On Board Diagnostic (OBD) Audi A4 B6

Note. The A/C control head -E87- exists in different versions. Follow coding procedure exactly when replacing an A/C control head -E87- On this vehicle the diagnostic connections of various control modules (e.g. Radio) has been routed to a different pin on the Data Link Connector (DLC). In order to exchange data with these control modules, the VAS 6017 adapter must be connected between the VAS 5051 and the vehicle. See appropriate System Wiring Diagrams article. In order to carry out the On Board Diagnostic (OBD) on this vehicle using the VAG 1551 or VAG 1552, it is necessary that program card no. 9 is installed in the VAG 1551 and card no.6 is installed in VAG 1552.

Equipment

1. DTC memory is designed for permanent memory and is therefore not dependent on voltage supply.
2. Data is transmitted between the A/C control head -E87- and the VAS 5051 tester, VAG 1551 Scan Tool (ST) or VAG 1552 system tester via operating mode "Rapid Data Transfer".

Function

The AC control head -E87- is a equipped with a DTC memory.

After evaluation, the A/C control head -E87- differentiates between different malfunctions (see DIAGNOSTIC TROUBLE CODE (DTC) TABLE ) and saves those malfunctions until DTC memory is erased.

When malfunctions occur in monitored sensors or components, Diagnostic Trouble Codes (DTCs) are stored in DTC memory with a description of the malfunction type.

Initiate On Board Diagnostic (OBD) at the beginning of the troubleshooting procedure and check DTC memory. To check saved information the following equipment is available

1. VAS 5051 Vehicle Diagnostic, Testing and Information System
2. VAG 1551 Scan Tool (ST)
3. VAG 1552 Scan Tool

The stored DTCs can be compared to a DTC table with notes regarding potential malfunction causes and specific repair procedures.

Note. A malfunction will be stored as static malfunction, when a malfunction condition exists longer than a certain (predetermined) time. The malfunction will stored as a sporadic DTC, if the malfunction condition no longer exists in a predetermined time. The procedure repeats itself constantly. Sporadically occurring malfunctions are identified via indication of "ISP" on the display. A sporadic malfunction is erased automatically if it no longer occurs after a certain predetermined time.

The full OBD capability can only be accessed via the VAS 5051 Vehicle Diagnostic, Testing and Information System, VAG 1551 Scan Tool or VAG 1552 system tester, using operating mode "Rapid Data Transfer".

The On Board Diagnostic (OBD) is not just limited to saving, checking and erasing DTCs or to output diagnostic test mode, but also can set basic settings, perform control module identification and input coding as additional options.

Operating mode -2- (blink code output) is not available for A/C heating electronics. Operating modes -3- (self test) and -4- can be used by the VAG 1551 Scan Tool or VAG 1552 system tester and are described in the relevant operating manuals.

Scheme 1

Note. The following numbered list refers to footnote references in (Scheme 1).

1. During the OBD the control module version is always displayed on the VAS 5051
2. Output Diagnostic Test Mode can only be carried out up to an engine speed of 3000 RPM and a vehicle speed less than 5 km/h. The A/C Compressor Regulator Valve -N280- is only activated by the A/C control head -E87- when the engine is not running. The request to activate the coolant fan (1 - 100%) is sent by the A/C control head -E87- to the Engine Control Module (ECM) via the CAN-bus comfort system. The control module switches the coolant fans on, but only with the engine running. See VAS 5051 Vehicle Diagnostic Testing and Information System
3. The basic setting codes for the A/C control head -E87- occurs on this vehicle through the instrument cluster. The data is transmitted to the A/C control head -E87- via the CAN-bus comfort system, the currently valid coding is shown in the measuring value block, see «READ MEASURING VALUE BLOCK (FUNCTION 08)»(/audi/a4/b6-2000-2006/remont/communication-devices/#on-board-diagnostic-obd__read-measuring-value-block-function-08) . The direct coding input into the A/C control head -E87- applies to certain options (e.g. windshield defroster). See VAS 5051 Vehicle Diagnostic Testing and Information System
4. During the initial operation of the A/C control head -E87-, the Vehicle Identification Number (VIN) transmitted by the CAN-bus comfort system is saved. If the -E87- is to be installed in another vehicle, the VIN must be erased via the "Adaptation" function.

Note. In this Repair Manual the On Board Diagnostic (OBD) is described with the VAS 5051 Vehicle Diagnostic, Testing and Information System. The OBD can be carried out in the same fashion using VAG1551 Scan Tool or VAG1552 system tester. In order to show or explain a possible malfunction(s) later on, it is recommended to print out the malfunction using the VAS 5051 Vehicle Diagnostic, Testing and Information System or VAG 1551 before erasing the DTC memory ((VAG 1552 system tester is not equipped with a printer). If a new A/C control head -E87- has been installed and the "Basic Setting" was not carried out, the A/C Compressor Regulator Valve -N280- will not be activated and the compressor cut-off condition "6" is displayed in read measuring value block, display group 002. When the OBD is started, the control functions on the climate control are not interrupted, however they will be switched off during the following functions

1. Output Diagnostic Test Mode (DTM)
2. Initiate basic setting

When selecting other functions the control function remains completely functional.

1. Component location, see «A/C SYSTEM CONTROL AND REGULATION COMPONENTS»(/audi/a4/b6-2000-2006/remont/automatic-hvac-system/#air-conditioning) .

Safety precautions

If special testing equipment is required during road test, note the following

Test requirements

1. Voltage supply for vehicle is OK.
2. Fuses OK

See appropriate System Wiring Diagrams article

Note. The various functions of the VAS 5051 Vehicle Diagnostic, Testing and Information System are described in the instruction manual. The structure and function of the VAS 5051 Vehicle Diagnostic, Testing and Information System is described in the self-study program no.202. In this self-study program, you will find several examples for the correct application of this system. For this vehicle the diagnostic connections of various control modules (e.g. Radio) has been routed to a different pin on the Data Link Connector (DLC). In order to exchange data with these control modules, the VAS 6017 adapter must be connected between the VAS 5051 and the vehicle. See appropriate System Wiring Diagrams article The OBD can also be carried out using VAG1551 Scan Tool or VAG1552 system tester in operating mode "Rapid Data Transfer". The various functions for these systems are described in the pertaining owners manuals. In order to carry out the On Board Diagnostic (OBD) on this vehicle using the VAG 1551 or VAG 1552, it is necessary that program card no. 9 is installed in the VAG 1551 and card no.6 is installed in VAG 1552.

Scheme 2

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Scheme 5

1. With ignition switched off connect VAS 5051 Vehicle Diagnostic, Testing and Information System with VAS 5051/1 diagnostic cable to 16-pin Data Link Connector (DLC) on vehicle.
2. Switch ignition on.
3. Start engine. NOTE: Observe notes for output Diagnostic Test Mode, see «OUTPUT DIAGNOSTIC TEST MODE (DTM) (FUNCTION 03)»(/audi/a4/b6-2000-2006/remont/communication-devices/#on-board-diagnostic-obd__output-diagnostic-test-mode-dtm-function). If OBD has to be carried out on several vehicle systems, use VAG 6017 adapter. The LEDs on VAG 6017 light up, as soon as the vehicle system tester sends a request and as soon as the vehicle control module answers or informs on which channel (1 or 2) the information is transferred.
4. Select "Auto" operating mode on A/C Control Head -E87
5. Select "Vehicle Self Diagnostic" function on VAS 5051.
6. Select vehicle system "08 - AC heater electronics". NOTE: Display field -1- shows request to select vehicle system Use scroll bar -2- on screen to display vehicle systems (for all vehicle models and equipment) that apply to the self diagnostic and also systems that cannot be displayed currently.
7. Wait until "Select diagnostic function"appears in display field -1- on VAS 5051 screen. NOTE: Display field -2- of VAS 5051 now displays the control module identification => «CONTROL MODULE IDENTIFICATION (E.G. IN DISPLAY FIELD -2-)»(/audi/a4/b6-2000-2006/remont/communication-devices/#on-board-diagnostic-obd) If "Vehicle system not available" is shown in display field -1- on VAS 5051 screen, check
8. Voltage supply to A/C control head -E87- according to wiring diagram. See appropriate System Wiring Diagrams article
9. The wire connection between the 16-pin Data Link Connector (DLC) and the A/C control head -E87-. If an additional display field -2- "Diagnostic Bus interrupted" appears and with notes for a possible malfunction cause on the VAS 5051 display, check
10. The voltage supply to the 16-pin Data Link Connector (DLC) according to wiring diagram See appropriate System Wiring Diagrams article
11. Voltage and condition of vehicle battery See VAS 5051 Vehicle Diagnostic Testing and Information System The display "Diagnostic Bus interrupted" with notes of a possible malfunction cause on VAS 5051 display appears also when an interference occurred or the data exchange between VAS 5051 and -E87- has been interrupted during the on board diagnostic The current VAS 5051 screen can be printed out, by selecting the "PRINT" function. The possible malfunction causes can be displayed, by selecting the "Help" function on the VAS 5051 display. By clicking on the arrow buttons on the VAS 5051 display, you can advance or return in the program or change functions.
12. Via the VAS 5051 display you can start the desired function, see Table "Function selection" (Scheme 1)

Scheme 6

1. 08-AC Heating Electronics Selected vehicle system
2. 8E0 820 043 X Part number; allocation
3. A4 Klimaautomat Audi A4 A/C control module (Klimaautomat = automatic climate control system)
4. XXXX Data version (hard and software version) of control module
5. Coding XXXXX: Applies to applicable vehicle options. See «A/C CONTROL HEAD -E87-, CODING (FUNCTION 07)»(/audi/a4/b6-2000-2006/remont/communication-devices/#on-board-diagnostic-obd__ac-control-head-e87-coding-function)
6. WSC XXXXX: Dealer identification number of dealer with which the last coding was performed.

Note. As of April 2002, there will be a running change to installing A/C Control Head -E87- with part numbers from index "H" (with hardware/software version from "XX15"). The -E87-, temperature control is designed for slightly cooler performance for passenger compartment. For vehicles as of model year 2003, only A/C Control Head -E87- with part number from index "H" is/will be installed. The A/C Control Head -E87- switches automatically to "Econ" operating mode, if the basic setting has not been carried out after replacing E87, or the measured pressure of High Pressure Sensor -G65- is too low or too high (compressor should not be switched on); Read measuring value block. See READ MEASURING VALUE BLOCK (FUNCTION 08) . This condition is stored as a malfunction in the DTC memory. If the A/C control module -E87- automatically changes into operating mode "Off" after the ignition was switched on and with the ignition switched on, only the operating mode "Def" can be selected (other selections are not possible). In this case, (for example) the ignition has been switched on with a key, that is not enabled for this vehicle or the control module in the instrument cluster does not send the key number via the CAN-bus comfort system, the function of -E87- is reduced in this mode. The A/C control head -E87- saves the Vehicle Identification Number (VIN) transmitted by the CAN-bus comfort system. If an A/C control head -E87- which was already once installed is installed into another vehicle, the -E87- recognizes this and stores the malfunction "Control module incorrect VIN". If this malfunction is displayed, erase old VIN via the "Adaptation" function. See ADAPTATION OF VEHICLE IDENTIFICATION NUMBER (VIN), PERFORMING (ADAPTATION CHANNEL 81) . For the Audi Cabriolet, different settings for closed and open convertible top are stored in the A/C Control Head -E87-. When opening and closing the convertible top, the A/C Control Head -E87- independently changes the setting to the value which was last adjusted during closed or open convertible top.

Diagnostic Trouble Code (DTC) Memory, checking (function 02)

Note. The A/C Control Head -E87- switches automatically to "Econ" operating mode, if the basic setting has not been carried out after replacing E87, or the measured pressure of High Pressure Sensor -G65- is too low or too high (compressor should not be switched on), see READ MEASURING VALUE BLOCK (FUNCTION 08) . This condition is stored as a malfunction in the DTC memory. If the A/C control module -E87- automatically changes into operating mode "Off" after the ignition was switched on and with the ignition switched on, only the operating mode "Def" can be selected (other selections are not possible). In this case, (for example) the ignition has been switched on with a key, that is not enabled for this vehicle or the control module in the instrument cluster does not send the key number via the CAN-bus comfort system.

1. With ignition switched off connect VAS 5051 Vehicle Diagnostic, Testing and Information System with the VAS 5051/1 diagnostic cable to the 16-pin diagnostic connector on the vehicle and select address word "08 - A/C heater/electronics". See «VAS 5051 VEHICLE DIAGNOSTIC, TESTING AND INFORMATION SYSTEM, CONNECTING AND SELECTING FUNCTIONS»(/audi/a4/b6-2000-2006/remont/communication-devices/#on-board-diagnostic-obd) .

