Heating Air Conditioning: Overview Audi A8 D3 facelift 2

Display in display groups "006" to "007" for vehicles manufactured as of November 2002 (gradual introduction)

Note. The display in display groups "006" and "007" differs depending on whether Rear A/C Control Head (Climatronic) E265 was installed prior to or as of November 2002. Furthermore, display group "008" was no longer used in version as of November 2002. At the start of production, Rear A/C Control Head (Climatronic) E265 were installed for which values are displayed in display group "008".

Overview of designated adaptation channels

Note. This article lists the various adaption channels for information purposes only. Perform the function "Adaptation" in Guided Fault Finding, here an explanation can also be found for the regulating function changes performed in the adaptation channels and applicable notes. Vehicle Diagnosis, Testing and Information System VAS 5051 in "Guided Fault Finding" function. Adaptation channels "22" and "23" are only reserved in , Climatronic Control Module J255 installed until approx. December 2002; adaptation of these channels can only performed with , Climatronic Control Module J255 installed as of December 2002 (gradual introduction at factory) Vehicle Diagnosis, Testing and Information System VAS 5051 in "Guided Fault Finding" function.

Note. The various adaptation channels are listed only for information in this article. Perform the function "Adaptation" in Guided Fault Finding, here an explanation can also be found for the regulating function changes performed in the adaptation channels and applicable notes. Vehicle Diagnosis, Testing and Information System VAS 5051 in "Guided Fault Finding" function. Rear A/C Control Head (Climatronic) E265 installed at start of production, cannot or do not have to be adapted. Following introduction of "Seat ventilation" as optional equipment (gradual introduction at factory as of December 2002), these rear A/C control heads can and must also be adapted. Vehicle Diagnosis, Testing and Information System VAS 5051 in "Guided Fault Finding" function.

Air Quality Sensor G238 , mode of operation

1. Depending on setting in MMI (Multi Media Interface), the sunroof closes as soon as Climatronic Control Module J255 switches over to air recirculation mode (automatic air recirculation via air quality sensor or manual air recirculation by operating the air recirculation button). This function is equipment-dependent, its introduction has not yet been finalized. Owners Manual
2. Air Quality Sensor G238 detects pollutants in the ambient air (mostly gasoline and or diesel exhaust) and orders Climatronic Control Module J255 to switch the air conditioning system to recirculating air mode.
3. Climatronic Control Module J255 detects the type and intensity of air pollution at signal from sensor. Depending on the outside temperature and the intensity of air pollution, Climatronic Control Module J255 then decides

1. At an outside temperature greater than approx: + 2°C (36 F) the recirculating air mode is switched on when there is only a slight increase in pollutants in the ambient air
2. At an outside temperature between approx. + 2°C and approx. - 8°C, the change over to recirculating air mode only occurs at a sharp increase of pollutant concentration, during which the compressor is switched on simultaneously
3. At an outside temperature less than approx. - 8°C, the change over still occurs only at a sharp increase of pollutant concentration and then only for approx. 15 s (compressor is not switched on).
4. If the concentration drops, the climate control system switches over to the fresh air mode.

1. The function "Automatic air recirculation" can be switched off at any time. If the function is active and a request for "Automatic air recirculation" is present the compressor is also switched on when outside temperatures are smaller than + 2°C. Compressor operation is not possible with temperatures lower than approx. -8°C.
2. At setting "automatic air recirculation" on Climatronic Control Module J255 or in MMI (Multi Media Interface), compressor can be switched on also by switching on recirculating air manually (via "recirculating air button") up to a temperature of approx. - 8°C.
3. To ensure that the A/C does not operate constantly in the recirculating air mode in areas with a consistently higher pollution, the sensor is self-adapting (it adjusts its sensitivity to the environmental conditions).
4. If outside air pollution load remains high for longer period of time, the sensor starts to adapt itself to the changing environmental condition through an adaptation program (learning program), the air recirculation request in evenly polluted ambient air is therefore generally shorter than 12 minutes. If a succession of peaks in the polluted air is detected, the air conditioning system can operate over a longer period of time in recirculated air mode.

