cover -A-.
2. Remove bolt -B-.
3. Remove photo sensor.

Scheme 46

Defroster flap motor -V107-, removing and installing

1. Remove glove box. See «GLOVE BOX, REMOVING AND INSTALLING»(/audi/s6/c5-1999-2004/remont/mirrors/#interior-equipment__glove-box-removing-and-installing).
2. Disconnect harness connector -A-. (Scheme 53)
3. Remove 3 bolts -B-.
4. Disengage actuating arm and remove positioning motor.

Scheme 47

Note. The lever arm of the stepper motor installed on the version "2" air conditioning unit is different from the arm installed on version "1".

1. Remove bolts -C- (3x) and detach positioning motor -B- from bracket -D-.

Notes for installation

1. After installing, always carry out On Board Diagnostic (OBD) of air conditioning system. See «ON BOARD DIAGNOSTIC (OBD), INITIATING»(/audi/s6/c5-1999-2004/remont/heated-glassdefoggers/#on-board-diagnostic-obd-hvac) .
2. When installing the positioning motor, make sure that the actuator arm is properly engaged.
3. Install the wiring harness so that it cannot come in contact with any moving parts (e.g. the actuating arm on the positioning motor).

Scheme 48

Scheme 49

1. Remove storage compartment on driver's side. See «DRIVER'S STORAGE COMPARTMENT, REMOVING»(/audi/s6/c5-1999-2004/remont/mirrors/#interior-equipment__drivers-storage-compartment-removing).
2. Remove entire center section of instrument panel and also reinforcement bracket. See «INSTRUMENT PANEL»(/audi/s6/c5-1999-2004/remont/exteriorinterior-trim/#interior-trim).
3. Remove left hand instrument panel support by unscrewing bolt -A-, bolts -B- (2x) and bolts -C- (2x). (Scheme 54)
4. Remove wiring harness -D- from left instrument panel support.
5. Disconnect harness connector -A-. (Scheme 55)
6. Remove 3 bolts -B-.
7. Carefully disengage coupling rod -C- using screwdriver -D- and remove positioning motor.

1. After installing, always carry out On Board Diagnostic (OBD) of air conditioning system. See «ON BOARD DIAGNOSTIC (OBD), INITIATING»(/audi/s6/c5-1999-2004/remont/heated-glassdefoggers/#on-board-diagnostic-obd-hvac).
2. When installing the positioning motor, make sure that coupling rod -C- is properly engaged. (Scheme 55)
3. Install the wiring harness so that it cannot come in contact with any moving parts (for example, the actuating arm on the positioning motor).

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

1. Remove glove box. See «GLOVE BOX, REMOVING AND INSTALLING»(/audi/s6/c5-1999-2004/remont/mirrors/#interior-equipment__glove-box-removing-and-installing).
2. Disconnect harness connector -A-. (Scheme 56)
3. Remove 3 bolts -B-.
4. Carefully disengage coupling rod -C- using screwdriver -D- and remove positioning motor.

Scheme 50

1. After installing, always carry out On Board Diagnostic (OBD) of air conditioning system. See «ON BOARD DIAGNOSTIC (OBD), INITIATING»(/audi/s6/c5-1999-2004/remont/heated-glassdefoggers/#on-board-diagnostic-obd-hvac).
2. When installing the positioning motor, make sure that coupling rod -C- is properly engaged. (Scheme 56)
3. Install the wiring harness so that it cannot come in contact with any moving parts (for example, the actuating arm on the positioning motor).

Central air flap motor -V70-, removing and installing

1. Remove glove box. See «GLOVE BOX, REMOVING AND INSTALLING»(/audi/s6/c5-1999-2004/remont/mirrors/#interior-equipment__glove-box-removing-and-installing).
2. Disconnect harness connector -A-. (Scheme 57)
3. Remove 3 bolts -B-.
4. Carefully disengage coupling rod -C- using screwdriver -D- and remove positioning motor.

Scheme 51

1. After installing, always carry out On Board Diagnostic (OBD) of air conditioning system. See «ON BOARD DIAGNOSTIC (OBD), INITIATING»(/audi/s6/c5-1999-2004/remont/heated-glassdefoggers/#on-board-diagnostic-obd-hvac).
2. When installing the positioning motor, make sure that coupling rod -C- is properly engaged. (Scheme 57)
3. When installing the positioning motor, make sure that the location pin on the actuating arm engages properly in the can plate.
4. Install the wiring harness so that it cannot come in contact with any moving parts (for example, the actuating arm on the positioning motor).

Air flow flap motor -V71-, removing and installing (vehicles up to model year 2002)

Note. The position motor activates the air flow flap and also the fresh air/recirculation air flap via change over lever -A-. (Scheme 58) As of model year 2002, the fresh air/recirculating air flap is no longer operates via the position motor -V71-, but instead via recirculation flap motor -V113-. With the change of the A/C control head -E87- and the implementation of a second position motor at the intake air passage, the motor was changed.

Scheme 52

1. Remove glove box: See «GLOVE BOX, REMOVING AND INSTALLING»(/audi/s6/c5-1999-2004/remont/mirrors/#interior-equipment__glove-box-removing-and-installing).
2. Disconnect harness connector -A-. (Scheme 59)
3. Remove bolts -B- (3x). (Scheme 59)
4. Disengage actuating arm and remove positioning motor.
5. Remove bolts -C- (3x) and detach positioning motor -B- from bracket.

Scheme 53

Notes on installation

1. After installing, always perform On Board Diagnostic (OBD) of air conditioning system. See «ON BOARD DIAGNOSTIC (OBD), INITIATING»(/audi/s6/c5-1999-2004/remont/heated-glassdefoggers/#on-board-diagnostic-obd-hvac).
2. Install the wiring harness so that it cannot come into contact with any moving parts (e.g. the actuating arm on the positioning motor).
3. When installing the positioning motor, make sure that locating pins -D- and -E- engage properly in actuating arms -F- and -G-. (Scheme 59)

Recirculation flap motor -V113-, removing and installing (vehicles from model year 2002)

Note. This positioning motor actuates the fresh air/recirculating air flap.

1. Remove glove box. See «GLOVE BOX, REMOVING AND INSTALLING»(/audi/s6/c5-1999-2004/remont/mirrors/#interior-equipment__glove-box-removing-and-installing).
2. Recirculation Flap Motor -V113-, removing, see «AIR FLOW FLAP MOTOR -V71-, REMOVING AND INSTALLING (VEHICLES UP TO MODEL YEAR 2002)»(/audi/s6/c5-1999-2004/remont/automatic-hvac-system/#air-conditioning__air-flow-flap-motor-v71-removing).
3. Disconnect harness connector -A-. (Scheme 60)
4. Remove bolt -B-.

Scheme 54

Note. When removing screw -B-, if necessary reach the bolt from underneath in the recirculating intake area.

1. Remove bolts -C-. (Scheme 60)
2. Remove positioning motor.

1. After installing, always carry out On Board Diagnostic (OBD) of air conditioning system. See «ON BOARD DIAGNOSTIC (OBD), INITIATING»(/audi/s6/c5-1999-2004/remont/heated-glassdefoggers/#on-board-diagnostic-obd-hvac).
2. Install the wiring harness so that it cannot come in contact with any moving parts (e.g. the actuating arm on the positioning motor).
3. When installing positioning motor, make sure guiding -D- engages properly in lever -E-. (Scheme 60)

Instrument panel vent removal tool, making

1. Bend piece of wire (3 mm) as shown.
2. Measurement x = 12 mm.
3. Use hammer to angled piece to width y = 2 mm.

Scheme 55

Center instrument panel vent, removing and installing

1. Remove glove box. See «GLOVE BOX, REMOVING AND INSTALLING»(/audi/s6/c5-1999-2004/remont/mirrors/#interior-equipment__glove-box-removing-and-installing).
2. Instrument panel piece trim, removing See «STORAGE COMPARTMENTS, COVERS AND TRIM PARTS»(/audi/s6/c5-1999-2004/remont/mirrors/#interior-equipment). NOTE: The instrument panel vent -1- is fastened via clips -4- in the instrument panel. (Scheme 62)
3. Open vents -2-.
4. Insert special tool -A- in instrument panel vent and turn to disengage upper retainers. (Scheme 63)
5. Use screwdriver -B- to prevent upper retainers from engaging again.

Scheme 56

Note. If the lower retainers cannot be loosened from the front

1. Remove entire center section of instrument panel and also reinforcement bracket. See «STORAGE COMPARTMENTS, COVERS AND TRIM PARTS»(/audi/s6/c5-1999-2004/remont/mirrors/#interior-equipment).
2. Remove storage compartment on driver's side. See «GLOVE BOX, REMOVING AND INSTALLING»(/audi/s6/c5-1999-2004/remont/mirrors/#interior-equipment__glove-box-removing-and-installing).
3. Disengage lower retainer using screwdriver -C-. (Scheme 63)

1. Remove vent from instrument panel from front using screwdriver -3-. (Scheme 64)

Scheme 57

Left instrument panel vent, removing and installing

1. Remove storage compartment on driver's side. See «GLOVE BOX, REMOVING AND INSTALLING»(/audi/s6/c5-1999-2004/remont/mirrors/#interior-equipment__glove-box-removing-and-installing).
2. Insert special tool -A- in instrument panel vent and turn to disengage upper retainers. (Scheme 65)
3. Use screwdriver -B- to prevent retainers from engaging again.
4. Disengage lower retainer using screwdriver -C-.
5. Remove vent from instrument panel from front.

Scheme 58

Scheme 59

1. Remove instrument panel trim. See «INSTRUMENT PANEL»(/audi/s6/c5-1999-2004/remont/exteriorinterior-trim/#interior-trim) .
2. Remove speed nuts -S- and defroster vent -B- from instrument panel trim.

Right instrument panel vent, removing and installing

1. Remove glove box. See «GLOVE BOX, REMOVING AND INSTALLING»(/audi/s6/c5-1999-2004/remont/mirrors/#interior-equipment__glove-box-removing-and-installing) .
2. Instrument panel piece trim, removing: See «INSTRUMENT PANEL»(/audi/s6/c5-1999-2004/remont/exteriorinterior-trim/#interior-trim) .
3. Insert special tool -A- in instrument panel vent and turn to disengage upper retainers.
4. Use screwdriver -B- to prevent retainers from engaging again.
5. Disengage lower retainer using screwdriver -C-.
6. Remove vent from instrument panel from front.

Scheme 60

Left and right side window defroster vents, removing and installing

1. Carefully pry out of instrument panel using screwdriver -A-.

Scheme 61

Heater core, removing and installing

1. Remove plenum chamber cover.
2. Disconnect battery cables and remove battery.

Note. Obtain radio code before disconnecting battery. On vehicles with power seats, move the seats back as far as possible before disconnecting the battery. For vehicles build up to October 1998.

1. Remove complete windshield wipers. See «WINDSHIELD WIPER AND WASHER SYSTEM - UP TO 2000»(ref-196296) or «WINDSHIELD WIPER AND WASHER SYSTEM - 2001 AND UP»(/audi/s6/c5-1999-2004/remont/wiperwasher-systems/#windshield-wiper-and-washer-system-2001-and-up).
2. Remove grommet (in pass through hole in plenum chamber).
3. Loosen screw -A- and screw out 10 mm, or remove. (Scheme 69)

Scheme 62

1. Vehicles build from October 1998 through December 1998: Check whether grommet -A- is present in pass-through hose in plenum. If grommet -A- is present, completely remove windshield wiper. If grommet -A- is not present, remove instrument panel shell. (Scheme 70) See «INSTRUMENT PANEL»(/audi/s6/c5-1999-2004/remont/exteriorinterior-trim/#interior-trim).

Scheme 63

Note. Up to October 1998, the central tube for the instrument panel is fastened to the body with a bolt. To remove the bolt, the windshield wiper must be removed. Starting October 1998, there was a running change in the fastening method for the central tube. Fastening is now carried out with a bracket and a screw under the instrument panel outer shell on the windshield cross member (to remove, the outer instrument panel shell has to be removed). Vehicles starting January 1999

Note. From June 1999 different mounting brackets for the brake and clutch pedal were installed (as a running chang, first on vehicles with accelerator pedal sensor), on vehicles with these mounting brackets the instrument panel cross member does not have to be loosened anymore to remove the heater core.

Removing heater core

1. Release pressure in coolant system by opening cap on coolant expansion tank.
2. Clamp off and disconnect both coolant hoses leading to heater core in air conditioner unit (e.g. using VAG 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. Bleed cooling circuit. See appropriate COOLING SYSTEM, MECHANICAL article.

Scheme 64

1. Place container under connection -A- and carefully blow out coolant from heater core (using compressed air) via connection -B-.
2. Remove grommet -C-.
3. Remove storage compartment on driver's side. See «DRIVER'S STORAGE COMPARTMENT, REMOVING»(/audi/s6/c5-1999-2004/remont/mirrors/#interior-equipment__drivers-storage-compartment-removing).
4. Unscrew bolt -A- and remove bracket -B-. (Scheme 73)
5. Loosen clamp -C-. (Scheme 73)
6. Pull heater core -D- out of air conditioner unit slightly. (Scheme 73)
7. Pull two coolant lines -E- out of heater core. (Scheme 73)
8. Remove heater core

Scheme 65

Note. If heater core cannot be pulled out of air conditioning unit (touching mounting bracket of brake pedal and clutch pedal), loosen instrument panel cross member. Always replace clamps -C- and O-rings -F-. Install clamps -C- as shown in the illustration, making sure that they are not in contact with air conditioner unit. Before installing the storage compartment on the driver's side, check the cooling system for leaks. Before installing the storage compartment on the driver's side, make sure that the Wide Open Throttle (WOT) stop of the accelerator pedal is installed in the correct position. Bracket -B- is only available on version "1", from version "2" the cover supports the cooling pipes. Loosen instrument panel cross member from vehicle.

Note. Instrument panel cross member should only be loosened on vehicles when heater core cannot be pulled out of air conditioning unit (touching mounting bracket for brake and clutch pedal).

Scheme 66

Scheme 67

Scheme 68

Scheme 69

Scheme 70

1. Removing instrument panel outer shell (not necessary on all vehicles, see notes). See «INSTRUMENT PANEL»(/audi/s6/c5-1999-2004/remont/exteriorinterior-trim/#interior-trim).
2. Remove bolt -A-.
3. Removing instrument panel center part (not necessary on all vehicles, see notes). See «INSTRUMENT PANEL»(/audi/s6/c5-1999-2004/remont/exteriorinterior-trim/#interior-trim).
4. Loosen right instrument panel cross member (remove two bolts -2-).
5. Remove bolts -A- and detach left instrument panel brace from body.
6. Remove screws -B- and remove cover -C-. (Scheme 76)
7. Remove bolt -1- and detach pedal bracket from instrument panel cross member.
8. Push adjustable steering column in as far as will go.
9. Remove left instrument panel cover. See «INSTRUMENT PANEL»(/audi/s6/c5-1999-2004/remont/exteriorinterior-trim/#interior-trim).
10. Unscrew nuts -2- far enough to allow left side of instrument panel module to be pulled back about 10 mm (0.394 in.)
11. Loosen left instrument panel cross member of body. See «INSTRUMENT PANEL»(/audi/s6/c5-1999-2004/remont/exteriorinterior-trim/#interior-trim).
12. Pull back left side of instrument panel module for enough to allow heater core to be taken out of air conditioner unit (past pedal bracket), and secure heater core in position to prevent it from sliding back.

Installing heater core

Installation of the heater core is the reverse of removal.

1. Before installing the storage compartment on the driver's side, check the cooling system for leaks (fill coolant circuit, bleed and pressure test).

Changes implemented from June 1998

Between week 36 and week 44 of 1998 the production of air conditioning unit version "1" has been converted to air conditioning version "2" as a running change. Both versions can be differentiated through specific characteristics. See CHARACTERISTICS OF AIR CONDITIONER VERSIONS 1 AND 2 .

Note. Vehicles with 8 cylinder engines are only equipped with air conditioning unit version "2". When replacing the air conditioning unit or the A/C control head, always observer the additional notes in the parts catalog.

1. A/C control head -E87- Only A/C control heads with part number and until index "G" must be installed in vehicles with air conditioning unit version "1" Only A/C control heads with part number and from index "H" must be installed in vehicles with air conditioning unit version "2"
2. Intermediate piece for defroster channel Air conditioning units version "1" have an intermediate piece with two openings to the air conditioning unit installed. Air conditioning units version "2" have an intermediate piece with one opening to the air conditioning unit installed.
3. Defroster Flap Motor -V107-. The lever arm on Defroster Flap Motor -V107- is different between air conditioning unit "1" and "2".
4. Fresh Air Blower -V2- The blower wheel for the fresh air blower installed in version "2" air conditioning unit is approx. 10 mm shorter than the one for version "1".

1. Air distribution housing Housing On air conditioning version "1", the air guide to the intermediate part for defroster channel takes place via two openings, from version "2" the two openings have been combined into one opening. Air distribution flaps in air distribution housing Position of the three air flow flaps to the instrument panel vents. From version "2", when the center flap is closed the two outer flaps remain a little bit open (angle between both flaps approx. 40 degree), therefore a small amount of air can always flow to the right and left instrument panel vents. On version "1" all three flaps close completely. Evaporator From version "2", the width of the evaporator is 32 mm less than in version "1" (58 mm instead of 90 mm) Starting with version "2", the evaporator cannot be removed from the air distributor housing anymore (the housing must be disassembled, due to the changed refrigerant line connection). The refrigerant lines have been adapted to the evaporator.
2. Air flow duct with intake duct. The air duct has been adapted to the changed fresh air blower fan. The blower wheel for the fresh air blower installed in version "2" air conditioning unit is approx. 10 mm shorter than the one for version "1". From version "2", the air duct at the fresh air blower fan is narrower than the air duct in version "1".