Indicated on display of VAS 5051

Scheme 7

1. Select "02 - Check DTC memory" function.

Indicated on display of VAS 5051

Scheme 8

1. Display field -1- indicates the number of stored malfunctions.
2. Display field -2- indicates the DTC, the malfunction location and malfunction type of the saved malfunction. NOTE: By clicking the --> button, you will return to the selection menu.
3. If no malfunction is recognized, yet the climate control system does not operate properly (e.g. continuous or sporadic no cooling performance, system control is insufficient, fresh air blower speed cannot be regulated or the -E87- always switches into "Econ" or "Off" mode): Read measuring value block (function 08). See «READ MEASURING VALUE BLOCK (FUNCTION 08)»(/audi/a4/b6-2000-2006/remont/communication-devices/#on-board-diagnostic-obd__read-measuring-value-block-function-08) Carry out output Diagnostic Test Mode (DTM) (function 03). See «OUTPUT DIAGNOSTIC TEST MODE (DTM) (FUNCTION 03)»(/audi/a4/b6-2000-2006/remont/communication-devices/#on-board-diagnostic-obd__output-diagnostic-test-mode-dtm-function) Check cooling performance of climate control system. See «A/C REFRIGERANT SYSTEM COOLING PERFORMANCE, TESTING»(/audi/a4/b6-2000-2006/remont/automatic-hvac-system/#air-conditioning) .
4. If malfunction were recognized: Repair malfunction. Check DTC memory (function 02) Erase DTC memory (function 05) Check coding of A/C Control Head -E87- or instrument cluster. See «A/C CONTROL HEAD -E87-, CODING (FUNCTION 07)»(/audi/a4/b6-2000-2006/remont/communication-devices/#on-board-diagnostic-obd__ac-control-head-e87-coding-function) Carry out function 04, basic setting Check DTC memory (function 02) and if necessary eliminate displayed malfunctions, erase DTC memory (function 05) and repeat procedure. End Output (function 06).

Indicated on display of VAS 5051

Scheme 9

1. End Output (function 06). See «END OUTPUT (FUNCTION 06)»(/audi/a4/b6-2000-2006/remont/communication-devices/#on-board-diagnostic-obd) .
2. Switch off ignition and disconnect diagnostic cable.

Diagnostic Trouble Code (DTC) table

Note. Afterward, all possible malfunctions that are recognized by the A/C control head -E87- and displayed on the VAS 5051 during the checking procedure, are listed according to DTCs. The contents of the DTC memory remain stored until the memory is erased. See DIAGNOSTIC TROUBLE CODE (DTC) MEMORY, ERASING (FUNCTION 05) . Sporadic malfunctions are displayed as "/SP". When dealing with any sporadic DTCs, always pay attention to possible loose terminals in harness connectors. Before replacing a component that was shown as malfunctioning, check wiring and connections to the component for short circuit and open circuit according to the relevant wiring diagram. See appropriate System Wiring Diagrams article Before replacing components check the relevant harness connectors. Before replacing the A/C control head -E87- check also the voltage supply and Ground (GND) connections: See appropriate System Wiring Diagrams article If the A/C control head -E87- remains operational although the ignition is switched off, check wiring connection of -E87- harness connector D, terminal 10 for short circuit to B+. For the Audi Cabriolet, different settings for closed and open convertible top are stored in the A/C Control Head -E87-. When opening and closing the convertible top, the A/C Control Head -E87- independently changes the setting to the value which was last adjusted during closed or open convertible top. Always carry out the "Basic Setting" (function 04) after replacing climate control system components. Afterward check DTC memory, eliminate and erase all possible displayed malfunctions (function 02 and 05). The display can be changed from °C (Celsius) to °F (Fahrenheit) and vice-versa by pressing the button" Temperature + left"while simultaneously holding down the recirculated air button. See A/C CONTROL HEAD -E87-, REMOVING AND INSTALLING . Check cooling performance of air conditioning system. See A/C REFRIGERANT SYSTEM COOLING PERFORMANCE, TESTING . If the compressor output has been reduced 30 times during a driving cycle due to an incorrect pressure in the refrigerant circuit, e.g. because of a loose contact (in wiring connection to High Pressure Sensor -G65-), the A/C Compressor Regulator Valve -N280- is then no longer activated and the compressor is therefore switched off. The compressor can be switched on again by pressing the "AUTO" button, or by switching the ignition off and on again. If a malfunction is detected in the potentiometer of one of the air distribution positioning motors, the air distribution can be changed by pressing the buttons of the A/C Control Head -E87-. Check the following, if a malfunctioning temperature control has been detected and no malfunction is displayed: Correct installation of temperature sensor. Reversed wiring to Sunlight Photo Sensor -G107- Function of Interior Temperature Sensor Fan -V42- (implemented in A/C Control Head -E87-). Activation of both temperature flaps via the relevant actuator motors. If the DTC memory is checked with the VAG 1551 or VAG 1552, for certain malfunction types there is no text display (malfunction text will not be implemented in program card for this scan tool).

Scheme 10

Note. On this vehicle the coding of the basic setting (e.g. country variants etc.) is carried out in the instrument cluster and is transferred to the connected vehicle systems via the CAN-bus comfort system, the current valid coding is displayed in the read measuring value block. See READ MEASURING VALUE BLOCK (FUNCTION 08) . The direct input of a code into the A/C control head -E87- applies to certain equipment (e.g. windshield defroster, model type Sedan, Avant or Convertible. See A/C CONTROL HEAD -E87-, CODING (FUNCTION 07) .

See VAS 5051 Vehicle Diagnostic Testing and Information System

Scheme 11

Scheme 12

Note. The reception of information is displayed in Read Measuring Value Block (display group 125). See MEASURING VALUE BLOCKS 001 TO 010 .

Scheme 13

Scheme 14

Note. The reception of information is displayed in Read Measuring Value Block (display group 125). See MEASURING VALUE BLOCKS 001 TO 010 .

Scheme 15

Note. The Anti-Theft Engine Disable Control Module -J334- is integrated into the Control module with indicator unit in instrument cluster -J285-. If the ignition has been switched on with a key that was not enabled for the vehicle, the A/C Control Head -E87- switches automatically to "Off" mode after the ignition is switched on, and with the ignition switched on the -E87- can only be switched to "Def" mode (other adjustments are not possible).

Scheme 16

Note. If the voltage value of the vehicle electrical system (connector -C-, terminal -13-) drops below 9.5 volt, e.g. the Heated rear window -Z1-, Drivers Seat Heating Element -Z6- and Passengers Seat Heating Element -Z8- are switched off. In the event that the battery was charged with an incorrect battery charger, the malfunction "Signal too high" can also be displayed.

Scheme 17

Note. The malfunction "adaptation limit exceeded" is only recognized during basic setting. If this malfunction is stored, a substitute value will be stored as an adaptation value (learned value for this potentiometer) and will be displayed in the respective measuring block. If malfunction "adaptation limit exceeded" is displayed, check whether the flap reaches both limits stops and that both activation levers do not have excessive play (worn out).

Scheme 18

Scheme 19

Note. The malfunction "adaptation limit exceeded" is only recognized during basic setting. If this malfunction is stored, a substitute value will be stored as an adaptation value (learned value for this potentiometer) and will be displayed in the respective measuring block. If malfunction "adaptation limit exceeded" is displayed, check whether the flaps reach both limits stops and that the activation levers have no excessive play (worn out).

Scheme 20

Scheme 21

Note. The Recirculation Flap Motor -V113- only moves the recirculated air flap, the back pressure/fresh air flaps are moved by Air Flow Flap Motor -V71-.

Scheme 22

Note. The malfunction "adaptation limit exceeded" is only recognized during basic setting. If this malfunction is stored, a substitute value will be stored as an adaptation value (learned value for this potentiometer) and will be displayed in the respective measuring block. If malfunction "adaptation limit exceeded" is displayed, check whether the flap reaches both limits stops and that both activation levers do not have excessive play (worn out).

Scheme 23

Note. The malfunction "adaptation limit exceeded" is only recognized during basic setting. If this malfunction is stored, a substitute value will be stored as an adaptation value (learned value for this potentiometer) and will be displayed in the respective measuring block. If malfunction "adaptation limit exceeded" is displayed, check whether the flap reaches both limits stops and that both activation levers do not have excessive play (worn out). The Recirculation Flap Motor -V113- only moves the recirculated air flap, the back pressure/fresh air flaps are moved by Air Flow Flap Motor -V71-.

Scheme 24

Scheme 25

Note. The Instrument Panel Interior Temperature Sensor -G56- is integrated in the A/C control head -E87-. -G56- cannot be checked or replaced individually, if malfunctioning replace -E87- completely.

Scheme 26

Scheme 27

Note. The Interior Temperature Sensor Fan -V42- is integrated in the A/C control head -E87-. Interior Temperature Sensor Fan - V42- cannot be checked or replaced individually, if malfunctioning replace -E87- completely. The RPM of Interior Temperature Sensor Fan -V42- measured by the A/C control head -E87- is displayed in measuring value block (display field 011). See READ MEASURING VALUE BLOCK (FUNCTION 08) .

Scheme 28

Note. Sunlight Photo Sensor -G107- contains two photo transistors (separate for driver and passenger side).

Scheme 29

Note. If a malfunction is recognized at Evaporator Vent Temperature Sensor -G263-, the A/C Control Head -E87- switches into emergency mode, therefore the A/C Compressor Regulator Valve -N280- is activated at the time with a maximum control current of 0.3 - 0.5 A (the cooling performance of the climate control is less and is at higher temperature not efficient enough). See READ MEASURING VALUE BLOCK (FUNCTION 08) (display group 001 and 002).

Scheme 30

Scheme 31

Note. The transferred duty cycle of High Pressure Sensor -G65- is displayed in measuring value block (display group 001). See READ MEASURING VALUE BLOCK (FUNCTION 08) . The ambient conditions under which the pressure in the refrigerant was last not OK, are displayed in measuring value block (display group 026 and 027). See READ MEASURING VALUE BLOCK (FUNCTION 08) . The A/C Control Head -E87- switches automatically to "Econ" if the pressure measured by the High Pressure Sensor - G65- is too low or too high (compressor should not be switched on). See READ MEASURING VALUE BLOCK (FUNCTION 08) .

Scheme 32

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Scheme 41

Note. If the Basic setting was not carried out after the A/C control head -E87- has been replaced, the -E87- switches automatically to "Econ" mode.

Scheme 42

Scheme 43

Note. If no signal for the "ignition off" period is detected by the A/C Control Head -E87- when the ignition is switched on (the signal comes from the instrument cluster via the CAN-bus comfort system), the A/C Control Head -E87- assumes that the vehicle has been left standing for more than 4 hours, and the engine temperature is assumed to be identical to the ambient temperature. If the system is in heating mode, there may be a delay before the fresh air blower switches on, even though the engine is warm. The outside air temperature display -G106- in the instrument cluster may also display incorrect ambient temperature values.

Scheme 44

Scheme 45

Scheme 46

Note. The regulator valve is integrated in the compressor

See COMPONENTS IN ENGINE COMPARTMENT AND REAR OF VEHICLE

Scheme 47

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Scheme 50

Note. The Control module for fresh air blower -J126- is integrated in the Fresh Air Blower -V2-, and cannot be replaced separately. The status of the fresh air blower is displayed in measuring value block (display group 018), via this status display the - E87- is informed by the Control module for fresh air blower -J126-, in case -V2- has a malfunction. See READ MEASURING VALUE BLOCK (FUNCTION 08) . In the event that the battery was charged with an incorrect battery charger, the malfunction "Signal too high/SP" can also be displayed.

Scheme 51

Scheme 52

Note. For example; if the engine control module does not send the current engine speed information (via CAN-bus system), the control module in the instrument cluster cannot place this information on the CAN-bus comfort system and this malfunction is stored in the DTC memory of -E87-.

Scheme 53

Scheme 54

Note. The reception of the information is displayed in Read Measuring Value Block (display group 125). See READ MEASURING VALUE BLOCK (FUNCTION 08) .

Scheme 55

Note. The malfunction location "Multi-function Unit Control Module -J501-" instead of "Vehicle Electrical System Control Module - J519-" was stored in the software on some A/C control heads -E87-.