1. A certain amount of time is required for repositioning of the air conditioning system flaps. In the event that a sudden increase in pollutants is encountered (e.g. when driving through a diesel exhaust cloud) gaseous pollutants can be taken in with the fresh air into the passenger compartment until the flaps can be closed. For this reason, a dust and pollen filter is installed with a charcoal layer. A filter that is saturated with pollutants is no longer effective and needs to be replaced --> «Dust and pollen filter, removing and installing»(ref-289225-S02097241612008062700000) .
2. In order to avoid frequent shifting of the recirculating air/fresh air flaps, a slight increase of pollutants in the ambient air will not allow for immediate shifting (the sensor does not send a request to Climatronic Control Module J255). The filtering of the charcoal insert in the dust and pollen filter will be sufficient --> «Dust and pollen filter with activated charcoal filter element»(ref-289225-S06244391772008062700000) .
3. In order to avoid frequent shifting of the recirculating air/fresh air flap, the requirement from the sensor for "Automatic air recirculation" mode remains for at least 25 seconds (minimum duration period), even if the pollutant concentration is so far reduced that recirculating air mode is no longer necessary.
4. If the compressor is shut-off (e.g. in "Econ" mode), the maximum duration of the "Automatic recirculating air mode" is limited to approx. 15 seconds by Climatronic Control Module J255 to avoid windows from fogging up.

1. In order to defog windows as quickly as possible, Climatronic Control Module J255 does not permit recirculating air operation during "Defrost" operating mode.
2. After the ignition is switched on, Air Quality Sensor G238 requires approx. 30 seconds to be operational (warm-up time). During this time there is no request from the sensor to A/C control head Climatronic Control Module J255 for "Automatic recirculating air" mode.
3. The Sensor for air quality G238 contains a highly sensitive electronic component which can be damaged if it comes in direct contact with solvents, fuels or chemicals. For this reason, do not install sensors that may have come into contact with these substances.

Checking operation of solar roof

1. Place vehicle in direct sunlight.

Note. If weather conditions are unfavorable, the solar sunroof can be illuminated using two commercially available 1000 W halogen lamps. A distance of at least 500 mm from the solar roof must be maintained. Make sure that all sunroof Solar Cells C20 are illuminated completely and evenly so that the Solar Cells C20 can supply sufficient electrical energy to drive the Fresh Air Blower V2 , Depending on version, the actual power output of Solar Cells C20 (voltage and current) is displayed in measured value block of Climatronic Control Module J255 (display group 44) directly after switching off ignition Vehicle Diagnosis, Testing and Information System VAS 5051 in "Guided Fault Finding" function.

1. Open the "center" instrument panel vents and close the remaining vents.
2. Check setting on Climatronic Control Module J255 or an MMI (Multi Media Interface), "solar mode" function must be set.
3. Close sunroof.
4. Switch off ignition (is blank).

A current of air can be felt from the dash panel vents (check by moistening palm of hand if necessary).

If no air flow can be detected

1. Check DTC memory of Climatronic Control Module J255 and check coding of. Vehicle Diagnosis, Testing and Information System VAS 5051 in "Guided Fault Finding" function.
2. Check setting (and adaptation if necessary) on Climatronic Control Module J255 and on MMI ("solar mode" function must be activated).
3. Switch off ignition.
4. Remove air intake housing with air flow flap --> «Intake housing with air flow flap, removing and installing»(ref-289225-S35130398122008062700000) .

Scheme 1

1. Disconnect connector - A - from Fresh Air Blower Control Module J126.
2. Measure voltage between terminal - 2 - (of solar roof) and terminal - 4 - (ground) at connector - A -.

1. Specification:8 - 12 V = (depending on intensity of the solar radiation)

1. Connect a test lamp (12 V with maximum 5 W) between terminals - 2 - and - 4 - on connector - A -.
2. Test lamp glows or lights (depending on sunlight intensity).

Note. Solar roof function is OK if test lamp glows or lights up. If fresh-air blower does not run, check Fresh Air Blower V2 for freedom of movement and actuation of Fresh Air Blower Control Module J126 by. If no fault is found, replace Climatronic Control Module J255. If test lamp does not glow or light up, check wire connection to both terminals at sunroof cut-out --> Electrical Wiring Diagrams, Troubleshooting and Component Locations. If no fault is found, check solar panel. --> 60 - SUNROOF Only a small energy of 1.5 W is supplied on shining halogen lamps onto solar roof (fresh-air blower rotates but air flow is hardly recognizable). The current, which is sent from sunroof with Solar Cells C20 to the Fresh Air Blower V2 , can be read out in measuring value block (display group "044") depending on version of the Climatronic Control Module J255. Place vehicle in direct sunlight, e.g. with sunroof closed (or beneath two lamps as described above), and select respective measuring value block of , Climatronic Control Module J255 , Vehicle Diagnosis, Testing and Information System VAS 5051 in "Guided Fault Finding" function. After switching off the ignition, the current is then displayed which was sent from sunroof with Solar Cells C20 when switching off the ignition (and the brief period afterward).