Scheme 71

Scheme 72

Scheme 73

Scheme 74

1. Remove dust and pollen filter. See «DUST AND POLLEN FILTER ELEMENT, REMOVING AND INSTALLING»(/audi/s6/c5-1999-2004/remont/automatic-hvac-system/#air-conditioning__dust-and-pollen-filter-element-removing). Intake housing and fresh air blower in version "1" Air duct -A- can be seen through the fresh air intake opening. Intake housing and fresh air blower in version "2" No air duct is present.
2. Remove glove box: See «GLOVE BOX, REMOVING AND INSTALLING»(/audi/s6/c5-1999-2004/remont/mirrors/#interior-equipment__glove-box-removing-and-installing). Air duct in version "1" Air duct in version "2" The air duct is designed to be smaller in area -A- than the duct in version "1". (Scheme 82) Bracket -B- extends out more than in version "1". (Scheme 82)

Scheme 75

Scheme 76

1. Air distributor housing in version "1" The air is directed to the spacer for defroster duct through two openings -A-. (Scheme 83) The air flaps -B- close fully at the same time. Flaps -A-, -B- and -C- are made of sheet steel.
2. Air distributor housing in version "2" The air is directed to the spacer (intermediate piece) for defroster duct through one opening -A-. (Scheme 84) Flaps -C- remain open slightly when the center flap -B- is closed (angle between the flaps is approximately 40 degree) Flaps -A-, -B- and -C- are made of plastic.

Changes implemented from model year 2002

Note. The change over of the climate control conversion on the Audi allroad does not occur with the 2001 to 2002 model year change, but as a running change in model year 2002. When replacing the air conditioning unit or the A/C control head, always observe the additional notes in the parts catalog.

From model year 2002

1. Air conditioner unit versions "3" are installed.
2. Starting with model year 2002, A/C Control Heads -E87- are installed that communicate with other control modules via the CAN-bus system. See «A/C CONTROL HEAD -E87-, CODING»(/audi/s6/c5-1999-2004/remont/heated-glassdefoggers/#on-board-diagnostic-obd-hvac__ac-control-head-e87-coding) .
3. Depending on engine type, compressors with A/C clutch -N25- or A/C Compressor Regulator Valve -N280- are installed. See «COMPRESSOR, WITH A/C CLUTCH -N25»(/audi/s6/c5-1999-2004/remont/automatic-hvac-system/#air-conditioning__compressor-with-ac-clutch-n25) and «COMPRESSOR, WITH A/C COMPRESSOR REGULATOR VALVE -N280»(/audi/s6/c5-1999-2004/remont/automatic-hvac-system/#air-conditioning__compressor-with-ac-compressor-regulator-valve) .
4. Sensor for air quality -G238- is installed. See «SENSOR FOR AIR QUALITY -G238-, REMOVING AND INSTALLING»(/audi/s6/c5-1999-2004/remont/automatic-hvac-system/#air-conditioning__sensor-for-air-quality-g238-removing)
5. An additional positioning motor for the fresh air/recirculating flap is installed (only on vehicles with left hand steering). See «RECIRCULATION FLAP MOTOR -V113-, REMOVING AND INSTALLING (VEHICLES FROM MODEL YEAR 2002)»(/audi/s6/c5-1999-2004/remont/automatic-hvac-system/#air-conditioning__recirculation-flap-motor-v113-removing-and) .

1. Air distribution housing The air distributor housing has an additional opening, that is the installation location of Evaporator Vent Temperature Sensor -G263-. See «EVAPORATOR VENT TEMPERATURE SENSOR -G263-, REMOVING AND INSTALLING»(/audi/s6/c5-1999-2004/remont/automatic-hvac-system/#air-conditioning__evaporator-vent-temperature-sensor-g263-removing) .
2. Air duct housing with intake duct Version "3" has an intake duct installed, where the air recirculating/fresh air flap is activated via an additional positioning motor. See «RECIRCULATION FLAP MOTOR -V113-, REMOVING AND INSTALLING (VEHICLES FROM MODEL YEAR 2002)»(/audi/s6/c5-1999-2004/remont/automatic-hvac-system/#air-conditioning__recirculation-flap-motor-v113-removing-and) .

Air distribution in air conditioner

Note. Starting September 1998, there was a running change in production from the version "1" air conditioner to the version "2" air conditioner. See AIR CONDITIONING CHANGES . The way air is distributed over the air flaps in the air distributor housing differs between version "1" and "2". See AIR CONDITIONING CHANGES .

Note. The following list refers to items in (Scheme 85).

1. A - Plenum chamber/dust and pollen filter
2. B - Front passengers footwell
3. C - Fresh Air Blower -V2
4. D - Evaporator
5. E - Heater core
6. F - Not for USA (Heater element for auxiliary heater -Z35-)
7. G - Division between driver's side and passenger's side
8. H - To instrument panel vents Modified positions of central flaps to each other (see central flap).
9. J - To windshield vents On air conditioning version "1", the air guide to the intermediate piece (spacer) for defroster channel takes place via two openings, from version "2" the two openings have been combined into one opening.
10. K - To rear footwell vents
11. L - To footwell vents
12. M - Wire mesh

Scheme 77

Note. The following list refers to items in (Scheme 85).

1. Air flow flaps
2. Fresh air/recirculated air flap
3. Temperature flap 1 One flap for driver's side and one for passenger side
4. Temperature flap 2 One flap for driver's side and one for passenger side
5. Central flap From version "2", when the center flap is closed the two outer flaps remain a slightly open (angle between both flaps approx. 40 degree), on version "1" all flaps close simultaneously.
6. Defroster flap
7. Footwell flap

Air ducts in vehicle interior

Note. The following list refers to items in (Scheme 86).

1. Intermediate piece for defroster channel Can only be replaced when instrument cross member unit is removed. Different versions, on air conditioning version "1", the air guide from the air conditioner takes place via two openings, from version "2" these two openings have been combined into one opening.
2. Air conditioner
3. Air duct to right instrument panel vent
4. Air duct to left instrument panel vent
5. Central air duct The position of the central flaps is different, from version "2", when the center flap is closed the two outer flaps remain a slightly open (angle between both flaps approx. 40 degree), on version "1" all flaps close simultaneously.
6. Connecting duct, right Attached to center section of instrument panel
7. Connecting duct, left Attached to center section of instrument panel
8. Connecting duct, right Attached to instrument panel center section trim
9. Connecting duct, left Attached to instrument panel center section trim
10. Center air duct, rear Installed in center console
11. Intermediate - section for rear center vent
12. Center vent, rear Pull out of center console using special tool
13. Footwell vent Can only be replaced when air conditioner unit is removed.
14. Connecting duct, right
15. Connecting duct, left
16. Rear footwell vent, passenger's side
17. Rear footwell vent, driver's side

Scheme 78

A/C system cooling performance, testing

Note. Under certain operating conditions, residual moisture in refrigerant circuit can lead to an ice build-up at 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: 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. 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. Corrective action: For vehicles as of model year 2002 and a compressor with A/C Compressor Regulator Valve -N280-, check measured value of Evaporator Vent Temperature Sensor -G263-. See DISPLAY GROUP 010: MEASURING VALUES FOR EVAPORATOR VENT TEMPERATURE SENSOR -G263-, FRESH AIR INTAKE DUCT TEMPERATURE SENSOR -G89-, OUTSIDE AIR TEMPERATURE SENSOR -G17- AND CALCULATED OUTSIDE TEMPERATURE TRANSMITTED TO INSTRUMENT CLUSTER . If measured value of the sensor is too low under operating conditions specified by customer (at an ambient temperature above 0 6 C, colder than 0 C for a long period of time although A/C Compressor Regulator Valve -N280- is not currently being activated), transfer vehicle to an authorized service shop for A/C systems. In vehicles without Evaporator Vent Temperature Sensor -G263- e.g. via Sender for outlet temperature, floor outlet -G192-, check at the adjustment: "Temperature Lo" for driver's- and passenger side, 4 or 5 bars for fresh air blower RPM, air outlet in footwell and fresh air operation under operating conditions specified by customer. If measured value of the sensor is too low (at an ambient temperature above 0 ° C, colder than 0 ° C for a long period of time), transfer vehicle to an authorized service shop for A/C systems. 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, transfer vehicle to an authorized service shop for A/C systems. Bring the determined deficiency to the attention of the authorized service shop for A/C systems, the necessary work can only be performed there (draining refrigerant circuit, replacing accumulator and then evacuating the refrigerant circuit for a minimum of 3 hours).

Test requirements

1. Radiator and condenser clean (clean if necessary)
2. Ribbed belt OK and correctly tensioned and drive plate actually drives compressor (6 and 8 cylinder gas engine).
3. Compressor drive unit (connection between compressor and engine) is correctly installed (only Audi Allroad with 4.2 L engine, see «COMPRESSOR DRIVE UNIT, CHECKING, REPLACING»(/audi/s6/c5-1999-2004/remont/automatic-hvac-system/#air-conditioning__compressor-drive-unit-checking-replacing) ).
4. Air flow through dust and pollen filter not obstructed by dirt
5. Air conditioner unit properly sealed (when fresh air blower is at maximum speed setting, no additional air is drawn in; air delivery is via vents only)
6. Vehicle not standing in direct sunlight Engine at normal operating temperature All instrument panel vents open.
7. Engine running and A/C control head -E87- set as follows: AUTO mode Compressor switched on (LED in ECON button not lit up) Temperature selection LO (for both driver's and passenger's side) Compressor activated (A/C clutch -N25- switched on) A/C Compressor Regulator Valve -N280- is switched on (on vehicles using -N280-. See «MEASURING VALUE BLOCKS (VEHICLES FROM MODEL YEAR 2002)»(/audi/s6/c5-1999-2004/remont/heated-glassdefoggers/#on-board-diagnostic-obd-hvac) (display group 001 and 002). Coolant Fan -V7- running (speed depends on pressure in refrigerant circuit and engine temperature) Fresh Air Blower -V2- running at maximum speed Fresh air/recirculated air flap moved to "recirculated air" mode (within 1 minute of starting engine) Air should come out of the instrument panel vents Both temperature flaps in "cooling" position

Note. Check DTC memory if one test requirement is not attained. See CHECK DTC MEMORY (FUNCTION 02) . And carry out output Diagnostic Test Mode. See OUTPUT DIAGNOSTIC TEST MODE (DTM) .

Preparatory steps

1. Connect VAG 1551 scan tool and press buttons -0- and -8- to insert AC/Heating Electronics" address word 08 and advance program until "Select function XX" appears on display. See «ON BOARD DIAGNOSTIC (OBD), INITIATING»(/audi/s6/c5-1999-2004/remont/heated-glassdefoggers/#on-board-diagnostic-obd-hvac) .
2. Carry out basic setting and check coding. See «BASIC SETTING (FUNCTION 04)»(/audi/s6/c5-1999-2004/remont/heated-glassdefoggers/#on-board-diagnostic-obd-hvac__basic-setting-function-04) and «ON BOARD DIAGNOSTIC (OBD), INITIATING»(/audi/s6/c5-1999-2004/remont/heated-glassdefoggers/#on-board-diagnostic-obd-hvac) .
3. Close hood and sunroof.
4. Measure ambient temperature.
5. Close doors and windows.

Scheme 79

1. Switch on ignition.
2. Select AUTO mode on A/C control head -E87- and switch temperature setting to LO (both driver's side and passenger's side).
3. Start engine (the compressor will run).
4. Press button for recirculated air (LED in button will light up)
5. Increase engine speed to 2000 RPM (timed period begins)
6. Measure air temperature in center instrument panel vents. Compare measured values with graph.
7. A - Air temperature in "center" instrument panel vent
8. B - Measured ambient temperature
9. C - Permissible temperature range for air vents.
10. After 5 minutes (depending on ambient temperature) the temperature of air from the center instrument panel vents should settle to within tolerance -C- on the graph.

Note. If the specified values are not obtained, determine malfunction when deviates from specified value. See IDENTIFYING MALFUNCTIONS IF SPECIFIED VALUES ARE NOT OBTAINED . The temperature of the air from the vents can also be measured via the vent temperature sensors. See READ MEASURING VALUE BLOCKS (VEHICLES UP TO MODEL YEAR 2001) , display groups 007 and 008).

Scheme 80

1. To actuation of temperature flaps by Actuator for temperature flap left -V158- and Actuator for temperature flap right -V159-, go to «OUTPUT DIAGNOSTIC TEST MODE (DTM)»(/audi/s6/c5-1999-2004/remont/heated-glassdefoggers/#on-board-diagnostic-obd-hvac__output-diagnostic-test-mode-dtm).
2. To continue troubleshooting in (Scheme 89) (compressor was switched off during cooling performance test), go to (Scheme 90).

Scheme 81

1. To check and erase DTC memory of A/C system, go to «CHECK DTC MEMORY (FUNCTION 02)»(/audi/s6/c5-1999-2004/remont/heated-glassdefoggers/#on-board-diagnostic-obd-hvac) and «ERASE DTC MEMORY (FUNCTION 05) AND END OUTPUT (FUNCTION 06)»(/audi/s6/c5-1999-2004/remont/heated-glassdefoggers/#on-board-diagnostic-obd-hvac).
2. To test operation of A/C Clutch Relay -J44- and A/C clutch -N25-, go to «OUTPUT DIAGNOSTIC TEST MODE (DTM)»(/audi/s6/c5-1999-2004/remont/heated-glassdefoggers/#on-board-diagnostic-obd-hvac__output-diagnostic-test-mode-dtm).
3. For read measuring value block procedure, go to «READ MEASURING VALUE BLOCK (FUNCTION 08)»(/audi/s6/c5-1999-2004/remont/heated-glassdefoggers/#on-board-diagnostic-obd-hvac__read-measuring-value-block-function-08).
4. To continue troubleshooting in (Scheme 90) (compressor cut-off condition code 1), go to (Scheme 91).

Scheme 82

1. To indentify A/C pressure switch F129 terminals, see «A/C PRESSURE SWITCH -F129»(/audi/s6/c5-1999-2004/remont/automatic-hvac-system/#air-conditioning) .

Cooling performance checking (vehicles from model year 2002)

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. Connect VAG 1551 scan tool and press buttons -0- and -8-to insert AC/Heating Electronics" address word 08 and advance program until "Select function XX" appears on display. See «ON BOARD DIAGNOSTIC (OBD), INITIATING»(/audi/s6/c5-1999-2004/remont/heated-glassdefoggers/#on-board-diagnostic-obd-hvac) .
8. Initiate "Read Measuring Value Block" function 08 and select display group "001" for vehicles from model year 2002. See «MEASURING VALUE BLOCKS (VEHICLES FROM MODEL YEAR 2002)»(/audi/s6/c5-1999-2004/remont/heated-glassdefoggers/#on-board-diagnostic-obd-hvac) .
9. Check indication in display fields: Display field "2" shows 0% (compressor is switched off) Display field "4" shows, that the pressure in the refrigerant circuit measured at ambient temperature is the same or greater as the value shown in «AMBIENT TEMPERATURE AND PRESSURE (VEHICLES FROM MODEL YEAR 2002)»(/audi/s6/c5-1999-2004/remont/automatic-hvac-system/#air-conditioning) table.

AMBIENT TEMPERATURE AND PRESSURE (VEHICLES FROM MODEL YEAR 2002)

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 than the respective ambient temperature. If the displayed pressure is lower than in the table

1. Check measuring value of High Pressure Sensor -G65-. See «MEASURING VALUE BLOCKS (VEHICLES FROM MODEL YEAR 2002)»(/audi/s6/c5-1999-2004/remont/heated-glassdefoggers/#on-board-diagnostic-obd-hvac) and Electrical Testing, «TEST STEP 5 TO 9»(/audi/s6/c5-1999-2004/remont/heated-glassdefoggers/#on-board-diagnostic-obd-hvac) .
2. Not enough refrigerant in circuit, if no malfunction can be detected on high pressure sensor. Determine and eliminate the cause
3. Switch compressor on, for this select ECON mode on A/C control head -E87- (indicator light in ECON button does not light up).
4. Select temperature mode "Lo" (for driver's and passenger's side) on A/C Control Head -E87-.
5. Select air flow direction on A/C Control Head -E87- to "air from dash panel vents"
6. Select "Read Measuring Value Block" function 08, display group "001". See «MEASURING VALUE BLOCKS (VEHICLES FROM MODEL YEAR 2002)»(/audi/s6/c5-1999-2004/remont/heated-glassdefoggers/#on-board-diagnostic-obd-hvac) .
7. Check indication in display fields: A duty cycle greater than 30% is displayed in display field "2" (compressor is switched on, A/C Compressor Regulator Valve -N280- is activated or compressor is being driven via the A/C Clutch -N25-). A current greater than 0.3 A is displayed in display field "1" (current flows via A/C Compressor Regulator Valve -N280-, compressor is switched on) in vehicles with a compressor with A/C Compressor Regulator Valve -N280- In vehicles with a compressor with A/C Clutch -N25-, compressor is driven. A current greater than 0.1 A is displayed in display field "1", depending on version of A/C Control Head -E87- (current flows via A/C Clutch Relay -J44-, compressor is driven via the A/C Clutch -N25-). The shown pressure in display field "4" rises above the value with the compressor switched on.

Note. If display field "1" shows no or too little current on vehicles with A/C Compressor Regulator Valve -N280-, check: A/C Control Head -E87- activates A/C Compressor Regulator Valve -N280- so that the air temperature after evaporator reaches the specified value (approx. 2 to 5 C). A value greater than 75 % (0.55A) is displayed after vehicle start, depending on measured temperature, engine speed and vehicle electrical supply. As soon as the temperature measured by Evaporator Vent Temperature Sensor -G263- approaches the specified value, the activation is decreased and therefore compressor performance is reduced. The activation of A/C Compressor Regulator Valve -N280-. See Electrical Testing, TEST STEP 5 TO 9 , test step 6" In vehicles with a compressor with A/C Clutch -N25-, compressor is not being driven, check: The activation of A/C Clutch Relay -J44-. See Electrical Testing, TEST STEP 5 TO 9 , test step 7". 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. Determine and eliminate the cause.