Scheme 56

Note. The malfunction location "Control module for multi-function steering wheel -J453-" instead of "Steering Column Electronic Systems Control Module" was stored in the software on some A/C control heads -E87-.

Scheme 57

Scheme 58

Note. The reception of the information is displayed in Read Measuring Value Block (display group 125). See READ MEASURING VALUE BLOCK (FUNCTION 08) .

Scheme 59

Scheme 60

Scheme 61

Note. The reception of the information is displayed in Read Measuring Value Block (display group 125). See READ MEASURING VALUE BLOCK (FUNCTION 08) .

Scheme 62

Note. Under certain circumstances sporadic malfunctions can be stored for Sensor for air quality -G238-, this can be caused by radio wave rays (e.g. amateur radio or police radio). However since these malfunction do not interfere with the function of A/C Control Head -E87-, erase this malfunction if necessary.

Scheme 63

Note. If the A/C Control Head -E87- is coded with Heated front window -Z2-, although the vehicle has no Heated front window - Z2-, the malfunction "Open/short to Ground" or "Short to B+" is stored (depending on software level of -E87-).

Scheme 64

Note. A new A/C Control Head -E87- is shipped as a replacement part without VIN coding. When the ignition is switched on for the first time after installing, the transferred VIN is imported and saved into -E87- (anti-theft protection). The VIN stored in the A/C control head -E87- is shown in display group "081". See DISPLAY GROUP 081 (function "Read Measuring Value Block" display group 081). If an A/C control head -E87- is installed into a different vehicle, the transmitted and saved VIN no longer matches and the malfunction "control module incorrect VIN" is stored in the -E87-. The VIN saved in A/C Control Head -E87- will be erased by entering the PIN-number in the "Adaptation" function. See ADAPTATION OF VEHICLE IDENTIFICATION NUMBER (VIN), PERFORMING (ADAPTATION CHANNEL 81) .

Scheme 65

Scheme 66

Scheme 67

Note. The malfunction "adaptation limit exceeded" is only recognized during basic setting. If this malfunction is stored, a substitute value will be stored as an adaptation value (learned value for this potentiometer) and will be displayed in the respective measuring block. If malfunction "adaptation limit exceeded" is displayed, check whether the flap reaches both limits stops and that both activation levers do not have excessive play (worn out).

Scheme 68

Note. The malfunction "adaptation limit exceeded" is only recognized during basic setting. If this malfunction is stored, a substitute value will be stored as an adaptation value (learned value for this potentiometer) and will be displayed in the respective measuring block. If malfunction "adaptation limit exceeded" is displayed, check whether the flap reaches both limits stops and that both activation levers do not have excessive play (worn out).

Scheme 69

Output Diagnostic Test Mode (DTM) (function 03)

Note. Observe the following for the output Diagnostic Test Mode (DTM)

1. The A/C Compressor Regulator Valve -N280- is only activated by the A/C control head -E87- when the engine is not running.
2. The request to activate the coolant fans (step 1 and 2) is always transmitted by the A/C control head -E87- to the Engine Control Module (ECM). The engine control module switches the coolant fans on, but only with the engine running. See «MULTIPORT FUEL INJECTION (MFI), GENERIC SCAN TOOL - 3.0L AVK»(/audi/a4/b6-2000-2006/remont/fuel-system/#multiport-fuel-injection-mfi-generic-scan-tool-30l-avk) . See «MULTIPORT FUEL INJECTION (MFI) -1.8L 5V TURBO, AMB»(/audi/a4/b6-2000-2006/remont/fuel-system/#multiport-fuel-injection-mfi-18l-5v-turbo-amb) - The output Diagnostic Test Mode can only be carried out up to an engine speed of 3000 RPM and a vehicle speed less than 5 km/h. Component location of activated components, see «A/C SYSTEM CONTROL AND REGULATION COMPONENTS»(/audi/a4/b6-2000-2006/remont/automatic-hvac-system/#air-conditioning) . The Output Diagnostic Test Mode (DTM) can be carried out more than once if necessary. Malfunctions on the actuators are stored in the DTC memory. The control and the display of the A/C control head -E87- is switched off during the output Diagnostic Test Mode. The segments of the A/C control head -E87- are only activated during the "Segment test" function. After selecting the "output Diagnostic Test Mode" function, the positioning motors of the climate control system are being moved into a pre-assigned position. During the output Diagnostic Test Mode, it is not necessary to wait until the positioning motors reach the pre-assigned position. For vehicles with 8 cyl. engine the compressor is driven by a shaft, rather than a belt. See «VEHICLES WITH 8 CYL. ENGINE (COMPRESSOR DRIVE VIA A SHAFT)»(/audi/a4/b6-2000-2006/remont/automatic-hvac-system/#air-conditioning__vehicles-with-8-cyl-engine-compressor) .

Initiating output DTM

1. With ignition switched off, connect VAS 5051 Vehicle Diagnostic, Testing and Information System with VAS 5051/1 diagnostic cable to 16-pin data link connector on vehicle. See «VAS 5051 VEHICLE DIAGNOSTIC, TESTING AND INFORMATION SYSTEM, CONNECTING AND SELECTING FUNCTIONS»(/audi/a4/b6-2000-2006/remont/communication-devices/#on-board-diagnostic-obd) .
2. Switch ignition on/Start engine. NOTE: Switch ignition on (to check the activation of A/C Compressor Regulator Valve -N280-, the engine should not be running) Start engine (to activate coolant fans)
3. Select "Auto" operating mode on A/C Control Head -E87
4. Select "Address word" 08 for A/C heater/electronics. See «VAS 5051 VEHICLE DIAGNOSTIC, TESTING AND INFORMATION SYSTEM, CONNECTING AND SELECTING FUNCTIONS»(/audi/a4/b6-2000-2006/remont/communication-devices/#on-board-diagnostic-obd) .
5. Open dash panel vents.
6. Check DTC memory. See «DIAGNOSTIC TROUBLE CODE (DTC) MEMORY, CHECKING (FUNCTION 02)»(/audi/a4/b6-2000-2006/remont/communication-devices/#on-board-diagnostic-obd__diagnostic-trouble-code-dtc-memory-checking) .

Indicated on display of VAS 5051

Scheme 70

1. Select "Output Diagnostic Test Mode (DTM)" function 03

Indicated on display of VAS 5051

1. Display field -1- shows which actuator is currently being activated (e.g. 1 actuator in test).
2. Display field -2 shows the actuators that were already activated one after the other or which one is currently activated. The actuator that is currently activated is displayed in the most lower line.

Scheme 71

1. By touching the --> button you can call up the next component to be tested. For function and sequence, see «ACTIVATED ACTUATORS»(/audi/a4/b6-2000-2006/remont/communication-devices/#on-board-diagnostic-obd) .

Note. By clicking the --> button you will return to the selection menu. Output DTM can be terminated by pressing the -C- button. When output DTM is completed, check DTC memory. See DIAGNOSTIC TROUBLE CODE (DTC) MEMORY, CHECKING (FUNCTION 02) . Check DTC memory when output DTM is aborted. See DIAGNOSTIC TROUBLE CODE (DTC) MEMORY, CHECKING (FUNCTION 02) and READ MEASURING VALUE BLOCK (FUNCTION 08) (display group 002).

Scheme 72

Note. The actuator "A/C Compressor Regulator Valve -N280-" is only actuated with engine switched off. This actuator will not be displayed on the VAS 5051 display and not activated by the A/C control head -E87- with the engine running. The regulator valve is integrated in the compressor. See COMPONENT OVERVIEW . The current that flows through the switched control valve can be measured using the current pick-up clamp. See AUTOMATIC CLIMATE CONTROL SYSTEM, ELECTRICAL TESTING . If another compressor cut-off condition exists besides "5 = engine speed less than 300 RPM", the "A/C Compressor Regulator Valve -N280-" will not be activated.

Scheme 73

Scheme 74

Note. Start engine when checking coolant fan activation. The Engine Control Module switches the coolant fans on, but only with the engine running. The request to switch on the Coolant fan -V7- is sent by the A/C control head -E87- to the respective ECM via the CAN-bus comfort system, the ECM then regulates the Coolant FC (Fan Control) Control Module -J293- with a square signal and the -J293- switches the coolant fans on.

Scheme 75

Note. Check function of Interior Temperature Sensor Fan -V42- with smoke (hold smoke before intake frame of A/C Control Head -E87-). The Interior Temperature Sensor Fan -V42- is part of A/C Control Head -E87- and cannot be replaced separately.

Scheme 76

Scheme 77

Scheme 78

Scheme 79

Note. The Recirculation Flap Motor -V113- only moves the recirculated air flap, the back pressure/fresh air flaps are moved by Air Flow Flap Motor -V71-.

Scheme 80

Note. The switch on function of A/C Control Head -E87- for heated rear window, e.g. can be checked during the output DTM using multimeter VAG 1715 or equivalent. Place current pick up clamp across B+ wire from A/C Control Head -E87- and heated rear window and select multimeter function "Current measurement with current pick up clamp". The display will change from approx. 0 amps to greater than 7 amps. If actuator "Windshield defroster" is displayed after actuator "Heated rear window", check coding of A/C Control Head - E87. See A/C CONTROL HEAD -E87-, CODING (FUNCTION 07) . A windshield defroster is currently not available, however, the A/C Control Head -E87- has already the possibility to activate this output via a possible coding.

Scheme 81

Note. If this actuator is activated on vehicles without windshield defrosters, check coding of A/C Control Head -E87-. See A/C CONTROL HEAD -E87-, CODING (FUNCTION 07) . The output DTM only activates the windshield defroster if the passenger compartment temperature is less than 40°C. If the temperature is higher, the text "Function unknown or cannot be carried out" is displayed on scan tool. The switch on function of Heated Windshield Control Module -J505- can be checked using multimeter VAG 1715 or equivalent. Place current pick up clamp across B+ wire from Heated Windshield Control Module -J505- and windshield defroster and select multimeter function to "Current measurement with current pick up clamp". The display will change from approx. 0 amps to greater than 7 amps. Function windshield defroster, see Read Measuring Value Block, display group 015. See READ MEASURING VALUE BLOCK (FUNCTION 08) and WINDSHIELD DEFROSTER, FUNCTION .

Scheme 82

Note. The activation for the heated seats occurs only on A/C control heads -E87- that are equipped with potentiometer for heated seats (observe part number and index). The switch on function of the heated seats can be checked using multimeter VAG 1715 or equivalent. Place current-pick up clamp across B+ wire of heated seat element and select multimeter function "Current measurement with current pick up clamp". The display will change from approx. 0 amps to greater than 2 amps.

Scheme 83

Note. The activation for the heated seats occurs only on A/C control heads -E87- that are equipped with potentiometer for heated seats (observe part number and index). The switch on function of the heated seats can be checked using multimeter VAG 1715 or equivalent. Place current-pick up clamp across B+ wire of heated seat element and select multimeter function "Current measurement with current pick up clamp". The display will change from approx. 0 amps to greater than 2 amps.

Basic Setting (function 04)

1. With ignition switched off connect VAS 5051 Vehicle Diagnostic, Testing and Information System with VAS 5051/1 diagnostic cable to 16-pin data link connector on vehicle and select address word "08 - A/C heater/electronics". See «VAS 5051 VEHICLE DIAGNOSTIC, TESTING AND INFORMATION SYSTEM, CONNECTING AND SELECTING FUNCTIONS»(/audi/a4/b6-2000-2006/remont/communication-devices/#on-board-diagnostic-obd)

Requirements

1. Check coding and correct if necessary. See «READ MEASURING VALUE BLOCK (FUNCTION 08)»(/audi/a4/b6-2000-2006/remont/communication-devices/#on-board-diagnostic-obd__read-measuring-value-block-function-08) (the current valid code will be shown in the Read Measuring Value Block) and «A/C CONTROL HEAD -E87-, CODING (FUNCTION 07)»(/audi/a4/b6-2000-2006/remont/communication-devices/#on-board-diagnostic-obd__ac-control-head-e87-coding-function) .
2. DTC memory checked. See «DIAGNOSTIC TROUBLE CODE (DTC) MEMORY, CHECKING (FUNCTION 02)»(/audi/a4/b6-2000-2006/remont/communication-devices/#on-board-diagnostic-obd__diagnostic-trouble-code-dtc-memory-checking) . For displayed malfunctions eliminated and DTC memory displayed, see «DIAGNOSTIC TROUBLE CODE (DTC) MEMORY, ERASING (FUNCTION 05)»(/audi/a4/b6-2000-2006/remont/communication-devices/#on-board-diagnostic-obd__diagnostic-trouble-code-dtc-memory-erasing) .
3. Control module with indicator unit in instrument panel insert -J285- is coded according to specification and adapted. See «A/C CONTROL HEAD -E87-, CODING (FUNCTION 07)»(/audi/a4/b6-2000-2006/remont/communication-devices/#on-board-diagnostic-obd__ac-control-head-e87-coding-function) .
4. Air conditioning switched ON (operating mode "Econ" or "Auto").