Scheme 2

1. Heated Windshield Control Module J505 - A - is installed in left luggage compartment beneath battery A (vehicle battery).
2. Heated Windshield Control Module J505 - A - is actuated by , Climatronic Control Module J255 (read measured value block, display group "045" to "047"). Vehicle Diagnosis, Testing and Information System VAS 5051 in "Guided Fault Finding" function.

1. After starting cold engine if outside temperature is less than + 5°C and "Auto" is set on , Climatronic Control Module J255. Temperature must be set such on , Climatronic Control Module J255 that air conditioner is in heating mode and temperature measured by sensors (Left Vent Temperature Sensor G150 , Right Vent Temperature Sensor G151) must not exceed + 35°C. Depending on the outside temperature, heating period is a maximum of 6 minutes (at -40°).
2. On selecting "Defrost" mode on , Climatronic Control Module J255 if outside temperature is less than + 5°C.Depending on the exterior temperature, the heating period is between 2 and 6 minutes. As long as heated windshield is switched on, switch-on indicator lamp in Defrost button flashes. Actuation only takes place with engine running.

1. Heated Windshield Control Module J505 - A - switches on heated windshield if the following conditions are met.

1. Climatronic Control Module J255 actuates Heated Windshield Control Module J505.
2. Voltage at Heated Windshield Control Module J505 is greater than 12.70 V.
3. Heated Windshield Control Module J505 is not overheated

1. Heated Windshield Control Module J505 is actuated by , Climatronic Control Module J255 via data wire. If a condition exists in Heated Windshield Control Module J505 which does not permit activation of windshield heater, , Climatronic Control Module J255 is informed via this data wire that heated windshield will be not be activated. Vehicle Diagnosis, Testing and Information System VAS 5051 in "Guided Fault Finding" function.
2. Electrical resistance of metal foil in heated windshield Z2 is approx. 1.9 Ohm. A voltage greater than the electrical system voltage is needed in order to reach the maximum possible heat output of approx. 1000 W (Watt) on the front window. Heated Windshield Control Module J505 for Heated Windshield Z2 converts electrical system voltage into a variable voltage of between 25 and 48 V, depending on electrical system voltage. If voltage at Heated Windshield Control Module J505 is greater than 13.10 V, Heated Windshield Z2 is actuated with voltage greater than 41 V (up to max. 48 V).
3. To prevent electrical system overload, Heated Windshield Control Module J505 regulates heating output of heated windshield. At vehicle voltage of 12.70 V, output is approx. 200 W and is gradually increased up to 1000 W at 13.10 volt. To prevent vehicle electrical system from collapsing when heated windshield is switched on, Heated Windshield Control Module J505 allows for an output increase of 200 W per second.
4. To prevent actuation of Heated Windshield Z2 in the event of short circuit or open circuit in wiring, Heated Windshield Control Module J505 checks resistance of Heated Windshield Z2. If measured resistance is less than approx. 1.5 ohms (short circuit) or greater than approx. 3.3ohms (open circuit or contact resistance), Heated Windshield Control Module J505 does not switch on or off heater.

Pump valve unit operation, checking

In this test, function of pump valve unit (Left Heat Regulating Valve N175 , Right Heat Regulating Valve N176 and Coolant Pump V50) is checked.

1. If the determined temperatures lie below the specification (heating performance too low)

1. Check operation of Left Heat Regulating Valve N175 , Right Heat Regulating Valve N176 and Coolant Pump V50 OK? Vehicle Diagnosis, Testing and Information System VAS 5051 in "Guided Fault Finding" function.

If no malfunctions are detected

1. Check for interchanged coolant hoses (from engine to pump valve unit or from pump valve unit to heater cores of air conditioner) --> «Pump/valve unit, removing and installing»(ref-289225-S19938788502008062700000) and --> «19 - ENGINE - COOLING SYSTEM»(ref-289203-S15357943982008062700000) for 4.2 LITER V8 4V ENGINE MECHANICAL, ENGINE CODE(S): BVJ 19 - ENGINE - COOLING SYSTEM for 4.2 LITER V8 5V ENGINE MECHANICAL, ENGINE CODE(S): BFM «19 - ENGINE - COOLING SYSTEM»(ref-289204-S03664241582008062700000) for 5.2 LITER 10-CYL. 4V ENGINE MECHANICAL, ENGINE CODE(S): BSM «19 - COOLING SYSTEM»(ref-289206-S27114819052008062700000) for 6.0 LITER 12-CYL. 4V ENGINE MECHANICAL, ENGINE CODE(S): BSB
2. Check for interchanged electrical terminals of Coolant Pump V50 of pump valve unit (direction of pump operation). --> Electrical Wiring Diagrams, Troubleshooting and Component Locations