1. Press button for "air recirculation" (symbol for "air recirculation" mode button is lit up).
2. Increase engine speed to 2000 RPM (timed period begins). Continuation of test
3. On vehicle with compressor using A/C Compressor Regulator Valve -N280-. See «NOTES FOR TEST STEP 27»(/audi/s6/c5-1999-2004/remont/automatic-hvac-system/#air-conditioning__compressor-with-ac-clutch-n25-removing) .
4. On vehicles with compressor with A/C Clutch -N25-, see «A/C SYSTEM, CHECKING AND TESTING»(/audi/s6/c5-1999-2004/remont/automatic-hvac-system/#air-conditioning) .

Scheme 83

1. Initiate "Read Measuring Value Block" function 08, and select display group "010" for vehicles from model year 2002. See «MEASURING VALUE BLOCKS (VEHICLES FROM MODEL YEAR 2002)»(/audi/s6/c5-1999-2004/remont/heated-glassdefoggers/#on-board-diagnostic-obd-hvac) .
2. Compare displayed measuring value (of Evaporator V Temperature Sensor -G263-) in display field "1" with values in diagram.

1. Measured air temperature of Evaporator Vent Temperature Sensor -G263
2. Ambient temperature
3. 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 attained, 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 . 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 MEASURING VALUE BLOCKS (VEHICLES FROM MODEL YEAR 2002) . Also see Electrical testing, TEST STEP 1 TO 4 , test step 2. The operation of the air conditioning is recognizable, for example, 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).

1. 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" can be maximum 3 L 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" 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 electrical testing, TEST STEP 1 TO 4 , test step 2. If the measuring value in display group "009" display fields "3" or "4" 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 malfunction at temperature raise after evaporator". See IDENTIFYING MALFUNCTIONS AT TEMPERATURE INCREASE BEHIND CONDENSER . The air temperature of the center dash panel vents can be measured e.g. using the VAG 1362 mini tester. The measuring value of Sender for outlet temperature, floor outlet -G192- is shown in display group "009" display field "1". This sensor shows 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, this sensor can also be checked in this test.

Scheme 84

1. For read measuring value block information, see «READ MEASURING VALUE BLOCK (FUNCTION 08)»(/audi/s6/c5-1999-2004/remont/heated-glassdefoggers/#on-board-diagnostic-obd-hvac__read-measuring-value-block-function-08) . For vehicles from model year 2002, see «MEASURING VALUE BLOCKS (VEHICLES FROM MODEL YEAR 2002)»(/audi/s6/c5-1999-2004/remont/heated-glassdefoggers/#on-board-diagnostic-obd-hvac) .
2. To check and erase DTC memory in A/C system, see «CHECK DTC MEMORY (FUNCTION 02)»(/audi/s6/c5-1999-2004/remont/heated-glassdefoggers/#on-board-diagnostic-obd-hvac) and «ERASE DTC MEMORY (FUNCTION 05) AND END OUTPUT (FUNCTION 06)»(/audi/s6/c5-1999-2004/remont/heated-glassdefoggers/#on-board-diagnostic-obd-hvac) .

Scheme 85

1. For read measuring value block information, see «READ MEASURING VALUE BLOCK (FUNCTION 08)»(/audi/s6/c5-1999-2004/remont/heated-glassdefoggers/#on-board-diagnostic-obd-hvac__read-measuring-value-block-function-08) . For vehicles from model year 2002, see «MEASURING VALUE BLOCKS (VEHICLES FROM MODEL YEAR 2002)»(/audi/s6/c5-1999-2004/remont/heated-glassdefoggers/#on-board-diagnostic-obd-hvac) .
2. To check activation of Coolant Fan -V7-, carry out «OUTPUT DIAGNOSTIC TEST MODE (DTM)»(/audi/s6/c5-1999-2004/remont/heated-glassdefoggers/#on-board-diagnostic-obd-hvac__output-diagnostic-test-mode-dtm) .

Notes

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. See «MEASURING VALUE BLOCKS (VEHICLES FROM MODEL YEAR 2002)»(/audi/s6/c5-1999-2004/remont/heated-glassdefoggers/#on-board-diagnostic-obd-hvac) , (display group "001", display field "3"). The A/C Control Head -E87- calculates the pressure in the refrigerant circuit.
4. When the duty cycle is less 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 15% (correspond 2.6 bar absolute pressure) or less 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): 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). As soon as the coolant temperature reaches 115° C (at 118 ° C compressor is switched completely).
6. Additional notes on pressures in the refrigerant circuit. See «MEASURING VALUE BLOCKS (VEHICLES FROM MODEL YEAR 2002)»(/audi/s6/c5-1999-2004/remont/heated-glassdefoggers/#on-board-diagnostic-obd-hvac) , display group 001.

Scheme 86

1. To check activation of Actuator for temperature flap left -V158- and Actuator for temperature flap right -V159-, carry out «OUTPUT DIAGNOSTIC TEST MODE (DTM)»(/audi/s6/c5-1999-2004/remont/heated-glassdefoggers/#on-board-diagnostic-obd-hvac__output-diagnostic-test-mode-dtm) .
2. To check position of temperature flaps and actuator levers of Actuator for temperature flap left -V158- and Actuator for temperature flap right -V159-, go to «ACTUATOR FOR TEMPERATURE FLAP LEFT -V158-, REMOVING AND INSTALLING»(/audi/s6/c5-1999-2004/remont/automatic-hvac-system/#air-conditioning) and «ACTUATOR FOR TEMPERATURE FLAP RIGHT -V159-, REMOVING AND INSTALLING»(/audi/s6/c5-1999-2004/remont/automatic-hvac-system/#air-conditioning__actuator-for-temperature-flap-right-v159) .

Continuation for vehicles with compressor using A/C Clutch -N25

1. Close center dash panel vent (the "left" and "right" dash panel vents stay open).
2. Initiate "Read Measuring Value Block" function 08, and select display group "009" for vehicles from model year 2002. See «MEASURING VALUE BLOCKS (VEHICLES FROM MODEL YEAR 2002)»(/audi/s6/c5-1999-2004/remont/heated-glassdefoggers/#on-board-diagnostic-obd-hvac) .
3. Compare displayed measuring values (of -G150- and -G151-) in display fields "3" and "4" with values in diagram.

Scheme 87

A - The measured air temperature of Left Vent Temperature Sensor -G150- and Right Vent Temperature Sensor -G151

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, compare displayed measuring values in display group "009" display fields "3" and "4" with each other.

1. If measuring values in display fields "3" or "4" differ only slightly from each other, carry out «IDENTIFYING MALFUNCTIONS IF SPECIFIED VALUES ARE NOT OBTAINED»(/audi/s6/c5-1999-2004/remont/automatic-hvac-system/#air-conditioning) . If the measuring value of one sensor is substantially greater than the measuring value of the other sensor: Check Left Vent Temperature Sensor -G150- and Right Vent Temperature Sensor -G151- for correct installation and check sensor. See «ELECTRICAL TESTING (VEHICLES FROM MODEL YEAR 2002)»(/audi/s6/c5-1999-2004/remont/heated-glassdefoggers/#on-board-diagnostic-obd-hvac__electrical-testing-vehicles-from-model-year) , test step 2". Check operation of Actuator for temperature flap left -V158- and Actuator for temperature flap right -V159- and actuator lever. If no malfunction is recognized on -G150- and -G151-, carry out "Identifying malfunction at temperature increase after evaporator". See «IDENTIFYING MALFUNCTIONS AT TEMPERATURE INCREASE BEHIND CONDENSER»(/audi/s6/c5-1999-2004/remont/automatic-hvac-system/#air-conditioning) .
2. The operation of the air conditioning is recognizable, e.g. the refrigerant pipe on the low pressure side (big line) cools off.
3. The air temperature of the center dash panel vents can be measured e.g. using the VAG 1362 mini tester.
4. The measuring value of Sender for outlet temperature, floor outlet -G192- is shown in display group "009" display field "1". This sensor shows 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, this sensor can also be checked in this test.

Scheme 88

1. For read measuring value information, see «READ MEASURING VALUE BLOCK (FUNCTION 08)»(/audi/s6/c5-1999-2004/remont/heated-glassdefoggers/#on-board-diagnostic-obd-hvac__read-measuring-value-block-function-08) and «MEASURING VALUE BLOCKS (VEHICLES FROM MODEL YEAR 2002)»(/audi/s6/c5-1999-2004/remont/heated-glassdefoggers/#on-board-diagnostic-obd-hvac) .
2. To check and erase A/C system memory, see «CHECK DTC MEMORY (FUNCTION 02)»(/audi/s6/c5-1999-2004/remont/heated-glassdefoggers/#on-board-diagnostic-obd-hvac) and «ERASE DTC MEMORY (FUNCTION 05) AND END OUTPUT (FUNCTION 06)»(/audi/s6/c5-1999-2004/remont/heated-glassdefoggers/#on-board-diagnostic-obd-hvac) .
3. For read measuring value block group 002, see «DISPLAY GROUP 002: LAST FOUR COMPRESSOR CUT-OFF CONDITIONS»(/audi/s6/c5-1999-2004/remont/heated-glassdefoggers/#on-board-diagnostic-obd-hvac) .

Scheme 89

1. For Read Measuring Value Block, display group 001 display field 4, see «DISPLAY GROUP 001: A/C COMPRESSOR REGULATOR VALVE -N280-, A/C CLUTCH RELAY -J44- AND HIGH PRESSURE SENSOR -G65»(/audi/s6/c5-1999-2004/remont/heated-glassdefoggers/#on-board-diagnostic-obd-hvac) .
2. For Read Measuring Value Block, display group 014, see «DISPLAY GROUP 014: COOLANT FAN -V7- ACTIVATION»(/audi/s6/c5-1999-2004/remont/heated-glassdefoggers/#on-board-diagnostic-obd-hvac) .
3. To check activation of Coolant Fan -V7-, go to «OUTPUT DIAGNOSTIC TEST MODE (DTM)»(/audi/s6/c5-1999-2004/remont/heated-glassdefoggers/#on-board-diagnostic-obd-hvac__output-diagnostic-test-mode-dtm) .

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 ( «MEASURING VALUE BLOCKS (VEHICLES FROM MODEL YEAR 2002)»(/audi/s6/c5-1999-2004/remont/heated-glassdefoggers/#on-board-diagnostic-obd-hvac) , display group "001", display field "3"). The A/C Control Head -E87- calculates the pressure in the refrigerant circuit.
4. When the duty cycle is less 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 15% (correspond 2.6 bar absolute pressure) or less than 48% (corresponds to 16 bar absolute pressure).
5. Additional notes on pressures in the refrigerant circuit, see «MEASURING VALUE BLOCKS (VEHICLES FROM MODEL YEAR 2002)»(/audi/s6/c5-1999-2004/remont/heated-glassdefoggers/#on-board-diagnostic-obd-hvac) , display group 001.

Identifying malfunctions at temperature increase behind condenser

1. To check activation of Actuator for temperature flap left -V158- and Actuator for temperature flap right -V159-, carry out «OUTPUT DIAGNOSTIC TEST MODE (DTM)»(/audi/s6/c5-1999-2004/remont/heated-glassdefoggers/#on-board-diagnostic-obd-hvac__output-diagnostic-test-mode-dtm) .
2. To 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/s6/c5-1999-2004/remont/automatic-hvac-system/#air-conditioning) and «ACTUATOR FOR TEMPERATURE FLAP RIGHT -V159-, REMOVING AND INSTALLING»(/audi/s6/c5-1999-2004/remont/automatic-hvac-system/#air-conditioning__actuator-for-temperature-flap-right-v159) .

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.

Scheme 90

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 A/C SYSTEM, SAFETY PRECAUTIONS .

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

Use high pressure service valve for checking system pressures.

Test requirements

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 VAG 1551 scan tool and eliminate/repair any malfunctions indicated (not affecting A/C system)
5. All air distribution flaps reach end positions Engine at normal operating temperature
6. Evaporator housing and heater box do not leak air (draw in secondary air) at high fresh air blower speed
7. Outside (ambient) temperature must be between 15-45° C (59-113° F)
8. 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 clutch is switched on)

1. Fresh air blower -V2- runs
2. Coolant fan -Ml- 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 «ON BOARD DIAGNOSTIC (OBD), INITIATING»(/audi/s6/c5-1999-2004/remont/heated-glassdefoggers/#on-board-diagnostic-obd-hvac) .

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 «A/C SYSTEM, QUICK COUPLING CONNECTIONS»(/audi/s6/c5-1999-2004/remont/automatic-hvac-system/#air-conditioning__ac-system-quick-coupling-connections) .
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.

TEMPERATURE AND REFRIGERANT SYSTEM PRESSURE

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
3. Check actuation of coolant fan -V7- according to wiring diagram.
4. Check for pinched, kinked or damaged refrigerant lines/hoses. If no problems are found
5. Discharge refrigerant system. See «A/C REFRIGERANT SYSTEM (R-134A), DISCHARGING»(/audi/s6/c5-1999-2004/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/s6/c5-1999-2004/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.

Note. If A/C clutch -N25- is not engaged, check voltage supply to A/C clutch according to wiring diagram. If voltage is OK, repair (replace) A/C clutch. See A/C CLUTCH -N25-, SERVICING (DENSO COMPRESSOR) .

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). NOTE: Switching pressure specifications of A/C refrigerant pressure switch -F129-. See «A/C PRESSURE SWITCH -F129»(/audi/s6/c5-1999-2004/remont/automatic-hvac-system/#air-conditioning) .

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. See A/C SYSTEM, SAFETY PRECAUTIONS when discharging an 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.

Scheme 91

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. See «A/C REFRIGERANT SYSTEM (R-134A), DISCHARGING»(/audi/s6/c5-1999-2004/remont/automatic-hvac-system/#air-conditioning__ac-refrigerant-system-r-134a-discharging) .
2. After emptying A/C system, disconnect power supply from A/C clutch -N25- (e.g. disconnect harness connector from A/C pressure switch -F129-) to prevent accidental compressor operation with A/C system discharged.

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. See A/C SYSTEM, 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 A/C refrigerant oil capacities. See «A/C REFRIGERANT R-134A AND REFRIGERANT OIL (PAG), CAPACITIES»(/audi/s6/c5-1999-2004/remont/automatic-hvac-system/#air-conditioning) .
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 refrigerant system, replacing components. See «A/C SYSTEM, REPLACING COMPONENTS»(/audi/s6/c5-1999-2004/remont/automatic-hvac-system/#air-conditioning__ac-system-replacing-components) .

A/C refrigerant system, servicing

Note. No refrigerant must be added to the refrigerant circuit (discharge, evacuate and recharge refrigerant circuit). See A/C REFRIGERANT SYSTEM (R-134A), DISCHARGING . Replacement compressors contain the total amount of refrigerant oil to be filled into the refrigerant circuit: Service work on refrigerant circuit, see REFRIGERANT CIRCUIT, SERVICING . Checking cooling performance, see A/C SYSTEM COOLING PERFORMANCE, TESTING . Checking pressures in refrigerant circuit. Starting September 1998, there was a running change in production from the version "1" air conditioner to the version "2" air conditioner. See AIR CONDITIONING CHANGES . Up to model year 2001 only compressors with A/C Clutch -N25- were installed. As of model year 2002 compressors with A/C Clutch -N25- or with A/C Compressor Regulator Valve -N280- are installed depending on engine type. See COMPRESSOR, WITH A/C CLUTCH -N25 and COMPRESSOR, WITH A/C COMPRESSOR REGULATOR VALVE -N280 . When installing refrigerant lines/hoses and retaining bracket, make sure there is a sufficient gap between belt, bracket and belt pulley. Zexel-, Sanden- and Denso-compressors require different refrigerant oils: See A/C REFRIGERANT R-134A AND REFRIGERANT OIL (PAG), CAPACITIES . Different filling capacities for refrigerant oil depending on compressor type and version. See A/C REFRIGERANT R-134A AND REFRIGERANT OIL (PAG), CAPACITIES . The suggested diameters of the O-rings and gaskets and the tightening torques pertain also the bolts of the refrigerant lines or hoses between the separate components. Only install O-rings that are approved for Refrigerant R134a (currently red, light purple and dark purple). Adapter for service station to connect to refrigerant circuit. All service and repair work not covered in this Repair Manual.

1. Always refer to safety measures. See «A/C SYSTEM, SAFETY PRECAUTIONS»(/audi/s6/c5-1999-2004/remont/automatic-hvac-system/#air-conditioning__ac-system-safety-precautions) .
2. 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.
3. In the engine compartment there is a sticker with data on the capacity and the type of refrigerant. The R134a refrigerant capacity depends on the version of the following components
4. Condenser
5. Evaporator (installed in air conditioner)
6. Restrictor (orifice tube) Characteristics of the refrigerant system
7. Compressor manufacturer "Zexel" or "Denso"
8. Restrictor (orifice tube)
9. Accumulator

Determining dimensions of flat tubes from condenser

Note. As of March 1999, there will be a running change in production to a condenser with smaller flat tubes.

For condensers with flat tube dimensions A = 20 mm; B = 3.0 mm, more refrigerant must be added than for condensers with flat tube measurements -A- = 18 mm or 16 mm; -B- = 1.7 mm

Capacities: See CAPACITIES FOR THE AUDI A6 .

Scheme 92

Note. If the condenser is replaced, the flat tube dimensions must be noted. If a condenser with other dimensions is installed, information plate -A- with the capacity data for refrigerant R134a must also be replaced, or the old capacity data must be removed and the new capacity entered using a waterproof pen.

Scheme 93

1. In the period from week 36 to week 44, 1998, there was a running change in production from the version 1 air conditioner to the version 2 air conditioner. The two versions can be differentiated by specific characteristics. See «AIR CONDITIONING CHANGES»(/audi/s6/c5-1999-2004/remont/automatic-hvac-system/#air-conditioning) .
2. On vehicles with the version 2 air conditioner, a little less refrigerant needs to be added than in the version 1 air conditioner. See «CAPACITIES FOR THE AUDI A6»(/audi/s6/c5-1999-2004/remont/automatic-hvac-system/#air-conditioning) .

Restrictor version

1. Since November 1997, restrictors with a smaller hole have been installed in production, and are colored (at first yellow) so that they can be identified.
2. On vehicles in which the colored restrictors are installed, somewhat more refrigerant has to be added. See «CAPACITIES FOR THE AUDI A6»(/audi/s6/c5-1999-2004/remont/automatic-hvac-system/#air-conditioning) .