Basic setting

Indicated on display of VAS 5051

Scheme 84

1. Select "Basic setting" function 04

Indicated on display of VAS 5051

Scheme 85

1. Display field -1- indicates request to input display group.
2. Display field -2- shows input keyboard.

1. Input "01" or "001" in display field -2- for "display group number 001" and accept by pressing the -Q- button.

Indicated on display of VAS 5051

Scheme 86

The following positioning motors are now activated and the current feedback value will be shown in display field 1.

Currently the positioning motors are assigned as follows

Scheme 87

1. 1. place: Actuator for temperature flap left -V158
2. 2. place: Actuator for temperature flap right -V159- Indicated on display of VAS 5051
3. 3. place: Defroster Flap Motor -V107
4. 4. place: Central Air Flap Motor -V70
5. 5. place: Air Flow Flap Motor -V71
6. 6. place

Recirculation Flap Motor -V113

The coding entered in Control module with indicator unit in instrument panel insert -J285- is checked via Comfort databus and the settings designated for the A/C system are transferred, see A/C CONTROL HEAD -E87-, CODING (FUNCTION 07) and READ MEASURING VALUE BLOCK (FUNCTION 08) (the currently valid coding is displayed in the measuring value block).

The end positions of the positioning motors (resistance values at stop) are stored in the A/C control head -E87- (resistance value in potentiometer implemented in positioning motor) and utilized for additional controls.

After the positioning motors reached both limit stops, they are moved one more time from stop to stop. The adjustment time is measured during that move and stored in the A/C control head -E87-, in case an emergency mode is necessary at one time.

Indicated on display of VAS 5051

Scheme 88

The movement of the positioning motors can be monitored in display field -1- (the feed back values in display field 1 - 6 change).

Wait until display "0" for the displayed feed back values in display field -1- are shown.

Note. The basic setting is ended when "0" appears on the display. By clicking the --> button you will return to the selection menu. If a malfunction has been detected on one potentiometer during the Basic setting, a substitute value is stored as an adaptation value (learning value for this potentiometer) and is displayed in the respective measuring value block. The malfunction "Adaptation limit exceeded" is stored for this positioning motor. When initiating the Basic setting, the from the CAN-buscomfort system transmitted temperature unit is read and (=> F or °C) which is adjusted in the instrument cluster is accepted. The display on the A/C control head -E87- can be changed by simultaneously pressing the recirculated air button and the temperature + for left side button for more than 2 seconds. You can switch to another display group by touching button -2-. (Scheme 92) You can switch to another function (e.g. from "Basic setting to Read Measuring Value Block" and back) by touching button -3-.

1. Check DTC memory. See «DIAGNOSTIC TROUBLE CODE (DTC) MEMORY, CHECKING (FUNCTION 02)»(/audi/a4/b6-2000-2006/remont/communication-devices/#on-board-diagnostic-obd__diagnostic-trouble-code-dtc-memory-checking)
2. Erase DTC according to DTC table, after the last DTC has been displayed and printed. See «DIAGNOSTIC TROUBLE CODE (DTC) TABLE»(/audi/a4/b6-2000-2006/remont/communication-devices/#on-board-diagnostic-obd__diagnostic-trouble-code-dtc-table)

Note. Carry out the Basic Setting again in case a malfunction (DTC) was recognized and eliminated.

Diagnostic Trouble Code (DTC) Memory, erasing (function 05)

1. With ignition switched off connect VAS 5051 Vehicle Diagnostic, Testing and Information System with VAS 5051/1 diagnostic cable to 16-pin data link connector on vehicle and select address word "08 A/C heater/electronics". See «VAS 5051 VEHICLE DIAGNOSTIC, TESTING AND INFORMATION SYSTEM, CONNECTING AND SELECTING FUNCTIONS»(/audi/a4/b6-2000-2006/remont/communication-devices/#on-board-diagnostic-obd)

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

Procedure

Indicated on display of VAS 5051

Scheme 89

1. Select "Erase DTC Memory" function 05.

Indicated on display of VAS 5051

Scheme 90

1. No display appears in display field -1-.
2. A field is shown in display field -2- noticing that the data (of DTC memory) is erased when touching the "OK" button, and the question whether the function should be carried out or not.

Note. If "DTC memory has not been checked" is shown in display field -1-.

1. Check DTC memory.
2. If necessary eliminate any present malfunction(s). If ignition was switched off, e.g. between checking DTC memory and erasing DTC memory, then the DTC memory will not be erased.
3. Touch "OK" button on display field -2- "DTC memory erased" appears in display field -1- as soon as the DTC memory is erased.
4. Touch on the VAS 5051 screen the --> button.

1. DTC memory has been checked and erased, basic setting has been carried out and coding has been checked. See «A/C CONTROL HEAD -E87-, CODING (FUNCTION 07)»(/audi/a4/b6-2000-2006/remont/communication-devices/#on-board-diagnostic-obd__ac-control-head-e87-coding-function) .
2. The currently valid coding transmitted by the instrument cluster is displayed in the measuring value block. See «READ MEASURING VALUE BLOCK (FUNCTION 08)»(/audi/a4/b6-2000-2006/remont/communication-devices/#on-board-diagnostic-obd__read-measuring-value-block-function-08) ).

Indicated on display of VAS 5051

Scheme 91

Scheme 92

1. Select "06 - End output" function.
2. Wait until this display (menu) is shown on the VAS 5051 display.
3. Switch off ignition and disconnect diagnostic cable.

A/C control head -E87-, coding (function 07)

Note. The "base coding" of A/C Control Head -E87- for this vehicle is performed during Basic Setting of -E87- via Control module with indicator unit in instrument panel insert -J285-. The data is transmitted via the Comfort databus to -E87-, the currently valid coding is displayed in measuring value block. See READ MEASURING VALUE BLOCK (FUNCTION 08) (display group 019). Control module with indicator unit in instrument panel insert -J285- must be coded according to specification and adapted so that A/C Control Head -E87- is coded correctly. See . The direct coding input into the A/C control head -E87- applies for certain equipment. For example, if the Control module with indicator unit in instrument cluster has been coded to country variant "Japan", then when the recirculated air mode is selected before the ignition is switched off, the climate control will remain in recirculated air mode after the ignition has been switched off and on again.Ssee READ MEASURING VALUE BLOCK (FUNCTION 08) (display group 019). For the Audi Cabriolet, different adjustments for closed and open convertible top are stored in the A/C Control Head -E87-. When opening and closing the convertible top, the A/C Control Head -E87- independently changes the adjustment to the value which was last adjusted during closed or open convertible top.

Code control module

Note. The coding of control modules is only possible with test units that have a dealership number entered.

1. With ignition switched off connect VAS 5051 Vehicle Diagnostic, Testing and Information System with VAS 5051/1 diagnostic cable to 16-pin data link connector on vehicle and select address word "08-A/C heater/electronics", see «VAS 5051 VEHICLE DIAGNOSTIC, TESTING AND INFORMATION SYSTEM, CONNECTING AND SELECTING FUNCTIONS»(/audi/a4/b6-2000-2006/remont/communication-devices/#on-board-diagnostic-obd)

1. DTC memory checked, see «DIAGNOSTIC TROUBLE CODE (DTC) MEMORY, CHECKING (FUNCTION 02)»(/audi/a4/b6-2000-2006/remont/communication-devices/#on-board-diagnostic-obd__diagnostic-trouble-code-dtc-memory-checking) , displayed malfunctions eliminated and DTC memory displayed, see «DIAGNOSTIC TROUBLE CODE (DTC) MEMORY, ERASING (FUNCTION 05)»(/audi/a4/b6-2000-2006/remont/communication-devices/#on-board-diagnostic-obd__diagnostic-trouble-code-dtc-memory-erasing)
2. Air conditioning switched ON (operating mode "Auto").

Indicated on display of VAS 5051

Scheme 93

1. Select "07 -Code control module" function.

Indicated on display of VAS 5051

Scheme 94

Scheme 95

1. In display field -1- is the request to input the coding.
2. Display field -2- shows input keyboard.
3. Display field -3- shows in the fourth row the actual current code and in brackets the previously valid coding.
4. The fifth row of display field -3- shows the dealership number that was entered with the VAS 5051.

1. Code A/C control head -E87- according to the available equipment and vehicle type.
2. Coding table (Scheme 101)
3. Enter in keyboard field -2- the applicable coding according to the coding table.
4. Press -Q- button in display field -2- to confirm input.

After short time the VAS 5051 displays (Scheme 100)

Scheme 96

1. Display field -1- shows "Coding in vehicle system carried out"
2. Display field -2- indicates the control module identification with the new code and the old code in brackets.

Note. By clicking the -->button you will return to the selection menu. The malfunction message "Function unknown" or "Cannot be carried out at the moment" will be displayed if the coding was incorrect and the old coding remains. The A/C control head -E87- is coded with "00000" during manufacturing (delivered state as replacement part). The A/C control head -E87- is coded for different models via the vehicle variant coding

1. The "basic setting" comes in effect on Sedan, Avant and Coupe models.
2. On convertible models the function of heated rear window is switched over, the control characteristics changed respectively, and with the top open the control occurs via the vent temperature sensors.
3. On a Coupe model the control characteristics change respectively. The diagnostic and activation function of the windshield defroster is enabled, if the A/C control head -E87- is coded for a vehicle with Heated front window -Z2-. If the A/C control head -E87- is coded for a vehicle with sunroof with solar cells, the following adjustments are carried out on the climate control system after the ignition is switched off
4. The Actuator for temperature flap left -V158- and Actuator for temperature flap right -V159- are moved in the "cold" position.
5. The Central Air Flap Motor -V70- is moved to position "air to dash panel vents" and the defrost flap is closed via the Defroster Flap Motor -V107- (air in footwell).
6. The fresh air flap will be opened (Air Flow Flap Motor -V71-) and the recirculated air flap will be closed (Recirculation Flap Motor -V113-)

Read Measuring Value Block (function 08)

Note. To test speed signal push the vehicle several meters (more than 5 km/h) with the ignition switched on. Component locations of activated components, see A/C SYSTEM CONTROL AND REGULATION COMPONENTS .

1. With ignition switched off connect VAS 5051 Vehicle Diagnostic, Testing and Information System with VAS 5051/1 diagnostic cable to 16-pin data link connector on vehicle. See «VAS 5051 VEHICLE DIAGNOSTIC, TESTING AND INFORMATION SYSTEM, CONNECTING AND SELECTING FUNCTIONS»(/audi/a4/b6-2000-2006/remont/communication-devices/#on-board-diagnostic-obd) .
2. Switch ignition on or start engine.
3. Select "Auto" operating mode on A/C Control Head -E87
4. Select "Address word" 08 for A/C heater/electronics. See «VAS 5051 VEHICLE DIAGNOSTIC, TESTING AND INFORMATION SYSTEM, CONNECTING AND SELECTING FUNCTIONS»(/audi/a4/b6-2000-2006/remont/communication-devices/#on-board-diagnostic-obd) .

Indicated on display of VAS 5051

Scheme 97

1. Check DTC memory. See «DIAGNOSTIC TROUBLE CODE (DTC) MEMORY, CHECKING (FUNCTION 02)»(/audi/a4/b6-2000-2006/remont/communication-devices/#on-board-diagnostic-obd__diagnostic-trouble-code-dtc-memory-checking) .
2. Press buttons -0- and -8- to select "Read Measuring Value Block" function 08.

Indicated on display of VAS 5051

Scheme 98

1. Display field -1- indicates request to input display group.
2. Display field -2- shows input keyboard.

1. Input via the keyboard in display field -2- the desired display group (e.g. "001" or "01"), overview of display groups numbers which can be selected. See «OVERVIEW OF SELECTABLE DISPLAY GROUP NUMBERS»(/audi/a4/b6-2000-2006/remont/communication-devices/#on-board-diagnostic-obd) and accept by touching the Q-button.

Indicated on display of VAS 5051

Scheme 99

1. Display field -1- shows the selected display group.
2. Display field -2- shows the values of the four display fields: The value of display field -1- is shown in the first row. The second, third and fourth rows show the value of the respective display fields. If a display field is not assigned, no display occurs in this row.
3. By touching button -3- you can switch to another display group. (Scheme 105)
4. You can switch to another function (e.g. from "Basic setting" to "Read Measuring Value Block" and back) by touching button -4-.

Scheme 100

1. Input display group number; overview of display group numbers which can be selected. See «OVERVIEW OF SELECTABLE DISPLAY GROUP NUMBERS»(/audi/a4/b6-2000-2006/remont/communication-devices/#on-board-diagnostic-obd) .

Scheme 101

Scheme 102

Scheme 103

Scheme 104

Scheme 105

Scheme 106

Scheme 107

Scheme 108

Scheme 109

Scheme 110

Scheme 111

A/C Compressor Regulator Valve -N280- and High Pressure Sensor -G65

Note. If a compressor switch-off condition exists for the compressor (see display group 002) the A/C Compressor Regulator Valve -N280- cannot be activated during the output Diagnostic Test Mode (DTM) (see OUTPUT DIAGNOSTIC TEST MODE (DTM) (FUNCTION 03) ). The regulator valve cannot be activated if no signal is recognized by the High Pressure Sensor -G65-.

Scheme 112

Note. Display field 1 shows current strength that flows through A/C Compressor Regulator Valve -N280-. The current strength is calculated by A/C Control Head -E87-, the strength depends on the required coolant performance, the selected operating mode of -E87- and vehicle voltage. A pre-assigned minimum current must flow through regulator valve to ensure safe operation; on currently installed regulator valves this current is 0.3 amps. Depending on vehicle battery voltage a maximum current of 0.65 amps flows, when the regulator valve is fully activated (controlled and limited by A/C Control Head -E87-). If the pressure in refrigerant circuit (display field "3" and "4") does not change while the engine is running, even though the regulation valve is being activated with maximum voltage, check belt pulley or drive unit at compressor, the compressor must be driven (in case the overload fuse has activated, the belt pulley runs, however the compressor is not driven). See BELT PULLEY/DRIVE UNIT OF COMPRESSOR, REPLACING .

Scheme 113

Note. Display field 2 shows duty cycle for time in during which the current can actually flow. The A/C Control Head -E87- works with frequency of 500 Hz (500 Hertz = 600 switch impulses per seconds). The duty cycle indicates how great the activation time period is per impulse. The switch-on signal can be checked using with VAS 5051 using function "Test Instruments". See ENGAGEMENT SIGNAL FOR A/C COMPRESSOR REGULATOR VALVE -N280-, CHECKING . The duty cycle of A/C Control Head -E87- is selected in such a way that the specified evaporator temperature (depending on different influences) at the Evaporator Vent Temperature Sensor -G263- is obtained. See DISPLAY GROUP 009 . If a malfunction has been detected at the Evaporator Vent Temperature Sensor -G263-, the A/C Control Head -E87- switches to an emergency mode and the A/C Compressor Regulator Valve -N280- is activated with a pre-assigned maximum control current from -E87-. The maximum control current can be between approximately 0.3 A to 0.5 A, depending on the currently installed A/C Control Head -E87- version (however the cooling performance at lower or higher temperatures is not sufficient).

Scheme 114

Scheme 115

Note. Display field 3 shows the duty cycle of the time of signal when it is actually present. The A/C Control Head -E87- calculates the pressure in the refrigerant circuit via the duty cycle, the calculated pressure is shown in display field 4. When the duty cycle is smaller than 12% (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 smaller than 48% (corresponds to 16 bar absolute pressure). 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 16 bar). -As soon as the coolant temperature reaches 115°C (at 118°C compressor is switched off completely). Depending on the duty cycle, the A/C control head -E87- sends a signal to Engine Control Module (ECM) via the CAN-bus comfort system, so the ECM can switch the coolant fans on via the Coolant FC (Fan Control) Control Module -J293-. 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 and therefore the duty cycle depends on different influencing variables. However, at maximum compressor performance and an ambient temperature between 20 to 25°C the pressure should not exceed more than 20 bar (absolute pressure). Pressures up to 30 bar (absolute pressure) may occur under extreme operating conditions (e.g. in southern countries with high ambient temperatures, "stop and go" traffic and high humidity) due to high coolant performance. The High Pressure Sensor -G56- operates with a frequency of 50 Hz (50 Hertz = 50 activation impulse per second). The duty cycle indicates how great the activation time period is per impulse. The activation signal can be checked with VAS 5051 using function "Test Instruments". See PRESSURE SIGNAL FROM HIGH PRESSURE SENSOR -G65 , checking High Pressure Sensor -G65-. The signal generated by the High Pressure Sensor -G65- is also used to control the engine (the torque that is necessary to drive the compressor depends on the pressure in the refrigerant circuit). The signal is displayed as duty cycle in measuring value block depending on ECM version. The signal that is transferred when the pressure in the refrigerant circuit is approximately 5 to 6 bar, corresponds to an approximate duty cycle of 22% (with compressor not engaged, an ambient temperature of 20 ohmsC and properly filled refrigerant circuit)

Scheme 116

Note. Observe notes in display field 3 The A/C Control Head -E87- calculates via the duty cycle (display field 3) the pressure in the refrigerant circuit. A pressure of 2.6 bar at a temperature of -3 C° is obtained when the refrigerant circuit is properly filled. To avoid malfunction entries at low temperatures, the A/C Control Head -E87- recognizes a malfunction in the refrigerant circuit first at pressure less than 1.8 bar (obtained at -12 C°) However at this temperature the High Pressure Switch -G65- is no longer checked. If the pressure in refrigerant circuit (display field "3" and "4") does not change while the engine is running, even though the regulation valve is being activated with maximum voltage, check belt pulley or drive unit at compressor, the compressor must be driven (in case the overload fuse has activated, the belt pulley runs, however the compressor is not driven). See BELT PULLEY/DRIVE UNIT OF COMPRESSOR, REPLACING .

Scheme 117

Note. If several compressor cut-off conditions exists simultaneously (display field 1), the display will either show them all alternately or it will show only the cut-off condition which is assigned the highest priority by the A/C Control Head -E87-. Display group 1 indicates current compressor cut-off conditions. Display field 2, 3 and 4 only stores compressor cut-off conditions marked with *. They are only stored when more than 20 seconds effective (cut-off condition "12" is already stored after 12 seconds). If the compressor is always switched off and this display group shows no compressor cut-off conditions in display field 2 to 4, check then the display in display groups 026 and 027. If the compressor cut-off condition "3" exists in the A/C control head -E87- (pressure in refrigerant circuit is too low), the E87- automatically switches to "Econ" operating mode and this is stored as a malfunction in the DTC memory.

Interpretation of compressor cut-off condition for display field 1 - 4

Note. Numbers that are not mentioned (e.g. 13) are currently not assigned with a compressor cut-off condition.

Scheme 118

Scheme 119

Scheme 120

Scheme 121

Scheme 122

Scheme 123

Scheme 124

Scheme 125

Scheme 126

Scheme 127

Note. If the feedback value in display field 1 is less than 5 (short circuit) or greater than 250 (open circuit) carry out electrical testing. See AUTOMATIC CLIMATE CONTROL SYSTEM, ELECTRICAL TESTING . The A/C Control Head -E87- is programmed with tolerance ranges between 10 and 70 and between 190 and 245 for feedback values relating to the end stops of the actuator for temperature flap. If the basic setting determines a value greater or smaller than the permissible adaptation value, the malfunction "adaptation limit exceeded" is stored in the DTC memory and in measuring value block display fields 3 and 4 show a substitute value for this positioning motor (currently for the lower stop 30 or 220 for the upper stop). If the display values in display fields 3 or 4 are outside the permissible range. See DIAGNOSTIC TROUBLE CODE (DTC) TABLE . If a malfunction has been detected on the integrated potentiometer on one or more positioning motors, activation for positioning motor temperature flap occurs via the vent temperature sensor measuring value. In case of malfunction A/C Control Module -E87- activates all other positioning motors through a stored emergency program (time activation).

Scheme 128

Note. See DISPLAY GROUP 003 .

Scheme 129

Note. During "defrost mode" the defroster flap is also not completely opened, this helps to direct some air to other vents. 145 to 160 is displayed for the upper specified feedback value. Additional notes, see DISPLAY GROUP 003

Scheme 130

Note. Depending on the position of the positioning motors and through the attached levers on the flaps, the following operating conditions of the climate control (and all positions in between) possible: - Footwell and central flap closed = Defroster mode (air to front windshield) - Footwell open and central flap closed = Air in footwell (feedback value in display field 1 and 2 between 70 and 90). 2 between 110 and 150). - Footwell flap close and central flap open = Air flows out of instrument panel vents

Additional notes, see DISPLAY GROUP 003

Scheme 131

Note. This positioning motor activates the back pressure/fresh air flaps. When vehicle is stationary the back pressure operation position in only obtained during the output Diagnostic Test Mode (DTM).

Depending on the position of the positioning motors and through the attached levers on the flaps, the following operating conditions of the climate control (and all positions in between) are possible

1. Back pressure/fresh air flaps closed and recirculated air flap open = Recirculated air mode
2. Back pressure/fresh air flaps open and recirculated air flap closed = Fresh air mode.
3. Back pressure/fresh air flaps partially closed and recirculated air flap closed = back pressure mode (feedback value in display field 1 and 2 between approx. 110 and 170).

In back pressure air mode the position of the back pressure/fresh air flaps is programmed. As of 80 km/h the flaps will be closed depending on the vehicle speed, fresh air fan speed, the selected and actual measured temperatures as well as the selected operation mode of A/C Control Head -E87- The back pressure/fresh air flaps are not fully closed in back pressure mode (they remain as far open so that the necessary air flow remains).

Additional notes, see DISPLAY GROUP 003

Scheme 132

Note. The Recirculation Flap Motor -V113- only moves the recirculated air flap, the back pressure/fresh air flaps are moved by Air Flow Flap Motor -V71-. Additional notes, see DISPLAY GROUP 003

Display group 009

Measuring values of Left Footwell Vent Temperature Sensor -G261-, Right Footwell Vent Temperature Sensor - G262-, Left Vent Temperature Sensor -G150- and Right Vent Temperature Sensor -G151

DISPLAY GROUP 009 - MEASURING VALUES OF LEFT AND RIGHT FOOTWELL VENT TEMPERATURE SENSOR

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 from instrument cluster

DISPLAY GROUP 010 - MEASURING VALUES FOR EVAPORATOR VENT TEMPERATURE SENSOR

Note. Notes for display field 1: The A/C Control Head -E87- switches the compressor off if the Evaporator Vent Temperature Sensor -G263- measures a temperature less than 2° C for a longer period of time. The measuring value of Evaporator Vent Temperature Sensor -G263- is used to control the evaporator temperature. The evaporator temperature changes by activating the A/C Compressor Regulator Valve -N280-. See DISPLAY GROUP 001 . The temperature of Evaporator Vent Temperature Sensor -G263- is regulated to the following values depending on A/C Control Head -E87- adjustment

1. During normal operation between 2 and 10°C
2. At outside temperature less than 13 °C at least 3 °C below determined outside temperature, however not smaller than 2 °C.
3. At outside temperatures less than 16 °C and rain (windshield wipers switched on) at least 6 °C below the determined outside temperature however not smaller than 2 °C.
4. At pre-selected temperature "Lo" at -E87- to 2 °C
5. In "recirculating mode" at -E87- to a minimum of 5 °C however not smaller than 2 °C.

1. The fixed temperatures on Evaporator Vent Temperature Sensor -G263- are not obtained at higher ambient temperatures (although the compressor works at maximum output).
2. Display group 001 display fields 1 and 2 show the activation of A/C Compressor Regulator Valve -N280- used to regulate the compressor output. See «A/C COMPRESSOR REGULATOR VALVE -N280- AND HIGH PRESSURE SENSOR -G65»(/audi/a4/b6-2000-2006/remont/communication-devices/#on-board-diagnostic-obd__ac-compressor-regulator-valve-n280-and) .

Note. Note for display fields 3 and 4: Check measuring values of Outside Air Temperature Sensor -G17-. See VAS 5051 Vehicle Diagnostic Testing and Information System The radiating heat of the radiator and exhaust system influences the measuring values of -G17- and -G89- on stationary vehicles. For this reason a computing program is integrated in the instrument cluster, eg. if the vehicle is in a traffic jam or city traffic the measured temperature is suppressed and the colder calculated value instead of the measured value is shown in the outside temperature display. The measured lower temperature of both outside temperatures => display field 2 and 4 is the basis for display field 3. The value will be stored up to 4 hours after the ignition is switched off and the current measuring values are not displayed.