Scheme 94

Scheme 95

1. To identifying dimensions of flat tubes on condensors, see «DETERMINING DIMENSIONS OF FLAT TUBES FROM CONDENSER»(/audi/s6/c5-1999-2004/remont/automatic-hvac-system/#air-conditioning__determining-dimensions-of-flat-tubes-from) .

Note. Since November 1997, restrictors with a modified hole (colored) have been installed during production. For vehicles in which modified restrictors are installed, the capacity was increased by 50 grams. In order to differentiate the two restrictor versions, the restrictor with the smaller hole (restricted portion) is colored (for the meantime, yellow). lf a colored restrictor is installed in a vehicle in which the previous restrictor had not been colored, 50 grams more refrigerant should be added. In addition, the capacity specification on the information plate affixed in the vehicle should be checked and corrected if necessary, or the original information plate should be replaced with a information plate indicating the correct capacity (affix on top of previous one). There was a running change in production from the version 1 air conditioner to the version 2 air conditioner starting in August/September 1998. Since the evaporator was also modified along with the air conditioner, the capacity could be reduced. The two air conditioner versions can be differentiated via specific characteristics. See AIR CONDITIONING CHANGES . For the Audi A6, different compressors are installed depending on the engine and production time.

Scheme 96

1. To identifying dimensions of flat tubes on condensors, see «DETERMINING DIMENSIONS OF FLAT TUBES FROM CONDENSER»(/audi/s6/c5-1999-2004/remont/automatic-hvac-system/#air-conditioning__determining-dimensions-of-flat-tubes-from) .

Note. Since November 1997, restrictors with a modified hole (colored) have been installed during production. For vehicles in which modified restrictors are installed, the capacity was increased by 50 grams. In order to differentiate the two restrictor versions, the restrictor with the smaller hole (restricted portion) is colored (for the meantime, yellow). There was a running change in production from the version 1 air conditioner to the version 2 air conditioner starting in August/September1998. Since the evaporator was also modified along with the air conditioner, the capacity could be reduced. The two air conditioner versions can be differentiated via specific characteristics. See AIR CONDITIONING CHANGES . For the Audi A6, different compressors are installed depending on the engine and production time. In March 1999, there was a running change in production from condensers with flat tube dimensions 20 mm x 3 mm (part number4BO 260 401 and indices, "F" or "E") to condensers with flat tube dimensions 18 mm x 1.7 mm (part number4BO 260 401 and indices, "H" or "J"). If a condenser with different flat tube dimensions is installed, the capacity specification on the information plate must be corrected or, if necessary, a corrected information plate must be affixed over the existing information plate. The part number is on a sticker that is affixed to the underside of the condenser.

Scheme 97

1. To identifying dimensions of flat tubes on condensors, see «DETERMINING DIMENSIONS OF FLAT TUBES FROM CONDENSER»(/audi/s6/c5-1999-2004/remont/automatic-hvac-system/#air-conditioning__determining-dimensions-of-flat-tubes-from) .

Note. Since November 1997, restrictors with a modified hole (colored) have been installed during production. In order to differentiate the two restrictor versions, the restrictor with the smaller hole (restricted portion) is colored (for the meantime, yellow). For the Audi A6 with 8-cyl. engine, only "Denso" compressors are installed. There was a running change in production from the version 1 air conditioner to the version 2 air conditioner starting in August/September1998. Since the evaporator was also modified along with the air conditioner, the capacity could be reduced. The two air conditioner versions can be differentiated via specific characteristics. See AIR CONDITIONING CHANGES . For vehicles with 8-cyl. engines, only version "2" air conditioners are installed, different condensers are also installed in these vehicles. In March 1999 (as of production start for USA vehicles) production was changed to condensers with part number 4B3 260 401 C. If the installed condenser is replaced with a condenser with a different part number, the capacity specification on the information plate must be corrected or, if necessary, a corrected information plate must be affixed over the existing information plate. The part number is on a sticker that is affixed to the underside of the condenser. 4 For vehicles with 8-cyl. engines, different condensers are installed. In vehicles intended for the USA, only condensers with part number 4B3 260 401 C are installed.

Released refrigerant oil (PAG)

Note. The oils for refrigerant R12 are not compatible with refrigerant R134a. The oil is special and only for refrigerant R134a cycle. It can no longer be obtained under the name "refrigerant machine oil." Refrigerant oils are specific for each compressor. Only use specified refrigerant oil in the refrigerant system. 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.

AUDI 6 PAG OIL CAPACITY

Note. The refrigerant oil capacity is given for a complete system with the Denso compressor. Replacement compressors supplied by the Parts department are filled with an amount equal to the capacity of the entire system. See A/C SYSTEM, REPLACING COMPONENTS . When A/C is switched on for the first time, the refrigerant oil is distributed throughout the entire system. When replacing A/C system components, add appropriate amount of refrigerant oil to component. See A/C SYSTEM, REPLACING COMPONENTS .

Vehicles with compressors with A/C clutch -N25

HP = High pressure side

LP = Low pressure side

Note. The replacement compressor contains the total amount of refrigerant oil to be filled into the refrigerant circuit (250 cm 3 ).

Note. The following list refers to items in (Scheme 108).

1. Compressor ("Zexel" or "Denso") O-ring gasket (for all refrigerant lines on "Zexel" compressor): Low pressures connection: 17.2 mm x 1.8 mm High pressure connection: 14.0 mm x 1.8 mm Remove refrigerant lines from "Denso" compressor (pertaining O-rings and tightening torques for bolts, see «REFRIGERANT LINES FROM DENSO COMPRESSOR (WITH A/C CLUTCH -N25-), REMOVING AND INSTALLING»(/audi/s6/c5-1999-2004/remont/automatic-hvac-system/#air-conditioning__refrigerant-lines-from-denso-compressor-with) ). Removing and installing, see «COMPRESSOR (WITH A/C CLUTCH -N25-), REMOVING AND INSTALLING»(/audi/s6/c5-1999-2004/remont/automatic-hvac-system/#air-conditioning__compressor-with-ac-clutch-n25-removing) . NOTE: Allocation of different compressors, see «REFRIGERANT CIRCUIT, SERVICING»(/audi/s6/c5-1999-2004/remont/automatic-hvac-system/#air-conditioning__refrigerant-circuit-servicing) . The piston stroke of the compressor is variable, the stroke adjust itself depending on the required cooling performance. If a new compressor has been installed or new refrigerant oil has been put into the compressor (for example, after blowing through the A/C system and discharging the compressor via the oil drain plug), the compressor must be turned by hand approx. 10 revolutions. This ensures that the compressor is not damaged when activated.
2. A/C clutch -N25- Servicing refrigerant system, see «REFRIGERANT CIRCUIT, SERVICING»(/audi/s6/c5-1999-2004/remont/automatic-hvac-system/#air-conditioning__refrigerant-circuit-servicing) . NOTE: Ribbed belt, removing and installing. See appropriate ENGINE MECHANICAL article. Mark running direction of ribbed belt before removing, reversed running direction may lead to belt damage.
3. Oil drain plug Tightening torques: 30 Nm ("Denso"-compressor) NOTE: The Denso compressor drain plug is installed with an ordinary sealing ring instead of an O-ring. This must be always be replaced. Only remove the plug to drain the refrigerant oil. Different refrigerant oils between Zexel and Denso compressors.
4. High pressure relief valve O-ring seal: 8.8 mm x 1.9 mm. Tightening torque: 10 Nm WARNING: The connection does not have a Schrader valve to prevent gas from escaping if the pressure relief valve is removed. Only remove the pressure relief valve when the refrigerant has been discharged from the A/C system.
5. Circuit with valve
6. A/C Pressure Switch -F129-/High Pressure Switch -G65- A/C Pressure Switch -F129-, function, removing and installing, see «A/C PRESSURE SWITCH -F129»(/audi/s6/c5-1999-2004/remont/automatic-hvac-system/#air-conditioning) . High Pressure Switch -G65-, removing and installing, see «HIGH PRESSURE SENSOR -G65-, REMOVING AND INSTALLING»(/audi/s6/c5-1999-2004/remont/automatic-hvac-system/#air-conditioning__high-pressure-sensor-g65-removing-and) High Pressure Switch -G65-, checking signal. See Electrical Testing, «TEST STEP 5 TO 9»(/audi/s6/c5-1999-2004/remont/heated-glassdefoggers/#on-board-diagnostic-obd-hvac) . NOTE: A/C Pressure Switch -F129- were installed on vehicles up to model year 2001. On vehicles from model year 2002 High Pressure Sensor -G65- is installed.
7. Condenser O-ring seals replacing, see «REFRIGERANT LINES FOR CONDENSER, REMOVING AND INSTALLING»(/audi/s6/c5-1999-2004/remont/automatic-hvac-system/#air-conditioning__refrigerant-lines-for-condenser-removing-and) Refrigerant lines, removing and installing, see «REFRIGERANT LINES FOR CONDENSER, REMOVING AND INSTALLING»(/audi/s6/c5-1999-2004/remont/automatic-hvac-system/#air-conditioning__refrigerant-lines-for-condenser-removing-and) Condenser removing and installing, see «CONDENSER, REMOVING AND INSTALLING»(/audi/s6/c5-1999-2004/remont/automatic-hvac-system/#air-conditioning) . Different refrigerant R134a capacities depending on condenser, see «CAPACITIES»(/audi/s6/c5-1999-2004/remont/automatic-hvac-system/#air-conditioning__capacities)
8. Bolts in refrigerant line O-ring seal: 10.8 mm x 1.8 mm. Tightening torque: 15 Nm
9. Closing cap With seal, always reinstall after using service valve.
10. Service connection High pressure side. For measuring, discharging and recharging.
11. Restrictor O-ring seal: 7.5 mm x 1.5 mm. Installed in bolt position 8. Removing and installing, see «RESTRICTOR, REMOVING AND INSTALLING»(/audi/s6/c5-1999-2004/remont/automatic-hvac-system/#air-conditioning) . Always replace restrictor (together with O-ring).
12. Evaporator Refrigerant lines, removing and installing, see «REFRIGERANT LINES ON EVAPORATOR, DISCONNECTING AND CONNECTING»(/audi/s6/c5-1999-2004/remont/automatic-hvac-system/#air-conditioning) Removing and installing air conditioner unit, see «COMPLETE AIR CONDITIONER UNIT, REMOVING AND INSTALLING»(/audi/s6/c5-1999-2004/remont/automatic-hvac-system/#air-conditioning__complete-air-conditioner-unit-removing-and) . Disassembling and assembling air conditioner, see «A/C UNIT, DISASSEMBLING AND ASSEMBLING»(/audi/s6/c5-1999-2004/remont/automatic-hvac-system/#air-conditioning__ac-unit-disassembling-and-assembling) Different versions, version "2" width of evaporator is 32 mm less than in version "1". From version "2", evaporator can only be replaced together with air distributor housing.
13. Service connection Low pressure side For service-station for measuring and discharging.
14. Closing cap With seal, always reinstall after using service valve.
15. Catch reservoir Removing and installing, see «CONDENSER, REMOVING AND INSTALLING»(/audi/s6/c5-1999-2004/remont/automatic-hvac-system/#air-conditioning__condenser-removing-and-installing) .

Scheme 98

Refrigerant lines from Denso compressor (with A/C clutch -N25-), removing and installing

1. Discharge refrigerant circuit. See «A/C REFRIGERANT SYSTEM (R-134A), DISCHARGING»(/audi/s6/c5-1999-2004/remont/automatic-hvac-system/#air-conditioning__ac-refrigerant-system-r-134a-discharging) .
2. Remove bolts -A- and -B- (tightening torque 25 Nm).
3. O-Ring-seals-C- (23.8mm x 2.4mm) and -D- (11.1mm x 1.8mm) replacing.

Scheme 99

Note. There may be different methods for installing the refrigerant lines to the connecting flange. Do not use the O-rings from the shipping caps that are installed on the connections when installing lines. Seal off all open refrigerant lines and connections on the compressor.

Denso compressor, removing and installing from bracket (8 cyl. engine with A/C clutch - N25-)

Note. Compressor bracket from engine, removing and installing. See appropriate ENGINE MECHANICAL article. Do not discharge the refrigerant circuit. The compressor can be removed without opening refrigerant lines.

1. Lock carrier, moving-into service position: See «LOCK CARRIER, SERVICE POSITION»(/audi/s6/c5-1999-2004/remont/exterior-body-panels/#body-front__lock-carrier-service-position) .

Removing

1. Release tension on ribbed belt: See appropriate ENGINE MECHANICAL article.
2. Remove screws -A- and -B-. (Scheme 110)

Scheme 100

Note. The high pressure line is connected on the left side of condenser in this vehicle, therefore please note the following: After removal, secure compressor on left longmember, do not let it hang on refrigerant line. When removing engine, secure compressor together with condenser on right longmember after removing lock carrier.

Scheme 101

1. Observe proper seating of centering pins -C- when installing compressor.
2. Tighten bolts -A- and -B- to 25 Nm.

Compressor (with A/C Clutch -N25-), removing and installing

1. Discharge refrigerant circuit. See «A/C REFRIGERANT SYSTEM (R-134A), DISCHARGING»(/audi/s6/c5-1999-2004/remont/automatic-hvac-system/#air-conditioning__ac-refrigerant-system-r-134a-discharging) .
2. Disconnect refrigerant lines from compressor. See «REFRIGERANT LINES FROM DENSO COMPRESSOR (WITH A/C CLUTCH -N25-), REMOVING AND INSTALLING»(/audi/s6/c5-1999-2004/remont/automatic-hvac-system/#air-conditioning__refrigerant-lines-from-denso-compressor-with) .
3. Remove compressor from bracket. See «REFRIGERANT CIRCUIT, SERVICING»(/audi/s6/c5-1999-2004/remont/automatic-hvac-system/#air-conditioning__refrigerant-circuit-servicing) .

Note. 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 and discharging compressor via oil drain plug), the compressor must be turned manually approx. 10 revolutions. This ensures that the compressor is not damaged when activated. When operating the compressor for the first time: Start engine with system switched off (operating mode "OFF"). Wait until idle speed has stabilized. Switch compressor on and allow it to run at least 10 minutes with engine idling. Ribbed belt, removing and installing (6 and 8 cylinder engine).

See appropriate ENGINE MECHANICAL article.

Vehicles with compressor drive via a belt

Note. The compressor can be removed without opening refrigerant lines. Do not discharge the A/C system, and do not disconnect refrigerant lines of compressor. After removing, secure A/C compressor to longmember (i.e. with wire) Do not hang on refrigerant lines. Mark the running direction of the ribbed belt with a crayon or 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 variant (right or left side of engine, 6 cyl. engines).

Compressor (installed on right side of engine), removing and installing from bracket

Note. The compressor is installed (for example, on a 1.9L Diesel engine, not for USA) on right hand side of the engine. Do not loosen refrigerant lines and clamps -D-. (Scheme 112)

1. Remove noise insulation: See «NOISE INSULATION PANEL, ASSEMBLY OVERVIEW»(/audi/s6/c5-1999-2004/remont/exterior-body-panels/#body-front__noise-insulation-panel-assembly-overview).
2. Bring lock carrier into service-position: See «NOISE INSULATION PANEL, ASSEMBLY OVERVIEW»(/audi/s6/c5-1999-2004/remont/exterior-body-panels/#body-front__noise-insulation-panel-assembly-overview).
3. Release ribbed belt and remove. See appropriate ENGINE MECHANICAL article.
4. Remove screws -A- (25 Nm). (Scheme 112)

Scheme 102

Note. Install one washer -B- on each bolt -A-. (Scheme 112) Before fastening the compressor, check that both bushings -C- in bracket or compressor are seated correctly. After fastening the compressor, check installation position of refrigerant lines -A-, lines must be engaged in bracket -B-. (Scheme 113) After fastening the compressor, check the refrigerant lines and brackets for enough distance to other components.

Compressor (installed on left side of engine), removing and installing from bracket

Note. For example, the compressor is installed on the 2.0L gas engine (left side of engine). Do not loosen refrigerant lines and pertaining clamp. The illustration shows the compressor on a 4 cyl. gas engine. On other engine variants the arrangement deviates only slightly from this illustration (for example, different refrigerant lines).

See appropriate ENGINE MECHANICAL article.

1. Remove noise insulation: See «NOISE INSULATION PANEL, ASSEMBLY OVERVIEW»(/audi/s6/c5-1999-2004/remont/exterior-body-panels/#body-front__noise-insulation-panel-assembly-overview) .
2. Bring lock carrier into service position: See «LOCK CARRIER, SERVICE POSITION»(/audi/s6/c5-1999-2004/remont/exterior-body-panels/#body-front__lock-carrier-service-position) .

1. Remove oil filter. Protect sealing surface from damage (only on vehicles with 6 cyl. gas engine)

See appropriate ENGINE MECHANICAL article.

1. Release ribbed belt and remove.

See appropriate ENGINE MECHANICAL article.

1. Remove bolts -A- (25 Nm).

Scheme 103

Note. Install one washer -B- on each bolt -A-. (Scheme 114) Before fastening the compressor, check that both bushings -C- in bracket or compressor are seated correctly. After fastening the compressor, check installation position of refrigerant lines -A-, lines must be engaged in bracket -B-. (Scheme 115) After fastening the compressor, check the refrigerant lines and pertaining bracket as well and there is sufficient gap to other components. On vehicles with 6 cylinder engines make sure there is enough space between belt, bracket and belt pulley.

Scheme 104

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

Note. The compressor is driven by a toothed gear that is part of drive shaft -B-. (Scheme 116) Removing and installing compressor bracket to engine. See appropriate ENGINE MECHANICAL article. To remove the compressor on vehicles with an 8-cyl. engine, refrigerant circuit must be drained and then both refrigerant lines must be disconnected from compressor. See REFRIGERANT LINES ON COMPRESSOR, DISCONNECTING AND CONNECTING (COMPRESSOR WITH A/C COMPRESSOR REGULATOR VALVE -N280-). Air conditioning system with refrigerant R134a Removing and installing compressor to bracket. See COMPRESSOR (WITH A/C COMPRESSOR REGULATOR VALVE -N280-), REMOVING AND INSTALLING (IN A VEHICLES WITH 6 CYL. ENGINE).