Display group 011

Measuring value of Instrument Panel Interior Temperature Sensor -G56-, the measured RPM of Interior Temperature Sensor Fan -V42-, coolant temperature transmitted by instrument cluster and output activation for idle air control increase

Scheme 133

Note. Notes for display field 1: The Instrument Panel Interior Temperature Sensor -G56- is vented by Interior Temperature Sensor Fan -V42-. The actual interior temperature cannot be properly detected and the system operates incorrectly, if the intake frame in A/C Control Head -E87- trim is closed or the Interior Temperature Sensor Fan -V42- does not run properly. The Instrument Panel Interior Temperature Sensor -G56- is part of A/C Control Head -E87- and cannot be replaced separately. The Interior Temperature Sensor Fan -V42- always runs with the ignition switched on

Note. Notes for display field 2: The Instrument Panel Interior Temperature Sensor -G56- is vented by Interior Temperature Sensor Fan -V42-. The actual interior temperature cannot be properly detected and the system operates incorrectly, if the intake frame in A/C Control Head -E87- trim is closed or the Interior Temperature Sensor Fan -V42- does not run properly. A malfunction will be stored in the DTC memory if Interior Temperature Sensor Fan -V42- is not moving freely and the fan speed is less than 1500 RPM At room temperature the fan speed is approximately 3000 RPM The Interior Temperature Sensor Fan -V42- is part of A/C Control Head -E87- and cannot be replaced separately. The Interior Temperature Sensor Fan -V42- always runs with the ignition switched on

DISPLAY GROUP 011 - MEASURING VALUE OF INSTRUMENT PANEL INTERIOR TEMPERATURE SENSOR G56

Note. Notes for display field 3: To avoid sudden compressor cut-off if the engine coolant temperature is too high, the A/C Control Head -E87- regulates (reduces) the compressor performance as soon as the transmitted coolant temperature from the instrument cluster exceeds 115°C (at 118 °C the compressor completely switched off). If the coolant temperature is less than 40 °C the instrument cluster may not transfer the coolant temperature via the CAN-bus comfort system. In this case start engine and wait until coolant temperature is greater than 40 °C. If not OK is displayed with a warm engine, carry out instrument cluster On Board Diagnostic. See VAS 5051 Vehicle Diagnostic Testing and Information System

Note. Note for display field 4: The signal process in the ECM differs between individual engines. Check Idle Air Control (IAC) regulation (idle speed increase) See VAS 5051 Vehicle Diagnostic Testing and Information System For the idle regulator to switch on, there cannot be any A/C compressor cut-off conditions present that would prevent the A/C Compressor Regulator Valve -N280- from switching on (e.g. engine not running or operation mode "Econ" selected). The A/C Control Head -E87- switches the request e.g. with "Lo" or "High" pre-select temperature request. Via this function the engine control module is informed, that climate control system requires a higher engine speed in order to attain the preset adjustment (higher compressor RPM or more power from engine). The A/C Control Head -E87- switches the idle speed increase request on in order to achieve a better heating or cooling performance, e.g. with pre-selected temperature "Hi" or "Lo" (on "Lo" only with compressor engaged).

Display group 012

The current engine speed and vehicle speed transmitted from the instrument cluster, condition and value of compressor torque transmitted to the instrument cluster

Scheme 134

Note. Note for display field 2: If the vehicle has been driven more than 5 km/h with ignition switched on before entering the On Board Diagnostic, when the vehicle is stationary a "1" displays that the speed signal was at least once received.

Scheme 135

Note. Note for display field 3: Display "1" occurs e.g. short time after ignition is switched on or if terminal "15" is not switched on, no signal is received from instrument cluster control module.

Scheme 136

Note. Note for display field 4: The A/C Control Head -E87- utilizes different measuring values to calculate the compressor torque (e.g. ambient temperature, pressure in refrigerant circuit etc.). Depending on these influencing variables, with the compressor switched on a value between 1 - 25 Nm can be calculated. A value of less than 1.0 Nm is displayed if the compressor is switched off.

Display group 013

The activation of the Fresh Air Blower -V2- and the calculated fresh air blower speed, from the instrument cluster transmitted voltage on terminal 58d and 58s

Scheme 137

Note. Notes for display field 1 and 2: The Control module for fresh air blower -J126- is integrated in the Fresh Air Blower -V2- and can currently not be replaced individually. The activation of -V2- is calculated by the A/C control head -E87- based on the measured temperatures and the available adjustments. The fresh air blower speed is transmitted from the Control module for fresh air blower -J126- to the A/C control module -E87-. The fresh air blower speed is lowered, in order to understand the speech recognition and speech input of the telephone better

Scheme 138

1. The speed decrease comes in affect, as soon as "Telephone speech input" information is sent via the CAN-bus comfort system is
2. The time of speed decrease is limited to maximum 2 minutes.
3. The amount of speed lowered depends on the air direction and the fresh air blower speed when the signal "Telephone speech input" is entered. If the amount of air which is directed to the dash panel vents is high, the speed will lowered.
4. In "Basic setting" the fresh air blower speed of 100% air is limited to 15% at the dash panel vents. Maximum fresh air blower speed limited. Via the "Adaptation" function adaptation channel "8" the limitation can be lowered or canceled, see «ADAPTATION OF FRESH AIR BLOWER RPM DECREASE, PERFORMING (ADAPTATION CHANNEL 08)»(/audi/a4/b6-2000-2006/remont/communication-devices/#on-board-diagnostic-obd__adaptation-of-fresh-air-blower-rpm) .

Note. Note for display field 3: With ignition switched on the instrument cluster always supplies voltage to terminal 58d to illuminate the display. During day time light it is possible that always 100% is displayed depending of the brightness falling on the instrument cluster.

Note. Note for display field 4: Voltage is supplied to terminal 58s to illuminate the switches, only with the running lights switched on. During day time light it is possible that always 100% is displayed depending of the lighting intensity (brightness) falling on the instrument cluster.

See VAS 5051 Vehicle Diagnostic Testing and Information System

Display group 014

The activation of Coolant Fan -V7-, the signal from Sensor for air quality -G238- and the request for fresh or recirculated air mode

Scheme 139

Note. Notes for display field 1: The A/C Control Head -E87- sends the request to switch on the coolant fan, as long as no compressor cut-off condition exists (A/C Compressor Regulator Valve -N280-) which disables the compressor to be switched on (e.g. engine not running or operation mode "Econ" selected). The Coolant FC (Fan Control) Control Module -J293- gradually regulates the coolant fan. The activation of Coolant FC (Fan Control) Control Module -J293- occurs from the Engine Control Module (ECM). In order to activate the coolant fan, the A/C Control Head -E87- activates the Engine Control Module (ECM) via the CAN-bus comfort system. See MEASURING VALUE BLOCKS 001 TO 010 . The ECM activates the Coolant FC (Fan Control) Control Module -J293- (and therefore the fans) but only with engine running. The A/C control head -E87- sends the request to the Engine Control Module (ECM) to switch on the coolant fans. Vehicles with gas engines request 100% fan speed currently at approx.: 26 bar pressure in the refrigerant circuit.

Scheme 140

Scheme 141

Note. Notes for display field 3: Oxidizable gases are e.g. Carbon monoxide, Benzol, Hexan etc. they reacted with oxygen in the air and can be found e.g. in the exhaust of an gas engine) Reducible gases are e.g. sulphur dioxide, hydrogen sulfide etc., they react with other matters and supply oxygen, they are common is Diesel engine exhaust.

Scheme 142

Scheme 143

Note. Note for display field 4: Instead of "00" "0" can be displayed as well, if no request for air recirculation is present. Although no request for air quality is requested by the sensor for air quality, "11", "12" or "13" can be displayed, observe display field 3 for this display. With the compressor switched off the "Automatic air recirculation" function is limited to 15 seconds, this avoids the windows from fogging up. If Sensor for air quality -G238- has a malfunction, the "Automatic air recirculation mode" is not possible. No air recirculation is possible during defrost mode, this helps to defog windows more quickly. The purpose of the air quality sensor is to keep out temporary high concentrations of pollutants (load peaks) from outside air, coming into the passenger compartment. After the A/C Control Head -E87- receives a request from Sensor for air quality -G238-; the system switches from "fresh air" mode to "recirculated air" mode. If outside air pollution load remains high for longer period of time, the sensor starts to adapt it self 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. The climate control system may also operate a longer period of time in air recirculation mode, if more load peaks occur after another.

Scheme 144

Scheme 145

Note. Note for display field 4: The "Partial air recirculation" function has been introduced for more comfort. The running sound of the fresh air fan changes when switching operating modes of the climate control system, by the changing the procedure (flaps are activated one after the other, and no longer simultaneously) the change is therefore softer. The climate control system may operate for longer period of time in "Partial air recirculation mode" (e.g. to attain good cooling temperature at high outside temperatures, without operating constantly in air recirculation mode). Instead of "00" "0" can be displayed as well, if no request for air recirculation is present. No air recirculation is possible during defrost mode, this helps to defog windows more quickly.

Display group 015

The activation of Heated rear window -Z1-, activation of Heated front window -Z2- and convertible top position on convertible

Scheme 146

Note. Notes for display field 1: Activation of heated rear window checking, see COMPONENTS ACTIVATED BY A/C CONTROL HEAD -E87-, ELECTRICAL TESTING The heated rear window stays switched on with outside temperatures up to 0 °C until ignition is switched off (heated rear window can be manually switched off anytime). If the temperature increases above 0 °C during a driving cycle, the heated rear window will be switched off after the specified operating time -E87-) of approx.: 12 minutes elapsed. With outside temperatures greater than 0 °C the heated rear window is switched off automatically by the -E87- after the programmed operating time (approximately 12 minutes) elapsed.

Scheme 147

Note. Notes for display field 2: If vehicle is not equipped with heated front window and -J505-,"not installed" or "0" or "00" is shown. As long as the voltage on Heated Windshield Control Module -J505- is greater than 12.7 volts and the control module is not too hot, the Heated Windshield Control Module -J505- switches approximately battery voltage to the output for A/C Control Head -E87- In the event that the heated front window has to be switched on, the A/C Control Head -E87- activates a transistor, which cut's the voltage on connector -C- terminal 8 in half. The Heated Windshield Control Module -J505- switches the heated front window on If, during the heating operation of front window the voltage (vehicle voltage on -J505-) drops below 12.7 volts or -J505- is getting too hot, a switch opens in -J505- and the voltage at the output to A/C Control Head -E87- will be less than 5 volt, the -J505- switches the heated front window off simultaneously. Function of windshield defroster, see WINDSHIELD DEFROSTER, FUNCTION

Scheme 148

Note. Note for display field 4: Only observe display on convertible. The A/C control head changes the control characteristics, if an open top is recognized (a closed passenger compartment is no longer available).

Display group 016

Measuring values for sunlight photo sensor and the calculated sunlight

DISPLAY GROUP 016 MEASURING VALUES FOR SUNLIGHT PHOTO SENSOR AND THE CALCULATED SUNLIGHT

Note. The display value of Sunlight Photo Sensor -G107- can be changed by shining with a suitable light onto the sensor. If, independent of the illumination of the Sunlight Photo Sensor -G107 is always approx.: 900 Watt pro m 2 (corresponds to approx. 4.5 volt) sun rays are displayed, check wiring to Sunlight Photo Sensor -G107- according to wiring diagram for mix up. The displayed sun ray value depends on the time of the year and day time as well as the vehicle location (the measuring value in central Europe at max: sun rays is approximately 300 - 500 Watt per m 2 ).

Display group 017

The transmitted or measured voltage on terminal 15, 75 and 30

Scheme 149

Scheme 150

Display group 018

Time period "ignition off" transmitted from instrument cluster and transmitted ignition key assignment, Signal for windshield wiper operation transmitted by Steering Column Electronic Systems Control Module -J527- and the operating condition of Fresh Air Blower -V2- transmitted by Control module for fresh air blower -J126

Scheme 151

Note. Notes for display field 1: If the signal "ignition off" period is not detected by the A/C Control Head -E87- when the ignition is switched on, the A/C Control Head -E87- assumes that the vehicle has been left standing for more than 4 hours, and the engine temperature is assumed to be identical to the ambient temperature. Possible causes: Although the engine is warm, in heating mode the fresh air fan may start with a delay. The outside air temperature display -G106- in the instrument cluster may display incorrect ambient temperature values. After 4 hours stand time the A/C Control Head -E87- assumes during temperature calculation, that all parts of the vehicle have ambient temperatures. The display in this field is limited to a stored value in the A/C control head -E87- (e.g. 04:46h) or the actual time will be displayed.

Scheme 152

Note. Notes for display field 2: The instrument cluster can only transmit the coding of the ignition key on vehicles equipped with immobilizer. See INSTRUMENT CLUSTER (except Cabriolet), or INSTRUMENT CLUSTER for the Cabriolet. When ignition is switched on, A/C control head -E87- begins with the setting that was valid when the ignition was last switched off with this key (temperature, air distribution, fresh air blower RPM). If the ignition is switched on (e.g. via emergency function) with a key that was not enabled for this vehicle, the A/C Control Head -E87- switches automatically to "Off" mode after the ignition is switched on, and with the ignition switched on the -E87- can only be switched to "Def" mode (other adjustments are not possible). The malfunction "Anti-Theft Engine Disable Control Module -J334-" is stored simultaneously in the A/C control head -E87-. This function has been adapted to improve the anti-theft system.

Scheme 153

Note. Notes for display field 3: Depending on the windshield wiper switch position several operating conditions can be displayed simultaneously (e.g. 01001 for wipe/wash mode and interval mode). The operating condition information is used to control the evaporator vent temperature and for vehicles with air quality sensor.

Scheme 154

Scheme 155

Note. Note for display field 4: If fresh air blower activation is OK and Control module for fresh air blower -J126- does not recognizes a malfunction, the current fresh air blower RPM is then transmitted as square-wave signal to the A/C control head -E87-. The duty cycle on this square wave is approx. 50% and the frequency 1/20 of fresh air blower RPM (for example: If the fresh air blower fan has a speed of 3000 RPM, the frequency of the square wave signal is 150 Hertz or impulses per seconds). If the Control module for fresh air blower -J126- detects a malfunction, the -J126- sends a square wave signal with a frequency of 10 Hertz (impulses per second). The A/C control head -E87- recognizes the detected malfunction via the duty cycle.

Display group 019

Transmitted coding from Central control module for comfort system -J393- and Control module with indicator unit in instrument cluster -J285

Scheme 156

Table for codings transmitted by instrument cluster (and adapted during "Basic Setting" function) "1"

Scheme 157

Note. Notes for display field 1: Some equipment and functions pertain to certain models only or are offered only in certain markets. The coding "Germany", "Europe", "Canada" or "Great Britain" are used for other vehicle systems, these codes currently have no variations in the climate control system. With this coding, the "recirculated air" mode function is canceled when the ignition is switched off and the temperature display in the instrument cluster and A/C control head -E87- is switched to °C (Celsius). The temperature display on the A/C control head -E87- can be switched. See A/C CONTROL HEAD -E87-, REMOVING AND INSTALLING . If the coding "Japan" is transmitted from the instrument cluster, the "recirculated air mode" function is stored when switching the ignition off, and when switching the ignition on with this key, the A/C control head -E87- switches to recirculated air mode (this coding is not permissible for USA vehicles). If coding "USA" is transmitted from the instrument cluster, the climate control operates somewhat "cooler" and the temperature display is switched to °F (Fahrenheit). The temperature display on the A/C control head -E87- can be switched. See A/C CONTROL HEAD -E87-, REMOVING AND INSTALLING . If coding "Australia" or "Saudi Arabia" is transmitted from instrument cluster, the climate control operates somewhat "cooler". If the coding for right hand steering vehicle was transmitted, the A/C control head -E87- changes the activation for the positioning motors (different wiring connection of connectors on positioning motors), the A/C control head -E87- no longer recognizes the missing Air Flow Flap Motor -V71- as a malfunction and the seat recognition for heated driver and passenger seats is reversed (mixed up). The calculated heating of the coolant after cold start by the A/C control head -E87- varies between different engine variants. If coding of A/C Control Head -E87- is to be changed e.g. to a different country version (e.g. to rest of world control characteristics, regulation in summer somewhat warmer than USA control characteristics) but the coding in Control module with indicator unit in instrument panel insert -J285- is not to be changed, proceed as follows: Change the coding in Control module with indicator unit in instrument panel insert -J285- to the desired country coding. Perform Basic Setting of A/C Control Head -E87-. Change the coding of Control module with indicator unit in instrument panel insert -J285- back to the original country coding.

Table for codings transmitted by Control module with indicator unit in instrument panel insert -J285- (and adapted during "Basic Setting" function) "2"

Scheme 158

Note. Some equipment and functions pertain to certain models only or are offered only in certain markets. If the coding "vehicle with auxiliary heating" is transmitted by Control module with indicator unit in instrument cluster -J285-, the A/C control head -E87- awaits information from Control module for auxiliary heater -J364-, if this information is not received this will be stored as malfunction in the -E87-. The heating of the coolant after cold start calculated by the A/C control head -E87- varies between different engine variants.

Display group 020

Position of thumb wheel for heated seat driver's side, actual and specified temperature of Driver's Heated Seat Temperature Sensor -G59- and activation of Driver's Heated Seat Temperature Sensor -G59

Note. This display group should only be observed on vehicles with heated seats.

Scheme 159

Note. Notes for display field 1: The position of the thumbwheel is determined via a potentiometer by the A/C control head -E87- (changeable resistance), via tolerances in this potentiometer no permanent value for the respective position can determined.

DISPLAY GROUP 020 - POSITION OF THUMB WHEEL FOR HEATED SEAT DRIVER'S SIDE

Note. Notes for display field 2: If the temperature sensor wiring or temperature sensor itself has an open circuit, a substitute value of -30 °C is displayed as actual temperature (e.g.-49 °C) and heated seats are not switched on. The seat heating elements in seat (heating element for seat surface, backrest and seat bolsters) are connected to each other in different ways. If there is e.g. an open circuit in heating element for seat surface, seat bolster can still be heated anyway depending on the construction of the seat heater, since the seat surface (and the temperature sensor in seat) remains cold however, seat bolsters are heated without regulation. If generator generates too little current, heating performance of seat heater is reduced by A/C Control Head -E87- or seat heater is switched off completely. If voltage at A/C Control Head -E87- is lower than approx. 12.3 V (see DISPLAY GROUP 017 ) output to seat heating elements is no longer activated steadily but only pulsed (although specified temperature has not yet been reached), at a voltage lower than approx. 10.6 V seat heater is switched off completely.

Scheme 160

Note. Notes for display field 3: -41 to -61 (-99) °C is displayed if the thumbwheel is in position "0", this ensures, that in this position at extreme temperatures the seat heating is not switched on. Do not observe display in display field 3, if the measured actual temperature (display field 2) is higher than the adjusted specified temperature (display field 3) and the displayed specified-temperature is below the specified temperature value for the thumbwheel position. The position of the thumbwheel is determined via a potentiometer by the A/C control head -E87- (changeable resistance), via tolerances in this potentiometer no permanent value for the respective position can be determined. Therefore, the displayed specified temperature can deviate from the specified temperature in the display field. Depending on the version of A/C Control Head -E87-, the displayed specified temperature (of seat surface) in display field for this position of the thumbwheel changes: Already when leaving position "0" of -41 to -61 (-99) °C to indicated specified temperature. or The display only then changes from -41 to -61 (-99) °C to indicated specified temperature (of seat surface) if specified temperature is greater than the measured actual temperature in seat surface.

Display group 021

Position of thumbwheel for heated seat passenger's side, actual and specified temperature of Passenger's Heated Seat Temperature Sensor -G60- and activation of Passenger's Heated Seat Temperature Sensor -G60

Note. This display group should only be observed on vehicles with heated seats.

Scheme 161

Note. Notes for display field 1: The position of the thumbwheel is determined via a potentiometer by the A/C control head -E87- (changeable resistance), via tolerances in this potentiometer no permanent value for the respective position can determined.

DISPLAY GROUP 021 - POSITION OF THUMBWHEEL FOR HEATED SEAT PASSENGER'S SIDE

Note. Notes for display field 2: If the temperature sensor wiring or temperature sensor itself has an open circuit, a substitute value of -30 °C is displayed as actual temperature (e.g.-49 °C) and heated seats are not switched on. The seat heating elements in seat (heating element for seat surface, backrest and seat bolsters) are connected to each other in different ways. If there is e.g. an open circuit in heating element for seat surface, seat bolster can still be heated anyway depending on the construction of the seat heater, since the seat surface (and the temperature sensor in seat) remains cold however, seat bolsters are heated without regulation. If generator generates too little current, heating performance of seat heater is reduced by A/C Control Head -E87- or seat heater is switched off completely. If voltage at A/C Control Head -E87- is lower than approx. 12.3 V (see DISPLAY GROUP 017 ) output to seat heating elements is no longer activated steadily but only pulsed (although specified temperature has not yet been reached), at a voltage lower than approx. 10.6 V seat heater is switched off completely.

Scheme 162

Note. Notes for display field 3: -41 to -61 (-99) °C is displayed if the thumbwheel is in position "0", this ensures, that in this position at extreme temperatures the seat heating is not switched on. Do not observe display in display field 3, if the measured actual temperature (display field 2) is higher than the adjusted specified temperature (display field 3) and the displayed specified-temperature is below the specified temperature value for the thumbwheel position. The position of the thumbwheel is determined via a potentiometer by the A/C control head -E87- (changeable resistance), via tolerances in this potentiometer no permanent value for the respective position can determined. Therefore, the displayed specified temperature can deviate from the specified temperature in the display field. Depending on the version of A/C Control Head -E87-, the displayed specified temperature (of seat surface) in display field for this position of the thumbwheel changes: Already when leaving position "0" of -41 to -61 (-99) °C to indicated specified temperature. or The display only then changes from -41 to -61 (-99) °C to indicated specified temperature (of seat surface) if specified temperature is greater than the measured actual temperature in seat surface.

Display group 022

Input signal from auxiliary heating, input signal for auxiliary heating or stationary ventilation from instrument cluster, input signal for fresh air blower from auxiliary heating and remaining switch-on period of auxiliary heating/stationary ventilation calculated by the A/C control head -E87

DISPLAY GROUP 022 - INPUT SIGNAL FROM AUXILIARY HEATING, INPUT SIGNAL FOR AUXILIARY HEATING OR STATIONARY VENTILATION FROM INSTRUMENT CLUSTER

Note. Display always "0" (no signal from auxiliary heating). If the A/C control head -E87- remains operational although the ignition is switched off and the display "one" appears in display field "1", determine harness connector D, terminal 10 for short circuit to B+ and repair.

Display groups 026 and 027

The ambient conditions under which the pressure in the refrigerant circuit was last not OK

Note. The display fields of display groups "026" and "027" will display "erased", if no malfunction was recognized since the DTC memory was erased last.

Scheme 163

Note. Notes for display field 1: The "0819" is the DTC number for malfunction location "High Pressure Sensor -G65-"

Scheme 164

DISPLAY GROUPS 027 - AMBIENT CONDITIONS UNDER WHICH PRESSURE IN REFRIGERANT CIRCUIT WAS LAST NOT OK

Display group 081

Vehicle Identification Number of this vehicle transmitted by the instrument cluster

Scheme 165

DISPLAY GROUP 081 - VEHICLE IDENTIFICATION NUMBER OF VEHICLE TRANSMITTED BY INSTRUMENT CLUSTER

Display group 125

Information on the CAN-bus comfort system and operating condition of the Bus-system

Scheme 166

Note. Notes to display field 1: With A/C Control Head -E87- up to index "G" (up to software version "XX14") Combi "0" is displayed in display field 1 with certain optional equipment also if message is correctly received. The display "1" only appears for this version, as long as e.g. "speech recognition telephone operation" function is transferred from control module in instrument cluster. With A/C Control Head -E87- up to index "G" (up to software version "XX14"), if Combi "0" is displayed in display field 1 and double wire operation in display group "126" display field "4", check display in instrument cluster. If "Klima 1" is displayed in measuring value block (at this time 131) here, CAN-bus comfort system is OK. Disregard the malfunction "control module in instrument cluster no communication /SP".