Belt pulley, replacing

Note. Different versions of the pulley are installed, depending on compressor type and engine version. Pulley, removing from compressor and re-installing, see PULLEY, REMOVING FROM COMPRESSOR AND INSTALLING

Note. The following list refers to items in (Scheme 117).

1. Bolt Replace Tightening torque 20 Nm Loosening and tightening, see «PULLEY, REMOVING FROM COMPRESSOR AND INSTALLING»(/audi/s6/c5-1999-2004/remont/automatic-hvac-system/#air-conditioning__pulley-removing-from-compressor-and-installing)
2. Drive plate Different versions Removing and installing, see «PULLEY, REMOVING FROM COMPRESSOR AND INSTALLING»(/audi/s6/c5-1999-2004/remont/automatic-hvac-system/#air-conditioning__pulley-removing-from-compressor-and-installing) Triggers with torque too high (for example, compressor produces friction)
3. Snap ring Replace Install on proper side (level side to compressor) Removing and installing, see «PULLEY, REMOVING FROM COMPRESSOR AND INSTALLING»(/audi/s6/c5-1999-2004/remont/automatic-hvac-system/#air-conditioning__pulley-removing-from-compressor-and-installing)
4. Belt pulley Rubber element of pulley triggers 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 INSTALLING»(/audi/s6/c5-1999-2004/remont/automatic-hvac-system/#air-conditioning__pulley-removing-from-compressor-and-installing) NOTE: Under certain conditions (for example, 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.

Scheme 105

Pulley, removing from compressor and installing

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 WITH A/C COMPRESSOR REGULATOR VALVE -N280-, REMOVING AND INSTALLING FROM BRACKET . The compressor can be removed and installed from the bracket without opening the refrigerant lines. See COMPRESSOR WITH A/C COMPRESSOR REGULATOR VALVE -N280-, REMOVING AND INSTALLING FROM BRACKET . 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).

1. Remove noise insulation: See «NOISE INSULATION PANEL, ASSEMBLY OVERVIEW»(/audi/s6/c5-1999-2004/remont/exterior-body-panels/#body-front__noise-insulation-panel-assembly-overview) .

1. Bring the lock carrier into service position: See «LOCK CARRIER, SERVICE POSITION»(/audi/s6/c5-1999-2004/remont/exterior-body-panels/#body-front__lock-carrier-service-position) .

1. Release tension on ribbed belt and remove it.

See appropriate ENGINE MECHANICAL article.

1. Remove bolt -A- (tightening torque 20 Nm). (Scheme 118)

Scheme 106

Note. If pulley cannot be removed with compressor installed, remove compressor from engine. See COMPRESSOR WITH A/C COMPRESSOR REGULATOR VALVE -N280-, REMOVING AND INSTALLING FROM BRACKET . To loosen and tighten bolt -A-, counterhold it at drive plate -B- using a commercially available pin wrench -C- (pin diameter 5.0 mm). Bolt -A- is to be replaced (because of locking compound).

1. Carefully and uniformly pry off drive plate -A- using 2 screwdrivers -B-. (Scheme 119)

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 assignment.

Scheme 107

1. Remove securing ring -A-. (Scheme 120)
2. Remove pulley -B-.

Note. Replace securing ring -A-. 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 flat side facing compressor). Ensure proper seating of securing ring in groove on compressor flange. Clean compressor flange before fitting the pulley on, pulley must be able to be fitted easily. (fitting must be possible without much force).

Scheme 108

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.

Note. The following list refers to items in (Scheme 122).

1. Compressor drive unit Check, drive shaft must sit free of play in engine drive wheel splines with threads tightened. See «COMPRESSOR DRIVE SHAFT, REMOVING AND INSTALLING»(/audi/s6/c5-1999-2004/remont/automatic-hvac-system/#air-conditioning) . Tightening torque 60 Nm Loosening and tightening, see «COMPRESSOR DRIVE SHAFT, LOOSENING AND TIGHTENING»(/audi/s6/c5-1999-2004/remont/automatic-hvac-system/#air-conditioning__compressor-drive-shaft-loosening-and-tightening) Removing and installing, see «COMPRESSOR DRIVE SHAFT, REMOVING AND INSTALLING»(/audi/s6/c5-1999-2004/remont/automatic-hvac-system/#air-conditioning) Lubricate splines of engine drive wheel using G 000 100 clutch splining grease
2. Socket-head bolt Tightening torque 8 Nm
3. Drive plate With overload protection, disengages at a too high torque (e.g. when compressor does not move freely) and drive shaft moves freely without driving compressor. Checking and adjusting run out, see «RUN-OUT OF DRIVE PLATE WITH OVERLOAD PROTECTION, CHECKING AND ADJUSTING»(/audi/s6/c5-1999-2004/remont/automatic-hvac-system/#air-conditioning) Removing and installing, see «DRIVE PLATE WITH OVERLOAD PROTECTION, REMOVING AND INSTALLING»(/audi/s6/c5-1999-2004/remont/automatic-hvac-system/#air-conditioning__drive-plate-with-overload-protection-removing)
4. Drive plate Threaded to drive shaft of compressor Tightening torque 20 Nm Removing and installing, see «DRIVE PLATE TO COMPRESSOR, REMOVING AND INSTALLING»(/audi/s6/c5-1999-2004/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 (as lubricant). Removing and installing, see «DRIVE PLATE TO COMPRESSOR, REMOVING AND INSTALLING»(/audi/s6/c5-1999-2004/remont/automatic-hvac-system/#air-conditioning__drive-plate-to-compressor-removing-and)
6. Spacing disc Dimensions: 17.5 x 10 x 3 mm
7. Securing ring Replace Install on proper side (level side to compressor) Removing and installing, see «DRIVE PLATE WITH ROLLER BEARING, REMOVING AND INSTALLING»(/audi/s6/c5-1999-2004/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/s6/c5-1999-2004/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.

Scheme 109

Compressor drive shaft, loosening and tightening

1. Support engine using 10-222A engine support bridge (so that left engine mount can be removed). See «SUSPENSION - FRONT»(/audi/s6/c5-1999-2004/remont/suspension-front/#suspension-front) .

1. Remove oil dipstick from engine
2. Remove noise insulation: See «NOISE INSULATION PANEL, ASSEMBLY OVERVIEW»(/audi/s6/c5-1999-2004/remont/exterior-body-panels/#body-front__noise-insulation-panel-assembly-overview) .

1. Remove left engine mount completely (engine console, engine mount and engine support).

Drive shaft, loosening

1. Hold compressor drive shaft -A- in place using open-end wrench and turn compressor drive unit -B- in direction of arrow -C-. (Scheme 123)

Scheme 110

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). (Scheme 123)
2. After tightening compressor drive shaft, check installation position of boot -E

1. Remove compressor. See «COMPRESSOR FOR AUDI ALLROAD WITH 8 CYL. ENGINE, REMOVING AND INSTALLING»(/audi/s6/c5-1999-2004/remont/automatic-hvac-system/#air-conditioning).
2. Remove boot -A-. (Scheme 124)
3. Remove drive shaft -B- from splines of drive pinion -C-.

Scheme 111

Installing

Installation is the reverse of removal, noting the following

1. Check drive shaft -B-, splines must show no traces of wear and it must sit free of play in splines of drive wheel -C-. (Scheme 124)
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 FOR AUDI ALLROAD WITH 8 CYL. ENGINE, REMOVING AND INSTALLING»(/audi/s6/c5-1999-2004/remont/automatic-hvac-system/#air-conditioning) .

1. Remove bolts -A-. (Scheme 125)

Scheme 112

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

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/s6/c5-1999-2004/remont/automatic-hvac-system/#air-conditioning) .
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/s6/c5-1999-2004/remont/automatic-hvac-system/#air-conditioning) .

Scheme 113

1. Remove compressor. See «COMPRESSOR FOR AUDI ALLROAD WITH 8 CYL. ENGINE, REMOVING AND INSTALLING»(/audi/s6/c5-1999-2004/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.

Specified value: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)

1. If run-out deviation is greater than 0.2 mm, remove bolts on drive plate and adjust drive plate anew. See «DRIVE PLATE WITH OVERLOAD PROTECTION, REMOVING AND INSTALLING»(/audi/s6/c5-1999-2004/remont/automatic-hvac-system/#air-conditioning__drive-plate-with-overload-protection-removing) .

Drive plate to compressor, removing and installing

1. Remove drive plate with overload protection. See «DRIVE PLATE WITH OVERLOAD PROTECTION, REMOVING AND INSTALLING»(/audi/s6/c5-1999-2004/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 strap wrench (with webbed strap), counter hold compressor shaft -A- using a counterholder tool -B- (e.g. socket wrench from T10001/10 socket wrench set or 3079 counter holder) on compressor shaft -A-.

Scheme 114

Scheme 115

Scheme 116

1. When installing, coat rubber element lightly using tire mounting paste (as lubricant). (Scheme 128)
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- on to compressor shaft -A- by turning in direction of arrow -E-. (Scheme 129)
5. Tighten drive plate -C- by turning in direction of arrow -E- to 20 Nm using a commercially available strap wrench (with webbed strap), counter hold compressor shaft -A- using a counterholder tool -B- (for example, 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/s6/c5-1999-2004/remont/automatic-hvac-system/#air-conditioning__drive-plate-to-compressor-removing-and).
2. Remove securing ring -A-. (Scheme 130)
3. Remove drive plate -B-.

Scheme 117

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 flat side facing compressor).

A/C refrigerant circuit, servicing (compressor with A/C compressor regulator valve -N280-)

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) so much that the compressor will be damaged. 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 total amount of refrigerant oil to be filled into the refrigerant circuit (currently 220 cm 3 or 245 cm 3 ). Observe information on sticker attached on compressor. Capacities: See A/C REFRIGERANT R-134A AND REFRIGERANT OIL (PAG), CAPACITIES .

HP = High pressure side

LP = Low pressure side

Note. The following list refers to items in (Scheme 131).

1. A/C Compressor Regulator Valve -N280- Do not remove Checking activation and function, see Electrical Testing, «TEST STEP 5 TO 9»(/audi/s6/c5-1999-2004/remont/heated-glassdefoggers/#on-board-diagnostic-obd-hvac) NOTE: The A/C Compressor Regulator Valve -N280- is activated by the A/C control head -E87-, -N280- regulated the pressure on the low pressure side of the compressor.
2. Compressor O-ring seals for compressor: For low pressure-connection: 23.8 mm x 2.4 mm For high pressure-connection: 11.1 mm x 1.8 mm Refrigerant lines on compressor, removing and installing, see «REFRIGERANT LINES ON COMPRESSOR, DISCONNECTING AND CONNECTING (COMPRESSOR WITH A/C COMPRESSOR REGULATOR VALVE -N280-)»(/audi/s6/c5-1999-2004/remont/automatic-hvac-system/#air-conditioning__refrigerant-lines-on-compressor-disconnecting-and) To protect the compressor, the engine should only be started with the refrigerant circuit completely assembled. Remove ribbed belt. See appropriate ENGINE MECHANICAL article. Compressor removing and installing, see «REFRIGERANT LINES ON COMPRESSOR, DISCONNECTING AND CONNECTING (COMPRESSOR WITH A/C COMPRESSOR REGULATOR VALVE -N280-)»(/audi/s6/c5-1999-2004/remont/automatic-hvac-system/#air-conditioning__refrigerant-lines-on-compressor-disconnecting-and) Different compressor type depending on engine (installed on right or left side of engine, 6 cylinder engine In Audi Allroad with 4.2 L engine, compressor is not driven via a belt but via a drive shaft. See «COMPRESSOR (WITH A/C COMPRESSOR REGULATOR VALVE -N280-), REMOVING AND INSTALLING (IN A VEHICLES WITH 6 CYL. ENGINE)»(/audi/s6/c5-1999-2004/remont/automatic-hvac-system/#air-conditioning) . 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 clutch pulley, to speed up the oil drainage.
4. Compressor belt pulley/ drive unit Replacing belt pulley, see «COMPRESSOR BELT PULLEY/ DRIVE UNIT, REPLACING (COMPRESSOR WITHOUT A/C CLUTCH)»(/audi/s6/c5-1999-2004/remont/automatic-hvac-system/#air-conditioning) Checking, replacing compressor drive unit, see «COMPRESSOR DRIVE UNIT, CHECKING, REPLACING»(/audi/s6/c5-1999-2004/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/s6/c5-1999-2004/remont/automatic-hvac-system/#air-conditioning__high-pressure-sensor-g65-removing-and) Checking signal, see «TEST STEP 5: PRESSURE SIGNAL FROM HIGH PRESSURE SENSOR -G65»(/audi/s6/c5-1999-2004/remont/heated-glassdefoggers/#on-board-diagnostic-obd-hvac)
8. Condenser Refrigerant lines, removing and installing, see «REFRIGERANT LINES FOR CONDENSER, REMOVING AND INSTALLING»(/audi/s6/c5-1999-2004/remont/automatic-hvac-system/#air-conditioning__refrigerant-lines-for-condenser-removing-and) Condenser removing and installing, see «CONDENSER, REMOVING AND INSTALLING»(/audi/s6/c5-1999-2004/remont/automatic-hvac-system/#air-conditioning) . Different refrigerant R134a capacities depend on condenser. See «CAPACITIES»(/audi/s6/c5-1999-2004/remont/automatic-hvac-system/#air-conditioning__capacities) .
9. Closing cap With seal Always install
10. Service connection High pressure side For measuring, discharging and recharging.
11. Bolts in refrigerant line O-ring seals: 10.8 mm;1.8 mm Tightening torque: 15 Nm
12. Restrictor Installed in connection item 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/s6/c5-1999-2004/remont/automatic-hvac-system/#air-conditioning) . Before installing seal into restrictor, lubricate O-ring seal with refrigerant oil before
13. Evaporator Refrigerant lines, removing and installing, see «REFRIGERANT LINES ON EVAPORATOR, DISCONNECTING AND CONNECTING»(/audi/s6/c5-1999-2004/remont/automatic-hvac-system/#air-conditioning) Removing and installing air conditioner unit, see «COMPLETE AIR CONDITIONER UNIT, REMOVING AND INSTALLING»(/audi/s6/c5-1999-2004/remont/automatic-hvac-system/#air-conditioning__complete-air-conditioner-unit-removing-and) . Disassembling and assembling air conditioner, see «A/C UNIT, DISASSEMBLING AND ASSEMBLING»(/audi/s6/c5-1999-2004/remont/automatic-hvac-system/#air-conditioning__ac-unit-disassembling-and-assembling) Different versions, version "2" width of evaporator is 32 mm less than in version "1".
14. Service connection Low pressure side
15. Closing cap With seal Always install
16. Catch reservoir Removing and installing, see «CONDENSER, REMOVING AND INSTALLING»(/audi/s6/c5-1999-2004/remont/automatic-hvac-system/#air-conditioning__condenser-removing-and-installing)

Scheme 118

Condenser, removing and installing

Note. The connection of the refrigerant lines differs, depending on engine type. The construction of the accumulator differs, depending on model year and 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.

1. Discharge A/C refrigerant system. See «A/C REFRIGERANT SYSTEM (R-134A), DISCHARGING»(/audi/s6/c5-1999-2004/remont/automatic-hvac-system/#air-conditioning__ac-refrigerant-system-r-134a-discharging) .
2. Remove front bumper completely See «BUMPER»(/audi/s6/c5-1999-2004/remont/exterior-body-panels/#bumper) .

1. Bring bumper into service position if necessary. See «LOCK CARRIER, SERVICE POSITION»(/audi/s6/c5-1999-2004/remont/exterior-body-panels/#body-front__lock-carrier-service-position) .

1. Remove charge air cooler or the secondary air injection pump. See appropriate EXHAUST SYSTEM, EMISSION CONTROLS article.

Version "1" (with bolted connection and bracket), removing

1. Unscrew bolts -A-. (Scheme 132)
2. Remove refrigerant line -B- (tightening torque: 40 Nm).

Note. Replace both O-Ring-seals (17.2 mm x 1.8 mm). Seal all open connections. Install spring -C- so it is positioned against marking on refrigerant hose and engaged on bracket. (Scheme 132)

1. Remove hexagon nuts -D-. (Scheme 133)
2. Remove accumulator with bracket.
3. Remove refrigerant line -E- (tightening torque: 40 Nm).

Scheme 119

Note. Install refrigerant lines free of stress and make sure there is enough clearance to other components. When installing the accumulator in the bracket, always install insulation -F-.

Version "2" (with block and bolt connection), removing

1. Remove hexagon nuts -A- (tightening torque: 8 Nm).
2. Remove bolts -B- (tightening torque: 25 Nm).
3. Remove refrigerant line -C- (tightening torque: 40 Nm).
4. Remove refrigerant line -D-.

Scheme 120

Note. Replace both O-ring seals -E- and -F- (17.2 mm x 1.8 mm and 16.7 mm x 1.8 mm). Seal all open connections.

Scheme 121

1. Remove hexagon nuts -A-. (Scheme 135)
2. Loosen clamp -B
3. Remove bracket -C
4. Remove hexagon nuts -D- (tightening torque: 8 Nm).

Note. Only install accumulator with insulation -E-. (Scheme 135) Install spring -F- so it is positioned against marking on refrigerant hose and engaged on bracket

Scheme 122

Version "3" (with two block connections), removing

1. Remove bolts -A- (tightening torque 25 Nm) and remove refrigerant lines -B- and -C-. (Scheme 137)

Note. Replace both O-Ring-seals -D- and -E- (16.7 mm x 1.8 mm). (Scheme 137) Seal all open connections. The connection on the accumulator can be marked with "IN" (from evaporator) and "OUT" (to compressor).

Scheme 123

Scheme 124

1. Remove bolts -A- (tightening torque: 8 Nm). (Scheme 138)
2. Loosen notch on bracket for accumulator -B- from body
3. Remove accumulator with bracket.
4. Loosen screw -C- (tightening torque 8 Nm) and remove accumulator from bracket -D-.

Installing (all models)

Before installing accumulator

Note. When tightening refrigerant lines to accumulator, hold accumulator e.g. with oil filter strap (to avoid accumulator from turning). Install refrigerant lines free of stress and make sure there is enough clearance to other components. 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. 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 report: 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 an undefined amount of refrigerant oil escaped or dirt and moisture entered the system, clean refrigerant circuit with compressed air and nitrogen.

Installation is in reverse order of removal, observe notes and tightening torque for respective version (see removing notes)

1. Install all removed components again.
2. Evacuate and recharge refrigerant circuit. See «A/C REFRIGERANT SYSTEM (R-134A), EVACUATING AND RECHARGING»(/audi/s6/c5-1999-2004/remont/automatic-hvac-system/#air-conditioning__ac-refrigerant-system-r-134a-evacuating-and) .

Disconnecting

1. Discharge A/C refrigerant system. See «A/C REFRIGERANT SYSTEM (R-134A), DISCHARGING»(/audi/s6/c5-1999-2004/remont/automatic-hvac-system/#air-conditioning__ac-refrigerant-system-r-134a-discharging) .

1. Remove plenum cover.
2. Remove bolt -A- (tightening torque: 15 Nm). (Scheme 139)
3. Detach refrigerant lines from evaporator and seal off all open connections.

Note. To seal off all open connections for evaporator, cap -C- from replacement evaporator can be used (avoid dirt and moisture from entering the system).

Scheme 125

Connecting

Installation is the reverse order of removal, observe notes and tightening torque (see removing notes).

Note. Replace both O-Ring-seals -A- (16.7 mm x 1.8 mm) and -B- (10.8 mm x 1.8 mm). Install refrigerant lines free of stress. Make sure that grommet -D- is properly seated. Check position of refrigerant lines to evaporator, they should not come in contact with other components.

Scheme 126

1. Install all removed components again.
2. Evacuate and recharge refrigerant circuit. See «A/C REFRIGERANT SYSTEM (R-134A), EVACUATING AND RECHARGING»(/audi/s6/c5-1999-2004/remont/automatic-hvac-system/#air-conditioning__ac-refrigerant-system-r-134a-evacuating-and) .

1. Discharge A/C refrigerant system. See «A/C REFRIGERANT SYSTEM (R-134A), DISCHARGING»(/audi/s6/c5-1999-2004/remont/automatic-hvac-system/#air-conditioning__ac-refrigerant-system-r-134a-discharging) .

1. Remove plenum cover.
2. Unscrew connection -A- (tightening torque: 15 Nm).
3. Pull restrictor (orifice tube) -B- out of refrigerant line (for example, using long nose pliers).

Scheme 127

Installation is the reverse order of removal, observe notes and tightening torque (see removing notes).

Note. When replacing restrictor, observe color of restrictor and only install restrictor with same color (e.g. white or yellow), restrictors with different colors have different diameters in restrictor hole. See CAPACITIES and RESTRICTOR VERSION. Install restrictor -B- correctly (arrow on restrictor must face evaporator). (Scheme 141) Make sure that O-ring -C- (7.5 mm x 1.5 mm) is properly seated in the groove. Replace O-Ring-seal -D- (10.8 mm x 1.8 mm). Seal all open connections. The restrictor must fit in refrigerant line without play. Before installing O-ring for restrictor, lubricate lightly with refrigerant oil. Install refrigerant lines free of stress. Check position of refrigerant lines to evaporator, they should not come in contact with other components.

1. Install all removed components again.
2. Evacuate and recharge refrigerant circuit. See «A/C REFRIGERANT SYSTEM (R-134A), EVACUATING AND RECHARGING»(/audi/s6/c5-1999-2004/remont/automatic-hvac-system/#air-conditioning__ac-refrigerant-system-r-134a-evacuating-and) .

Refrigerant lines on compressor, disconnecting and connecting (compressor with A/C compressor regulator valve -N280-)

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) so much that the compressor will be 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. Currently refrigerant line brackets for these engines are not installed. Close all open lines and connections on compressor with suitable caps (avoid dirt and moisture from entering the system). Disconnect refrigerant lines in Audi Allroad with 8 cyl. engine. See COMPRESSOR FOR AUDI ALLROAD WITH 8 CYL. ENGINE, REMOVING AND INSTALLING .

1. Discharge A/C refrigerant system. See «A/C REFRIGERANT SYSTEM (R-134A), DISCHARGING»(/audi/s6/c5-1999-2004/remont/automatic-hvac-system/#air-conditioning__ac-refrigerant-system-r-134a-discharging) .
2. Remove noise insulation: See «NOISE INSULATION PANEL, ASSEMBLY OVERVIEW»(/audi/s6/c5-1999-2004/remont/exterior-body-panels/#body-front__noise-insulation-panel-assembly-overview) .
3. Remove bolt -A-, currently only installed on right hand side compressors).
4. Unscrew bolts -B-.

Scheme 128

Installation is reverse of removal, noting the following

1. Replace O-Ring-seals -D- (23.8 mm x 2.4 mm) and -E- (11.1 mm x1.8 mm).
2. Tighten bolts -B- to: 25 Nm. (Scheme 142)
3. Tighten bolt -A- to: 25 Nm.

Note. First tighten screw -B-, than tighten clamp -C- with bolt -A-. (Scheme 142) 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. (Scheme 143)

Scheme 129

Removing (compressor drive via belt)

1. Discharge A/C refrigerant system. See «A/C REFRIGERANT SYSTEM (R-134A), DISCHARGING»(/audi/s6/c5-1999-2004/remont/automatic-hvac-system/#air-conditioning__ac-refrigerant-system-r-134a-discharging) .
2. Disconnect refrigerant lines from compressor. See «REFRIGERANT LINES ON COMPRESSOR, DISCONNECTING AND CONNECTING (COMPRESSOR WITH A/C COMPRESSOR REGULATOR VALVE -N280-)»(/audi/s6/c5-1999-2004/remont/automatic-hvac-system/#air-conditioning__refrigerant-lines-on-compressor-disconnecting-and) .
3. Remove compressor from bracket. See «COMPRESSOR WITH A/C COMPRESSOR REGULATOR VALVE -N280-, REMOVING AND INSTALLING FROM BRACKET»(/audi/s6/c5-1999-2004/remont/automatic-hvac-system/#air-conditioning) .

Installation is reverse of removal, noting the following

Before installing compressor

1. Tightening torques and O-Ring-seals. See «REFRIGERANT LINES ON COMPRESSOR, DISCONNECTING AND CONNECTING (COMPRESSOR WITH A/C COMPRESSOR REGULATOR VALVE -N280-)»(/audi/s6/c5-1999-2004/remont/automatic-hvac-system/#air-conditioning__refrigerant-lines-on-compressor-disconnecting-and) .

1. Evacuate and recharge refrigerant circuit. See «A/C REFRIGERANT SYSTEM (R-134A), EVACUATING AND RECHARGING»(/audi/s6/c5-1999-2004/remont/automatic-hvac-system/#air-conditioning__ac-refrigerant-system-r-134a-evacuating-and) .
2. Run A/C system after installing compressor. See «A/C SYSTEM, RUNNING AFTER INSTALLATION OF COMPRESSOR»(/audi/s6/c5-1999-2004/remont/automatic-hvac-system/#air-conditioning__ac-system-running-after-installation-of) .

A/C system, running after installation of compressor

1. If a new compressor has been installed or new refrigerant oil has been put into the compressor (for example, 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.
2. Only start engine after refrigerant circuit has been assembled.
3. Only start engine with system recharged. NOTE: Different compressors, depending on engine Compressor is always driven (by belt pulley or via drive shaft to engine (it does not have an A/C clutch)
4. 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.
5. 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) so much that the compressor will be 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.
6. The necessary oil to lubricate the compressor is not transferred, since no refrigerant is available.
7. 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
8. The refrigerant circuit must be completely assembled.
9. At least one quarter of designated refrigerant oil for this circuit must be in the compressor.
10. Engine speed should not increase above 2500 RPM.
11. The engine should only runs as long as absolutely necessary
12. 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.

Scheme 130

Scheme 131

Scheme 132

1. Discharge A/C refrigerant system. See «A/C REFRIGERANT SYSTEM (R-134A), DISCHARGING»(/audi/s6/c5-1999-2004/remont/automatic-hvac-system/#air-conditioning__ac-refrigerant-system-r-134a-discharging).
2. Support engine using 10-222A engine support bridge (so that left engine mount can be removed).
3. Remove noise insulation: See «NOISE INSULATION PANEL, ASSEMBLY OVERVIEW»(/audi/s6/c5-1999-2004/remont/exterior-body-panels/#body-front__noise-insulation-panel-assembly-overview).
4. Disconnect refrigerant lines from condenser. See «REFRIGERANT LINES FOR CONDENSER, REMOVING AND INSTALLING»(/audi/s6/c5-1999-2004/remont/automatic-hvac-system/#air-conditioning__refrigerant-lines-for-condenser-removing-and).
5. Remove lock carrier completely: See «LOCK CARRIER WITH ATTACHMENTS, REMOVING AND INSTALLING»(/audi/s6/c5-1999-2004/remont/exterior-body-panels/#body-front__lock-carrier-with-attachments-removing-and).
6. Unscrew retaining clamp -arrow- for refrigerant line on bracket.
7. Remove oil dipstick from engine
8. Remove left engine mount completely (engine console, engine mount and engine support).
9. 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. (Scheme 145) Drive shaft -A- can be slid into drive wheel through the boot -E- after loosening threaded connection.
10. Remove bolts -A- (tightening torque 20 Nm). (Scheme 146)
11. Detach refrigerant lines from A/C compressor and seal off all open connections. See «REFRIGERANT LINES ON COMPRESSOR, DISCONNECTING AND CONNECTING (COMPRESSOR WITH A/C COMPRESSOR REGULATOR VALVE -N280-)»(/audi/s6/c5-1999-2004/remont/automatic-hvac-system/#air-conditioning__refrigerant-lines-on-compressor-disconnecting-and).
12. Disconnect 2-pin harness connector to A/C Compressor Regulator Valve -N280-. NOTE: Do not bend or stretch lines or hoses as condenser and/or refrigerant lines/hoses may be damaged.
13. Remove bolts -D- (tightening torque 25 Nm). (Scheme 146)
14. Remove compressor toward front.
15. Remove bushings -F- from compressor if necessary.

Before installing compressor

Scheme 133

Scheme 134

Scheme 135

Scheme 136

1. 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/s6/c5-1999-2004/remont/automatic-hvac-system/#air-conditioning).
2. Remove bushings -C- from compressor bracket if necessary. (Scheme 147)
3. Thoroughly clean contact surfaces -A- and -B- on bracket (and contact surfaces on compressor).
4. Install bushings -C- into compressor bracket. (Scheme 148) NOTE: Ensure that bushings -C- have proper seating 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.
5. Install compressor onto bracket with bolts -D- (and washers -E-) (tightening torque 25 Nm). (Scheme 149)
6. Connect refrigerant lines onto compressor (tightening torque of bolts -A- 20 Nm), dimensions of O-ring seals -B- and -C- as well as further notes. See «REFRIGERANT LINES ON COMPRESSOR, DISCONNECTING AND CONNECTING (COMPRESSOR WITH A/C COMPRESSOR REGULATOR VALVE -N280-)»(/audi/s6/c5-1999-2004/remont/automatic-hvac-system/#air-conditioning__refrigerant-lines-on-compressor-disconnecting-and).
7. After installing a new compressor or filling fresh refrigerant oil (e.g. after blowing through the A/C system to prevent damage on compressor), turn the compressor by hand via the compressor drive unit -B- in direction of arrow -C- 10 revolutions before tightening the drive shaft. (Scheme 150)
8. 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. After installing drive shaft -A-, check installation position of boot -E-.
9. Install all removed components again.
10. Evacuate and recharge refrigerant circuit. See «A/C REFRIGERANT SYSTEM (R-134A), EVACUATING AND RECHARGING»(/audi/s6/c5-1999-2004/remont/automatic-hvac-system/#air-conditioning__ac-refrigerant-system-r-134a-evacuating-and).
11. Run A/C system after installing compressor. See «REFRIGERANT LINES FOR CONDENSER, REMOVING AND INSTALLING»(/audi/s6/c5-1999-2004/remont/automatic-hvac-system/#air-conditioning__refrigerant-lines-for-condenser-removing-and).

Refrigerant lines for condenser, removing and installing

Note. The connection of the refrigerant lines differs, depending on engine type. The construction of the condenser differs, depending on model year and engine type.

1. Remove noise insulation: See «NOISE INSULATION PANEL, ASSEMBLY OVERVIEW»(/audi/s6/c5-1999-2004/remont/exterior-body-panels/#body-front__noise-insulation-panel-assembly-overview) .
2. Remove complete front bumper: See «BUMPER»(/audi/s6/c5-1999-2004/remont/exterior-body-panels/#bumper) .
3. Discharge A/C refrigerant system. See «A/C REFRIGERANT SYSTEM (R-134A), DISCHARGING»(/audi/s6/c5-1999-2004/remont/automatic-hvac-system/#air-conditioning__ac-refrigerant-system-r-134a-discharging) .

Removing refrigerant lines on version "1" (two connectors)

1. Loosen connectors on refrigerant lines -A- and -B- (tightening torque -A- 30 Nm and refrigerant lines -B- 15 Nm)
2. Remove refrigerant line -A- and -B-.

Note. Replace both O-Ring-seals -C- (14.0mm x 1.8mm) and -D- (10.8mm x 1.8mm). Close all open lines and connections on condenser with suitable caps (avoid dirt and moisture from entering the system). Notes for replacing condenser.

Scheme 137

Removing refrigerant lines on version "2" (two block connections on left side)

1. Remove bolts -A- (tightening torque 20 Nm).
2. Remove refrigerant line from condenser.

Note. Replace both O-Ring-seals -C- (14.0mm x 1.8mm) and -D- (10.8mm x 1.8mm). Close all open lines and connections on condenser with suitable caps (avoid dirt and moisture from entering the system). Notes for replacing condenser.

Scheme 138

Removing refrigerant lines on version "3" (one block connection on left side and one on right side)

1. Remove bolts -A- (tightening torque 20 Nm).
2. Remove refrigerant line from condenser.

Note. Replace both O-Ring-seals -C- (14.0mm x 1.8mm) and -D- (11.1mm x 1.8mm). Close all open lines and connections on condenser with suitable caps (avoid dirt and moisture from entering the system). Notes for replacing condenser. See A/C SYSTEM, REPLACING COMPONENTS .

Scheme 139

Installation is the reverse order of removal, observe notes and tightening torque for respective version (see removing notes)

1. Replace O-ring-seals. NOTE: When tightening bolts/nuts (on refrigerant lines) on condenser, counterhold condenser to prevent connection from twisting. Install refrigerant lines free of stress and make sure there is enough clearance to other components.
2. Check positions of refrigerant lines -A-, they must be fully engaged in bracket -B- and cannot come in contact with other components (different versions). (Scheme 154)
3. Install all removed components again.
4. Evacuate and recharge refrigerant circuit. See «A/C REFRIGERANT SYSTEM (R-134A), EVACUATING AND RECHARGING»(/audi/s6/c5-1999-2004/remont/automatic-hvac-system/#air-conditioning__ac-refrigerant-system-r-134a-evacuating-and).

1. Bring lock mount into service position. See «LOCK CARRIER, SERVICE POSITION»(/audi/s6/c5-1999-2004/remont/exterior-body-panels/#body-front__lock-carrier-service-position) .
2. Discharge A/C system. See «A/C REFRIGERANT SYSTEM (R-134A), DISCHARGING»(/audi/s6/c5-1999-2004/remont/automatic-hvac-system/#air-conditioning__ac-refrigerant-system-r-134a-discharging) .
3. Unscrew screws -A-. Tightening torque: 20 Nm (15 ft lb)
4. Disconnect refrigerant lines from condenser.

Scheme 140

Installation is the reverse of removal, noting the following

1. Replace O-ring seals -B- (14.0 mm/1.8 mm) and -C- (10.8 mm/1. 8 mm).

Note. The connection of the refrigerant lines differs, depending on engine type. The construction of the condenser differs, depending on model year and engine type. On vehicles with 2.0 L and 3.0 L gas engines, condensers with small flat pipes are installed. From week 5 in 1999 the running change to condensers with small flat pipes occurred on vehicles with 8 cylinder engines. Condensers -A- (manufacturer "Showa") with the following measurements of the flat pipes: -B- = 20 mm (Scheme 156) -C- = 3.0 mm...... require more refrigerant than condensers -D- (manufacturer "Denso") with the following measurements of the flat pipes: -E- = 18 mm or 16 mm (Scheme 156) -F- = 1.7 mm

Scheme 141

1. Observe the measurements of the flat pipes if the condenser is to be replaced with a different type of condenser. The data plate -A- including the capacity specification for refrigerant R134a has to be replaced or the old filling capacity has to be replaced and the new capacity must be filled in using a permanent pen.

Scheme 142

1. Discharge A/C refrigerant system. See «A/C REFRIGERANT SYSTEM (R-134A), DISCHARGING»(/audi/s6/c5-1999-2004/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/s6/c5-1999-2004/remont/automatic-hvac-system/#air-conditioning__refrigerant-lines-for-condenser-removing-and) .
3. Remove bumper. See «BUMPER»(/audi/s6/c5-1999-2004/remont/exterior-body-panels/#bumper) .
4. Remove air duct between bumper and condenser.

Removing, versions "1" and "2"

1. Remove air ducts -4-.
2. Remove bolts -1- and -2-.
3. Disconnect harness connector -3- from A/C Pressure Switch -F129-/High Pressure Sensor -G65-.
4. Remove condenser.

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

Scheme 143

Removing, version "3"

1. Remove air duct between bumper and condenser.
2. Disconnect connector from High Pressure Sensor -G65- -B-.
3. Remove bolts -A- (tightening torque: 5 Nm).

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

Scheme 144

Installation is the reverse order of removal, observe notes and tightening torque for the respective version (see removing notes)

1. Evacuate and recharge refrigerant circuit. See «A/C REFRIGERANT SYSTEM (R-134A), EVACUATING AND RECHARGING»(/audi/s6/c5-1999-2004/remont/automatic-hvac-system/#air-conditioning__ac-refrigerant-system-r-134a-evacuating-and) .

Scheme 145

Scheme 146

1. Discharge A/C refrigerant system. See «A/C REFRIGERANT SYSTEM (R-134A), DISCHARGING»(/audi/s6/c5-1999-2004/remont/automatic-hvac-system/#air-conditioning__ac-refrigerant-system-r-134a-discharging).
2. Remove front bumper as complete unit. See «BUMPER»(/audi/s6/c5-1999-2004/remont/exterior-body-panels/#bumper).
3. Remove bolts -A-. (Scheme 160)
4. Disconnect refrigerant line -B-. Tightening torque: 40 Nm (30 ft lb)
5. Remove nuts -D-. see scheme 161
6. Remove accumulator together with bracket.
7. Disconnect refrigerant line -E-. Tightening torque: 40 Nm (30 ft lb) NOTE: Replace both O-rings (17.2 mm x 1.8 mm).
8. Seal off all open connections.

Scheme 147

1. Install refrigerant lines free of stress and make sure there is sufficient clearance between lines and other components.
2. When installing the accumulator in the bracket, always install insulation -F-.
3. Install spring -C- so it is positioned against marking on refrigerant hose and engaged on bracket.

Scheme 148

Capacities

A/C refrigerant R134a and refrigerant oil (PAG), capacities: See A/C REFRIGERANT R-134A AND REFRIGERANT OIL (PAG), CAPACITIES .

Note. When charging the A/C system, always use the maximum amount of A/C refrigerant, since some of the refrigerant remains in the hose of the refrigerant recovery, recycling and recharging unit. In the engine compartment there is a sticker with data on the capacity and the type of refrigerant. The R134a refrigerant capacity depends on the version of the following components: Condenser Evaporator (integrated in air conditioner) Restrictor

Condenser version

1. On vehicles with 2.0 L and 3.0 L gas engines, condensers with small flat pipes are installed. From week 5 in 1999 the running change to condensers with small flat pipes occurred on vehicles with 8 cylinder engines. Condensers -A- (manufacturer "Showa") with the following measurements of the flat pipes
2. B- = 20 mm see scheme 164
3. C- = 3.0 mm...... require more refrigerant than condensers -D- (manufacturer "Denso") with the following measurements of the flat pipes
4. E- = 18 mm or 16 mm see scheme 164
5. F- = 1.7 mm

Scheme 149

1. Observe the measurement of the flat pipes if the condenser is to be replaced with a different type of condenser. The data plate -A- including the capacity specification for refrigerant R134a has to be replaced or the old filling capacity has to be replaced and the new capacity must be filled in using a permanent pen.

Scheme 150

Air conditioner unit

1. In the period from week 36 to week 44, 1998, there was a running change in production from version 1 air conditioner to version 2 air conditioner. Both versions can be differentiated through specific characteristics. See «CHARACTERISTICS OF AIR CONDITIONER VERSIONS 1 AND 2»(/audi/s6/c5-1999-2004/remont/automatic-hvac-system/#air-conditioning) .
2. Vehicles with air conditioner units version "2" require less refrigerant than unit version "1". See «CHARACTERISTICS OF AIR CONDITIONER VERSIONS 1 AND 2»(/audi/s6/c5-1999-2004/remont/automatic-hvac-system/#air-conditioning) .

1. Since November 1997, restrictors with a smaller hole have been installed in production, and are colored (at first yellow) so that they can be identified.
2. On vehicles in which the colored restrictors are installed, somewhat more refrigerant has to be added. See «RESTRICTOR VERSION»(/audi/s6/c5-1999-2004/remont/automatic-hvac-system/#air-conditioning__restrictor-version) .

Scheme 151

Refrigerant oil

See A/C REFRIGERANT R-134A AND REFRIGERANT OIL (PAG), CAPACITIES .

Note. Only approved refrigerant oils should be added to the refrigerant circuit Zexel, Sanden and Denso-compressors require different refrigerant oils. See A/C REFRIGERANT R-134A AND REFRIGERANT OIL (PAG), CAPACITIES . Different filling capacities for refrigerant oil depending on type and version of compressors (compressor with A/C Clutch -N25- or A/C Compressor Regulator Valve -N280-, or compressors with A/C Compressor Regulator Valve - N280-). See A/C REFRIGERANT R-134A AND REFRIGERANT OIL (PAG), CAPACITIES . Use only the specified oil from a sealed container and always reseal oil container immediately after use. Do not use oil if it has been contaminated with moisture or if oil container has been left open.

Compressor bracket, removing and installing (6 cyl. engine, compressor with A/C clutch -N25-)

1. Remove noise insulation and bring lock carrier to service position. See «NOISE INSULATION PANEL, ASSEMBLY OVERVIEW»(/audi/s6/c5-1999-2004/remont/exterior-body-panels/#body-front__noise-insulation-panel-assembly-overview) .
2. Ribbed belt and oil filter removing. See appropriate ENGINE MECHANICAL article.

Note. Mark running direction of ribbed belt before removing, reversed running direction may lead to belt damage. After removing, fasten compressor (e.g. using wire) to longmember. Do not let it hang on refrigerant line. Do not discharge A/C system. The compressor can be unbolted without opening refrigerant lines. Before removing the compressor, protect sealing surface between engine and oil cooler by covering. See appropriate ENGINE MECHANICAL article.

Scheme 152

Note. The following list refers to items in see scheme 167.

1. Compressor bracket
2. Hex bolt with washer Tightening torque 25 Nm.
3. Denso compressor with A/C clutch
4. Washer
5. Hex bolt Tightening torque 25 Nm.
6. Centering sleeves (dowel)

Complete air conditioner unit, removing and installing

1. Discharge refrigerant circuit. See «A/C REFRIGERANT SYSTEM (R-134A), DISCHARGING»(/audi/s6/c5-1999-2004/remont/automatic-hvac-system/#air-conditioning__ac-refrigerant-system-r-134a-discharging) .
2. Remove dust and pollen filter and its bracket. See «DUST AND POLLEN FILTER ELEMENT, REMOVING AND INSTALLING»(/audi/s6/c5-1999-2004/remont/automatic-hvac-system/#air-conditioning__dust-and-pollen-filter-element-removing) .
3. Disconnect battery cables and remove battery.

Note. Obtain radio code before disconnecting battery. On vehicles with power seats, move the seats back as far as possible before disconnecting the battery.

1. Release pressure in coolant system by opening cap on coolant expansion tank.
2. Clamp off and disconnect both coolant hoses leading to heater core in air conditioner unit (e.g. using VAG 3094)

Scheme 153

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 appropriate COOLING SYSTEM, MECHANICAL article.

Scheme 154

Scheme 155

Scheme 156

1. Place container beneath connection -A- and carefully blow out coolant from heater core (using compressed air) via connection -B-. see scheme 169
2. Remove grommet -C-.
3. Remove refrigerant line. See «REFRIGERANT LINES ON EVAPORATOR, DISCONNECTING AND CONNECTING»(/audi/s6/c5-1999-2004/remont/automatic-hvac-system/#air-conditioning).
4. Remove refrigerant lines and secure them (e.g. with cable tie) so they are not in the way during installation procedure.
5. Seal off refrigerant lines -B- and open connections -A- on evaporator. see scheme 170
6. Remove grommet -C-.
7. Remove storage compartment on driver's side, center console and instrument panel fascia. For storage compartment, see «DRIVER'S STORAGE COMPARTMENT, REMOVING»(/audi/s6/c5-1999-2004/remont/mirrors/#interior-equipment__drivers-storage-compartment-removing). For center console, see «CENTER CONSOLE (FRONT SECTION), REMOVING AND INSTALLING»(/audi/s6/c5-1999-2004/remont/mirrors/#interior-equipment__center-console-front-section-removing-and). Also see «INSTRUMENT PANEL»(/audi/s6/c5-1999-2004/remont/exteriorinterior-trim/#interior-trim).
8. Remove instrument panel cross member -A-. See «INSTRUMENT PANEL»(/audi/s6/c5-1999-2004/remont/exteriorinterior-trim/#interior-trim) and «CENTRAL TUBE, REMOVING AND INSTALLING»(/audi/s6/c5-1999-2004/remont/exteriorinterior-trim/#interior-trim). NOTE: The instrument panel cross member is fastened to the window cross member with an additional screw. See «HEATER CORE, REMOVING AND INSTALLING»(/audi/s6/c5-1999-2004/remont/automatic-hvac-system/#air-conditioning__heater-core-removing-and-installing).
9. Disconnect all electrical harness connectors for wiring between body and air conditioner unit -B-. NOTE: Before disconnecting, mark the connectors for the wiring to the various positioning motors so that they do not become interchanged when reconnecting.
10. Remove air conditioner unit -B-.

Note. Starting September 1998, there was a running change in production from the version "1" air conditioner to the version "2" air conditioner. See AIR CONDITIONING CHANGES . From model year 2002 air conditioner version "3" are installed. See AIR CONDITIONING CHANGES .

1. Before installing, check all gaskets and seals on the air conditioner unit for damage and replace if necessary.
2. After assembling, all cable ties which were removed in order to take out the air conditioner must be reinstalled in their original positions.
3. Replace both O-rings for the refrigerant lines.
4. Make sure refrigerant lines are not under stress when installed.
5. Make sure that the condensation drainage duct and condensation drain valve are properly seated.

A/C unit, disassembling and assembling

1. Air conditioner unit removing, see «COMPLETE AIR CONDITIONER UNIT, REMOVING AND INSTALLING»(/audi/s6/c5-1999-2004/remont/automatic-hvac-system/#air-conditioning__complete-air-conditioner-unit-removing-and) .

Note. Starting September 1998, there was a running change in production from the version "1" air conditioner to the version "2" air conditioner. See AIR CONDITIONING CHANGES . From model year 2002 air conditioner version "3" is installed. See AIR CONDITIONING CHANGES .

Note. The following list refers to items in see scheme 172.

1. Sender for outlet temperature, floor outlet -G192- Removing and installing, see «SENDER FOR OUTLET TEMPERATURE, FLOOR OUTLET -G192-, REMOVING AND INSTALLING»(/audi/s6/c5-1999-2004/remont/automatic-hvac-system/#air-conditioning__sender-for-outlet-temperature-floor-outlet) .
2. Bolt
3. Footwell vent
4. Air distributor housing With evaporator and heater core. Disassembling and assembling, see «A/C UNIT, DISASSEMBLING AND ASSEMBLING»(/audi/s6/c5-1999-2004/remont/automatic-hvac-system/#air-conditioning__ac-unit-disassembling-and-assembling) . Housing, air flaps, drip pan, evaporator and various other parts are different in versions 1 and 2. The position of the central flaps is different, from version "2", when the center flap is closed the two outer flaps remain slightly open (angle between both flaps approx. 40 degrees), on version "1" all flaps close simultaneously. On air conditioning version "1", the air guide to the intermediate piece (spacer) for defroster channel had two openings. Starting with version "2" the two openings have been combined into one opening. Starting with version "2", the evaporator can no longer be removed of the air distributor housing (the housing must be disassembled, due to the changed refrigerant line connection). Version "3" has an additional opening for installation of the Evaporator Vent Temperature Sensor -G263-. See «EVAPORATOR VENT TEMPERATURE SENSOR -G263-, REMOVING AND INSTALLING»(/audi/s6/c5-1999-2004/remont/automatic-hvac-system/#air-conditioning__evaporator-vent-temperature-sensor-g263-removing) (on vehicles without Evaporator Vent Temperature Sensor -G263- this opening is closed with a plug).
5. Combination bolt
6. Air flow duct with intake duct. Disassembling and assembling, see «A/C UNIT, DISASSEMBLING AND ASSEMBLING»(/audi/s6/c5-1999-2004/remont/automatic-hvac-system/#air-conditioning__ac-unit-disassembling-and-assembling) . The blower wheel for the fresh air blower installed in version "2" air conditioning unit is approx. 10 mm shorter than the one for version "1". From version "2", the air duct has been adapted to the changed fresh air blower. From version "2", the air duct at the fresh air blower fan is narrower than the air duct in version "1". From version "3" a second positioning motor has been installed at the intake duct. See «AIR FLOW FLAP MOTOR -V71-, REMOVING AND INSTALLING (VEHICLES UP TO MODEL YEAR 2002)»(/audi/s6/c5-1999-2004/remont/automatic-hvac-system/#air-conditioning__air-flow-flap-motor-v71-removing) and «RECIRCULATION FLAP MOTOR -V113-, REMOVING AND INSTALLING (VEHICLES FROM MODEL YEAR 2002)»(/audi/s6/c5-1999-2004/remont/automatic-hvac-system/#air-conditioning__recirculation-flap-motor-v113-removing-and) . From version "3", the air recirculating/fresh air flap is actuated by Recirculation Flap Motor -V113- and no longer by the Air Flow Flap Motor -V71-. See «AIR FLOW FLAP MOTOR -V71-, REMOVING AND INSTALLING (VEHICLES UP TO MODEL YEAR 2002)»(/audi/s6/c5-1999-2004/remont/automatic-hvac-system/#air-conditioning__air-flow-flap-motor-v71-removing) and «RECIRCULATION FLAP MOTOR -V113-, REMOVING AND INSTALLING (VEHICLES FROM MODEL YEAR 2002)»(/audi/s6/c5-1999-2004/remont/automatic-hvac-system/#air-conditioning__recirculation-flap-motor-v113-removing-and) .

Scheme 157

Air distribution housing, disassembling and assembling

1. Disassembling and assembling air conditioner unit, see «A/C UNIT, DISASSEMBLING AND ASSEMBLING»(/audi/s6/c5-1999-2004/remont/automatic-hvac-system/#air-conditioning__ac-unit-disassembling-and-assembling) .

Note. Starting September 1998, there was a running change in production from the version "1" air conditioner to the version "2" air conditioner. See AIR CONDITIONING CHANGES . From model year 2002 air conditioner version "3" is installed. See AIR CONDITIONING CHANGES . From model year 2002 for vehicles with compressor using A/C Compressor Regulator Valve -N280-, an additional Evaporator Vent Temperature Sensor is installed. See EVAPORATOR VENT TEMPERATURE SENSOR -G263-, REMOVING AND INSTALLING . (On vehicles without -G263- the opening is closed with a plug).

Note. The following list refers to items in see scheme 173.

1. Bolt
2. Clip
3. Foam sealing pad For condenser drainage duct
4. Bottom section of air distributor housing With condensation drainage duct Lower part of version "2" was adapted to modified evaporator
5. Drip pan For condensation from evaporator
6. Evaporator With seal From version "2", the width of the evaporator is 32 mm less than the width of the evaporator in version "1". Starting with version "2", the evaporator can no longer be removed from the air distributor housing (the housing must be disassembled, due to the changed refrigerant line connection).
7. Bolt
8. Refrigerant lines With insulation Refrigerant lines from version "2" were adapted to the modified evaporator After assembly, refrigerant lines and connector flange of evaporator must be wrapped completely with foam (for insulation)
9. Bracket
10. Bolt
11. O-ring seals Always replace Check for correct diameter. See «O-RING SEALS FOR REFRIGERANT CIRCUIT»(/audi/s6/c5-1999-2004/remont/automatic-hvac-system/#air-conditioning__o-ring-seals-for-refrigerant-circuit) . Different diameters, version "1": 2 piece 13.4 mm x 2.4 mm From version "2": 1 piece 13.4 mm x 2.4 mm 1 piece 10.8 mm x 2.4 mm
12. Central Air Flap Motor -V70-. With Potentiometer actuator for temperature flap left -G112-. Removing and installing, see «CENTRAL AIR FLAP MOTOR -V70-, REMOVING AND INSTALLING»(/audi/s6/c5-1999-2004/remont/automatic-hvac-system/#air-conditioning__central-air-flap-motor-v70-removing) .
13. Bolt
14. Actuator for temperature flap right -V159- With Potentiometer actuator for temperature flap left -G221-. Removing and installing, see «ACTUATOR FOR TEMPERATURE FLAP LEFT -V158-, REMOVING AND INSTALLING»(/audi/s6/c5-1999-2004/remont/automatic-hvac-system/#air-conditioning) .
15. Defroster flap motor -V107 With Potentiometer actuator for temperature flap left -G135-. Removing and installing, see «DEFROSTER FLAP MOTOR -V107-, REMOVING AND INSTALLING»(/audi/s6/c5-1999-2004/remont/automatic-hvac-system/#air-conditioning__defroster-flap-motor-v107-removing-and) . The lever arm on Defroster Flap Motor -V107- is different between air conditioning units "1" and "2".
16. Bolt
17. Bracket for Defroster Flap Motor -V107
18. Air distribution housing Do not disassemble further On vehicles that do not have additional heater element -Z35- the opening for the heater is closed. On air distributor housing units supplied as replacement parts the opening is open; if used on vehicles which do not have additional heater elements, the opening must be closed off using cap -29-. Housing, air flaps, drip pan, evaporator and various other parts are different in versions "1" and "2". On air conditioning version "1", the air guide to the intermediate piece (spacer) for defroster channel has two openings. Starting from version "2" the two openings have been combined into one opening. The position of the central flaps is different. From version "2", when the center flap is closed the two outer flaps remain slightly open (angle between both flaps approx. 40 degrees). On version "1" all flaps close simultaneously. Version "3" has an additional opening for the installation of Evaporator Vent Temperature Sensor -G263-. See «EVAPORATOR VENT TEMPERATURE SENSOR -G263-, REMOVING AND INSTALLING»(/audi/s6/c5-1999-2004/remont/automatic-hvac-system/#air-conditioning__evaporator-vent-temperature-sensor-g263-removing) . (On vehicles without Evaporator Vent Temperature Sensor -G263- this opening is closed with a plug).
19. Coolant pipe Return tube
20. Coolant pipe Supply tube
21. Bracket for refrigerant lines
22. Cover On version 2 with bracket for refrigerant lines
23. Bracket for refrigerant lines Only present on version "1"
24. Actuator for temperature flap left -V158- With Potentiometer- actuator for temperature flap left -G220-. Removing and installing, see «ACTUATOR FOR TEMPERATURE FLAP LEFT -V158-, REMOVING AND INSTALLING»(/audi/s6/c5-1999-2004/remont/automatic-hvac-system/#air-conditioning) .
25. Clamp Always replace Check for proper seating
26. O-ring seals Always replace
27. Heater core Removing and installing, see «HEATER CORE, REMOVING AND INSTALLING»(/audi/s6/c5-1999-2004/remont/automatic-hvac-system/#air-conditioning__heater-core-removing-and-installing) .
28. Heater element for auxiliary heater -Z35- (not for USA)
29. Cover Only on vehicles with no heater element for additional heater The cap is the same as cap on heater element for additional heater, except openings for connectors are sealed (air tight)
30. Rubber mounting

Scheme 158

Air duct with intake housing, disassembling and assembling

1. Air conditioner unit removing, see «COMPLETE AIR CONDITIONER UNIT, REMOVING AND INSTALLING»(/audi/s6/c5-1999-2004/remont/automatic-hvac-system/#air-conditioning__complete-air-conditioner-unit-removing-and) .
2. Disassembling and assembling air conditioner unit, see «A/C UNIT, DISASSEMBLING AND ASSEMBLING»(/audi/s6/c5-1999-2004/remont/automatic-hvac-system/#air-conditioning__ac-unit-disassembling-and-assembling) .

Note. Starting September 1998, there was a running change in production from the version "1" air conditioner to the version "2" air conditioner. See AIR CONDITIONING CHANGES . From model year 2002 air conditioner version "3" is installed. See AIR CONDITIONING CHANGES . From version "3" a second positioning motor has been installed at the intake duct. See AIR FLOW FLAP MOTOR -V71-, REMOVING AND INSTALLING (VEHICLES UP TO MODEL YEAR 2002) and RECIRCULATION FLAP MOTOR -V113-, REMOVING AND INSTALLING (VEHICLES FROM MODEL YEAR 2002) . From version "3", the air recirculating/fresh air flap is actuated by Recirculation Flap Motor -V113- and no longer by the Air Flow Flap Motor -V71-. See AIR FLOW FLAP MOTOR -V71-, REMOVING AND INSTALLING (VEHICLES UP TO MODEL YEAR 2002) and RECIRCULATION FLAP MOTOR -V113-, REMOVING AND INSTALLING (VEHICLES FROM MODEL YEAR 2002) .

Air duct and intake housing (vehicles up to model year 2001)

Note. The following list refers to items in see scheme 174.

1. Bolt
2. Control module for fresh air blower -J126- Removing and installing, see «CONTROL MODULE FOR FRESH AIR BLOWER -J126-, REMOVING AND INSTALLING»(/audi/s6/c5-1999-2004/remont/automatic-hvac-system/#air-conditioning__control-module-for-fresh-air-blower) .
3. Bolt
4. Fresh Air Blower -V2- Removing and installing, see «FRESH AIR BLOWER -V2-, REMOVING AND INSTALLING»(/audi/s6/c5-1999-2004/remont/automatic-hvac-system/#air-conditioning__fresh-air-blower-v2-removing-and) . The blower wheel for the fresh air blower installed in version "2" air conditioning unit is approx. 10 mm shorter than the one in version "1".
5. Air duct Do not disassemble further From version "2", the air duct has been adapted to the changed fresh air blower. From version "2", the air duct at the fresh air blower fan is narrower than the air duct in version "1".
6. Intake housing (version "1" and "2") Do not disassemble further With fresh air/recirculated air flap and two air flow flaps
7. Foam sealing pad Forms seal between intake housing and vehicle body
8. Bracket for Air Flow Flap Motor -V71
9. Bolt
10. Air Flow Flap Motor -V71- Actuates air flow flap and fresh air/recirculated air flap With Defroster Flap Motor Position Sensor -G135- (Recirculation Flap Motor Position Sensor -G143-) Removing and installing, see «AIR FLOW FLAP MOTOR -V71-, REMOVING AND INSTALLING (VEHICLES UP TO MODEL YEAR 2002)»(/audi/s6/c5-1999-2004/remont/automatic-hvac-system/#air-conditioning__air-flow-flap-motor-v71-removing) .
11. Fresh Air Intake Duct Temperature Sensor -G89

1. Removing and installing, see «FRESH AIR INTAKE DUCT TEMPERATURE SENSOR -G89-, REMOVING AND INSTALLING»(/audi/s6/c5-1999-2004/remont/automatic-hvac-system/#air-conditioning__fresh-air-intake-duct-temperature-sensor) .

Scheme 159

Air duct and intake housing (vehicles from model year 2002)

Note. The following list refers to items in see scheme 175.

1. Bolt
2. Control module for fresh air blower -J126- Removing and installing, see «CONTROL MODULE FOR FRESH AIR BLOWER -J126-, REMOVING AND INSTALLING»(/audi/s6/c5-1999-2004/remont/automatic-hvac-system/#air-conditioning__control-module-for-fresh-air-blower) .
3. Bolt
4. Fresh Air Blower -V2- Removing and installing, see «FRESH AIR BLOWER -V2-, REMOVING AND INSTALLING»(/audi/s6/c5-1999-2004/remont/automatic-hvac-system/#air-conditioning__fresh-air-blower-v2-removing-and) . The blower wheel for the fresh air blower installed in version "2" air conditioning unit is approx. 10 mm shorter than the one in version "1".
5. Air duct Do not disassemble further Air duct for version "2" From version "2", the air duct at the fresh air blower fan is narrower than the air duct in version "1".
6. Intake housing (version "3") Do not disassemble further With fresh air/recirculated air flap and two air flow flaps On intake housing version "3", the fresh air/recirculated air flap has a positioning motor as well as the back pressure flap
7. Foam sealing pad Forms seal between intake housing and vehicle body
8. Bracket for Recirculation Flap Motor -V113
9. Recirculation Flap Motor -V113- Actuated by fresh air/recirculating flap With Recirculation- Flap Motor Position Sensor -G143- Removing and installing, see «RECIRCULATION FLAP MOTOR -V113-, REMOVING AND INSTALLING (VEHICLES FROM MODEL YEAR 2002)»(/audi/s6/c5-1999-2004/remont/automatic-hvac-system/#air-conditioning__recirculation-flap-motor-v113-removing-and)
10. Bolt
11. Bolt
12. Air Flow Flap Motor -V71-. Actuates back pressure flaps With Back Pressure Flap Motor Position Sensor -G113- Removing and installing, see «RECIRCULATION FLAP MOTOR -V113-, REMOVING AND INSTALLING (VEHICLES FROM MODEL YEAR 2002)»(/audi/s6/c5-1999-2004/remont/automatic-hvac-system/#air-conditioning__recirculation-flap-motor-v113-removing-and)
13. Fresh Air Intake Duct Temperature Sensor -G89

1. Removing and installing, see «FRESH AIR INTAKE DUCT TEMPERATURE SENSOR -G89-, REMOVING AND INSTALLING»(/audi/s6/c5-1999-2004/remont/automatic-hvac-system/#air-conditioning__fresh-air-intake-duct-temperature-sensor) .

Scheme 160

Using VAG 1551 Scan Tool (ST), check DTC memory for any electrical, vacuum or air distribution malfunctions. Correct/repair as necessary berfore proceeding. See ON BOARD DIAGNOSTIC (OBD), INITIATING .

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/s6/c5-1999-2004/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/s6/c5-1999-2004/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 BRACKET, REMOVING AND INSTALLING (6 CYL. ENGINE, COMPRESSOR WITH A/C CLUTCH -N25-)»(/audi/s6/c5-1999-2004/remont/automatic-hvac-system/#air-conditioning__compressor-bracket-removing-and-installing-6) .
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/s6/c5-1999-2004/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/s6/c5-1999-2004/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).

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 A/C REFRIGERANT R-134A AND REFRIGERANT OIL (PAG), CAPACITIES . 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 A/C REFRIGERANT R-134A AND REFRIGERANT OIL (PAG), CAPACITIES . 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/s6/c5-1999-2004/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/s6/c5-1999-2004/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/s6/c5-1999-2004/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/s6/c5-1999-2004/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/s6/c5-1999-2004/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).
5. 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 cm3 (2.4 oz) of refrigerant oil was poured out. From the replacement compressor 220 cm3 of refrigerant oil poured out (a small amount remains in compressor). 70 cm3 (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 cm3 (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/s6/c5-1999-2004/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/s6/c5-1999-2004/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.
3. Blow through A/C system with compressed air and nitrogen. See «A/C REFRIGERANT SYSTEM (R-134A), FLUSHING WITH COMPRESSED AIR AND NITROGEN»(/audi/s6/c5-1999-2004/remont/automatic-hvac-system/#air-conditioning__ac-refrigerant-system-r-134a-flushing-with) .
4. Replace accumulator and restrictor.
5. Assemble A/C system, evacuate and charge. See «A/C REFRIGERANT SYSTEM (R-134A), EVACUATING AND RECHARGING»(/audi/s6/c5-1999-2004/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/s6/c5-1999-2004/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/s6/c5-1999-2004/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).
8. 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 «A/C REFRIGERANT R-134A AND REFRIGERANT OIL (PAG), CAPACITIES»(/audi/s6/c5-1999-2004/remont/automatic-hvac-system/#air-conditioning) . To ensure adequate compressor lubrication, add at least 80 cm3 (2.7 oz) of refrigerant oil into compressor. The remainder can be added to new accumulator. See «A/C REFRIGERANT R-134A AND REFRIGERANT OIL (PAG), CAPACITIES»(/audi/s6/c5-1999-2004/remont/automatic-hvac-system/#air-conditioning) . If there is dirt in the compressor of an open A/C system (e.g. during an accident), replace compressor.
9. Blow through A/C circuit with compressed air and nitrogen.
10. Replace accumulator and restrictor.
11. Assemble A/C system, evacuate and charge. See «A/C REFRIGERANT SYSTEM (R-134A), EVACUATING AND RECHARGING»(/audi/s6/c5-1999-2004/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/s6/c5-1999-2004/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/s6/c5-1999-2004/remont/automatic-hvac-system/#air-conditioning__ac-refrigerant-system-r-134a-evacuating-and) .

See also:
• TEST STEP 5: PRESSURE SIGNAL FROM HIGH PRESSURE SENSOR -G65
• TEST STEP 6: ACTIVATION FOR A/C COMPRESSOR REGULATOR VALVE -N280
• BUMPER
• OUTPUT DIAGNOSTIC TEST MODE (DTM)
• A/C CONTROL HEAD -E87-, CODING
• LOCK CARRIER, SERVICE POSITION
• SUNROOF
• SENSOR FOR AIR QUALITY -G238-, FUNCTION
• DISPLAY GROUP 017: MEASURING VALUES FOR SUNLIGHT PHOTO SENSOR -G107-, SIGNAL FROM WINDSHIELD WIPER SWITCH FOR WASHER PUMP AND WINDSHIELD WIPER
• INSTRUMENT PANEL
• READ MEASURING VALUE BLOCK (FUNCTION 08)
• RADIO SYSTEMS
• GLOVE BOX, REMOVING AND INSTALLING
• DRIVER'S STORAGE COMPARTMENT, REMOVING
• STORAGE COMPARTMENTS, COVERS AND TRIM PARTS
• EMERGENCY BATTERY, SWITCHING OFF/ON
• WINDSHIELD WIPER AND WASHER SYSTEM - 2001 AND UP
• BASIC SETTING (FUNCTION 04)
• READ MEASURING VALUE BLOCKS (VEHICLES UP TO MODEL YEAR 2001)
• ELECTRICAL TESTING (VEHICLES FROM MODEL YEAR 2002)
• NOISE INSULATION PANEL, ASSEMBLY OVERVIEW
• SUSPENSION - FRONT
• LOCK CARRIER WITH ATTACHMENTS, REMOVING AND INSTALLING
• CENTER CONSOLE (FRONT SECTION), REMOVING AND INSTALLING
• A/C REFRIGERANT SYSTEM (R-134A), EVACUATING AND RECHARGING
• A/C REFRIGERANT SYSTEM (R-134A), DISCHARGING
• REFRIGERANT CIRCUIT, SERVICING
• A/C REFRIGERANT SYSTEM, PRESSURE AND TEMPERATURE RELATIONSHIPS
• CRITICAL TEMPERATURE/CRITICAL PRESSURE
• A/C SYSTEM, SAFETY PRECAUTIONS
• A/C PRESSURE SWITCH -F129
• O-RINGS
• TABLE OF PRESSURE AND TEMPERATURE RELATIONSHIPS
• A/C REFRIGERANT SYSTEM, CHECKING PRESSURES
• A/C SYSTEM WITH RESTRICTOR AND ACCUMULATOR, REFRIGERANT FLOW
• COMPRESSOR, WITH A/C CLUTCH -N25
• COMPRESSOR, WITH A/C COMPRESSOR REGULATOR VALVE -N280
• A/C REFRIGERANT SYSTEM, SERVICING
• A/C SYSTEM COOLING PERFORMANCE, TESTING
• COMPRESSOR BRACKET, REMOVING AND INSTALLING (6 CYL. ENGINE, COMPRESSOR WITH A/C CLUTCH -N25-)
• DENSO COMPRESSOR, REMOVING AND INSTALLING FROM BRACKET (8 CYL. ENGINE WITH A/C CLUTCH - N25-)
• A/C CLUTCH -N25-, SERVICING (DENSO COMPRESSOR)
• HIGH PRESSURE SENSOR -G65-, REMOVING AND INSTALLING
• COMPLETE AIR CONDITIONER UNIT, REMOVING AND INSTALLING
• A/C UNIT, DISASSEMBLING AND ASSEMBLING
• LOOSEN AND TIGHTEN HEX BOLT
• REMOVING CLUTCH PLATE
• INSTALLING MAGNETIC COIL
• O-RING SEALS FOR REFRIGERANT CIRCUIT
• AIR EXTRACTION VENT, CHECKING
• EVAPORATOR HOUSING DRAIN VALVE, CHECKING, REMOVING AND INSTALLING
• DUST AND POLLEN FILTER ELEMENT, REMOVING AND INSTALLING
• DUST AND POLLEN FILTER WITH ACTIVE CARBON FILTER ELEMENT
• CENTRAL AIR FLAP MOTOR -V70-, REMOVING AND INSTALLING
• SENSOR FOR AIR QUALITY -G238-, REMOVING AND INSTALLING
• SENDER FOR OUTLET TEMPERATURE, FLOOR OUTLET -G192-, REMOVING AND INSTALLING
• HEATER CORE, REMOVING AND INSTALLING
• LEFT VENT TEMPERATURE SENSOR -G150-, REMOVING AND INSTALLING
• LEFT INSTRUMENT PANEL VENT, REMOVING AND INSTALLING
• LEFT AND RIGHT SIDE WINDOW DEFROSTER VENTS, REMOVING AND INSTALLING
• SUNLIGHT PHOTO SENSOR -G107-, REMOVING AND INSTALLING
• A/C CONTROL HEAD -E87-, REMOVING AND INSTALLING
• ACTUATOR FOR TEMPERATURE FLAP RIGHT -V159-, REMOVING AND INSTALLING
• DEFROSTER FLAP MOTOR -V107-, REMOVING AND INSTALLING
• FRESH AIR BLOWER -V2-, REMOVING AND INSTALLING
• RIGHT VENT TEMPERATURE SENSOR -G151-, REMOVING AND INSTALLING
• FRESH AIR INTAKE DUCT TEMPERATURE SENSOR -G89-, REMOVING AND INSTALLING
• AIR FLOW FLAP MOTOR -V71-, REMOVING AND INSTALLING (VEHICLES UP TO MODEL YEAR 2002)
• CONTROL MODULE FOR FRESH AIR BLOWER -J126-, REMOVING AND INSTALLING
• CENTER INSTRUMENT PANEL VENT, REMOVING AND INSTALLING
• EVAPORATOR VENT TEMPERATURE SENSOR -G263-, REMOVING AND INSTALLING
• RECIRCULATION FLAP MOTOR -V113-, REMOVING AND INSTALLING (VEHICLES FROM MODEL YEAR 2002)
• COMPRESSOR DRIVE UNIT, CHECKING, REPLACING
• NOTES FOR TEST STEP 27
• IDENTIFYING MALFUNCTIONS AT TEMPERATURE INCREASE BEHIND CONDENSER
• A/C SYSTEM, QUICK COUPLING CONNECTIONS
• A/C SYSTEM, REPLACING COMPONENTS
• DETERMINING DIMENSIONS OF FLAT TUBES FROM CONDENSER
• REFRIGERANT LINES FROM DENSO COMPRESSOR (WITH A/C CLUTCH -N25-), REMOVING AND INSTALLING
• REFRIGERANT LINES FOR CONDENSER, REMOVING AND INSTALLING
• CAPACITIES
• CONDENSER, REMOVING AND INSTALLING
• REFRIGERANT LINES ON COMPRESSOR, DISCONNECTING AND CONNECTING (COMPRESSOR WITH A/C COMPRESSOR REGULATOR VALVE -N280-)
• PULLEY, REMOVING FROM COMPRESSOR AND INSTALLING
• COMPRESSOR DRIVE SHAFT, LOOSENING AND TIGHTENING
• DRIVE PLATE WITH OVERLOAD PROTECTION, REMOVING AND INSTALLING
• DRIVE PLATE TO COMPRESSOR, REMOVING AND INSTALLING
• DRIVE PLATE WITH ROLLER BEARING, REMOVING AND INSTALLING
• RESTRICTOR VERSION
• A/C SYSTEM, RUNNING AFTER INSTALLATION OF COMPRESSOR
• A/C REFRIGERANT SYSTEM (R-134A), FLUSHING WITH COMPRESSED AIR AND NITROGEN