See VAS 5051 Vehicle Diagnostic Testing and Information System

Scheme 167

Display group 126

Information from Control module for auxiliary heater -J364- and Convertible Top Control Module -J256- on the CAN-bus comfort system and operating condition of CAN-bus comfort system

Scheme 168

Note. Notes for display field 2: For the Audi Cabriolet, different adjustments for closed and open convertible top are stored in the A/C Control Head -E87-. When opening and closing the convertible top, the A/C Control Head -E87- independently changes the adjustment to the value which was last adjusted during closed or open convertible top. As of model year 2003, A/C Control Head -E87- with part number as of index "H" (with hard-/software version as of "XX16") will be implemented as a running change. These A/C Control Heads -E87- differ from the software version as of "XX15" in the following points: The temperature regulation for the passenger compartment in the Audi Cabriolet and opened convertible top was changed and therefore was adjusted somewhat lower. The Temperature adjustment range was expanded, the lowest temperature of 16 °C can now be selected (instead of previous 18 °C). => Parts catalog

Note. Notes to display field 3: A component that is contained via the "speech recognition telephone operation" function is displayed in this display field, which received the message via CAN-Bus comfort system from the instrument cluster. The information "speech recognition telephone operation" is only transmitted by vehicles with hands-free equipment installed at production time. Depending on the version of the vehicle, the information is then only sent if the button for speech input was operated at least once since switching on ignition or telephone was put into operation. Depending on the version of A/C Control Head -E87-, information "speech 1" is only displayed as long as the information is actually received via CAN-Bus comfort system.

Scheme 169

Note. Note for display field 4: Compared to the CAN-bus system, the CAN-bus comfort system can also operate in a single wire mode. The system then operates in emergency mode. If no information is received on the CAN-bus comfort system, the regulator valve for the compressor is not activated by the A/C control head -E87- (compressor is not engaged).

Display groups currently not to be used by dealerships

Note. Depending on the A/C control head -E87- version, these measuring value blocks may not indicate any display or the display field is black.

Scheme 170

Scheme 171

Scheme 172

Overview of designated adaptation channels

Note. Adaptation channels 01, 02, 06 and 07 are in effect only for vehicles in which the auxiliary heater is installed as optional equipment. Since the auxiliary heater is not available for the USA, these adaptation channels are to be disregarded for USA. If input "0" is entered in adaptation channel 03, it is to be noted in vehicle records that the activation of A/C Compressor Regulator Valve -N280- can no longer be shut off via the "A/C compressor cut-in" function from Engine Control Module (ECM). See VAS 5051 Vehicle Diagnostic Testing and Information System

Adaptation (function 10) in channel 03, performing

1. Check DTC memory of A/C Control Head -E87- and eliminate all displayed malfunctions. See «DIAGNOSTIC TROUBLE CODE (DTC) MEMORY, CHECKING (FUNCTION 02)»(/audi/a4/b6-2000-2006/remont/communication-devices/#on-board-diagnostic-obd__diagnostic-trouble-code-dtc-memory-checking) .
2. Check coding of A/C Control Head -E87- for vehicle equipment options and correct if necessary. See «A/C CONTROL HEAD -E87-, CODING (FUNCTION 07)»(/audi/a4/b6-2000-2006/remont/communication-devices/#on-board-diagnostic-obd__ac-control-head-e87-coding-function) .

Indicated on display of VAS 5051

Scheme 173

1. Select "Adaptation" function 10.

Indicated on display of VAS 5051

Scheme 174

1. Display field -1- indicates the request to input channel number.
2. Display field -2- shows input keyboard.

Scheme 175

1. Input the desired channel number in display field -2- via the keyboard (see «A/C CONTROL HEAD -E87-, ADAPTATION (FUNCTION 10)»(/audi/a4/b6-2000-2006/remont/communication-devices/#on-board-diagnostic-obd) ) overview of designated adaptation channels) and confirm by pressing the -Q- button. (Scheme 188) NOTE: If "Function unknown or cannot be performed at the moment" is displayed in display field -1-, the following may be the cause
2. The control module adaptation has not been carried out according to specification and was not completed.
3. The CAN-bus comfort system has a malfunction.

Indicated on display of VAS 5051

Scheme 176

1. Display field -1- indicates "Channel X read and test".
2. In area -2-, the currently adjusted value for this function is displayed.
3. In area -3-, a scroll bar appears with an identification number for the currently valid adjustment.

Scheme 177

1. The adjustment can be changed within the determined limits via the scroll bar. NOTE: If an identification number is entered via scroll bar that is outside the determined limits, the identification number is shown but will not be implemented. If an identification number which is too large or too small is entered via scroll bar, the display changes back automatically. In area -2-, the newly adjusted value for this adaptation channel is displayed. The input can also be carried out using the keyboard
2. Touch button -4- (input via keyboard)

Indicated on display of VAS 5051

Scheme 178

1. In display field -1- occurs the display "input adaptation value: 0....XXXXX".
2. Display field -2- shows input keyboard.

Scheme 179

1. Input in the display field the desired value for this adaptation channel via the keyboard (see «OVERVIEW OF DESIGNATED ADAPTATION CHANNELS»(/audi/a4/b6-2000-2006/remont/communication-devices/#on-board-diagnostic-obd__overview-of-designated-adaptation-channels) ) overview of designated adaptation channels) for the new adaptation of the A/C control head -E87-. NOTE: If an identification number is entered via keyboard that is outside the determined limits, the identification number is shown but will not be implemented. If an identification number which is too large or too small is entered via keyboard, the display changes back automatically. The entered identification number is displayed in area -2-. (Scheme 192)
2. Press -Q- button to confirm input.

Indicated on display of VAS 5051

Scheme 180

1. In area -2-, the new value for this adaptation channel is displayed.
2. The entered identification number appears in area -3- above the scroll bar.

1. Save input by touching button -5-.

Indicated on display of VAS 5051

Scheme 181

1. Display field -1- indicates "Channel X save".
2. In area -2-, the new value for this adaptation channel is displayed.
3. In area -3- appears the original and new identification number for this adaptation channel.

1. Accept and save input by touching button -4-. Display field -1- indicates "Channel X save, value 0 - XXXX saved". NOTE: If an identification number that is outside the determined limits was entered, the identification number is shown but will not be implemented. If an identification number which is too large or too small was entered, the display changes back automatically. By clicking the --> button you will return to the selection menu.
2. End On Board Diagnostic (OBD) (see «END OUTPUT (FUNCTION 06)»(/audi/a4/b6-2000-2006/remont/communication-devices/#on-board-diagnostic-obd) ) and switch ignition off.
3. Check function of the new, entered adaptation.

Adaptation of fresh air blower RPM decrease, performing (adaptation channel 08)

Note. The fresh air blower speed is lowered so that the speech recognition and speech input of the telephone can be understood better: The speed decrease comes in affect, as soon as "Telephone speech input" information is sent via the CAN-bus comfort system. The time of speed decrease is limited to a maximum of 2 minutes. The amount of fresh air blower speed that will be decreased, depends on the direction of air and of the fresh air blower RPM when the "Telephone speech input" signal occurs. As more air is directed to the instrument pane vents, the fresh air blower speed is decreased. The fresh air blower-RPM decrease comes in affect when approximately 40% of air is directed to the instrument panel vents, the maximum decrease occurs at 100% of air at the instrument panel vents. In "Basic setting" the fresh air blower speed of 100% air to the instrument panel vents is limited to 15% of maximum fresh air blower RPM. This limit can be lowered or increased via the "Adaptation" function in adaptation channel "8". To avoid repeat visits by the customer, after the adaptation has been changed it is reasonable to talk to the customer about the functioning of the speech input function and how it relates to the fresh air blower speed decrease (i.e. 100% air to instrument panel vents) and test if necessary.

Carry out adaptation

1. Check DTC memory of A/C control head -E87- (see «DIAGNOSTIC TROUBLE CODE (DTC) MEMORY, CHECKING (FUNCTION 02)»(/audi/a4/b6-2000-2006/remont/communication-devices/#on-board-diagnostic-obd__diagnostic-trouble-code-dtc-memory-checking) ) and eliminate all displayed malfunctions.
2. Check coding of A/C control head -E87- for vehicle equipment options and correct if necessary. See «A/C CONTROL HEAD -E87-, CODING (FUNCTION 07)»(/audi/a4/b6-2000-2006/remont/communication-devices/#on-board-diagnostic-obd__ac-control-head-e87-coding-function) .

Indicated on display of VAS 5051

Scheme 182

1. Select "Adaptation" function 10.

Indicated on display of VAS 5051

Scheme 183

1. Display field -1- indicates the request to input channel number.
2. Display field -2- shows input keyboard.

Scheme 184

1. Input via the keyboard -8- for channel "8" in display field -2- and accept by pressing the -Q- button. (Scheme 197) NOTE: If "Function is unknown or cannot be carried out at the moment" is displayed in display field -1-, the following may be the cause
2. The control module adaptation has not been carried out according to specification and was not completed.
3. The CAN-bus comfort system has a malfunction.

Indicated on display of VAS 5051

Scheme 185

1. Display field -1- indicates "Channel 8 read and test".
2. In area -2- appears e.g. "15%".
3. In area -3- appears a scroll bar with a characteristic number for the currently valid maximum fresh air blower speed (e.g. "3840" for "15%").

1. Using the scroll bar you can change the fresh air blower speed during telephone operation between 15% - 88%. NOTE: If a characteristic number that corresponds to a maximum fresh air blower speed of smaller than 15% or greater than 88% has been entered via the scroll bar, the characteristic number will be displayed but it will not be implemented. If the scroll bar is moved above a characteristic number greater than approx. "32600", the display jumps automatically back to 15%. In area -2- appears the new adjusted value for maximum fresh air blower speed during telephone operation Basic setting at manufacturer: 15% (current characteristic number "3840") Adjustable maximum fresh air blower speed during speech recognition: 15% - 88% (current characteristic number "3840" - "22528") The input can also be carried out using the keyboard
2. Touch button -4- (input via keyboard)

Indicated on display of VAS 5051

Scheme 186

1. In display field -1- appears the display "input adaptation value: 0....XXXXX".
2. Display field -2- shows input keyboard.

Scheme 187

1. Input via the keyboard in the display field the value for the desired maximum fresh air blower speed in function "Speech input-telephone" for the new adaptation of the A/C control head -E87-. Basic setting at manufacturer: 15% (current characteristic number "3840") Adjustable maximum fresh air blower speed during telephone operation: 15% - 88% (current characteristic number "3840" - "22528") NOTE: At 88% adjustment the fresh air blower speed will not be lowered anymore. With this adjustment the speech recognition and the understandability of the speech input of the phone at maximum fresh air blower speed and the air direction to the dash panel vents may have interferences. If a characteristic number that corresponds to a maximum fresh air blower speed of smaller than 15% or greater than 88% has been entered via the keyboard, the characteristic number will be displayed but it will not be implemented. If the characteristic number greater than approx. "32600" has been entered with keyboard, the display jumps automatically back to 15%. The fresh air blower-RPM decrease comes in affect when approximately 40% of air is directed to the instrument panel vents, the maximum decrease occurs at 100% of air at the instrument panel vents. The entered characteristic number is displayed in area -2-.
2. Press -Q- button to confirm input.

Indicated on display of VAS 5051

Scheme 188

1. In area -2- appears the newly adjusted value for the maximum fresh air blower speed during telephone operation.
2. The entered characteristic number appears in area -3- above the scroll bar.

1. Save input by touching button -5-.

Indicated on display of VAS 5051

Scheme 189

1. Display field -1- indicates "Channel 8 save".
2. In area -2- appears the newly adjusted value for the maximum fresh air blower speed during telephone operation.
3. In area -3- appears the original and new adjusted value for maximum fresh air blower speed during telephone operation

1. Accept and save input by touching button -5-. Display field -1- indicates "Channel 8 save, value 0 - XXXX saved". NOTE: If a characteristic number has been entered that corresponds to a maximum fresh air blower speed of smaller than 15% or greater than 88%, the characteristic number will be displayed but will not be implemented. If a characteristic number of approx. "32600" is entered, the characteristic number is not considered by A/C control head -E87- and 15% will be saved. By clicking the --> button you will return to the selection menu. Check speech recognition with the newly entered decreased fresh air blower speed.
2. End On Board Diagnostic (OBD) (see «END OUTPUT (FUNCTION 06)»(/audi/a4/b6-2000-2006/remont/communication-devices/#on-board-diagnostic-obd) ) and switch ignition off. Check speech input and speech recognition of telephone as follows
3. Start engine.
4. Select on A/C control head -E87- the function "Maximum fresh air blower speed" and "Air distribution to dash panel vents" or "Defrost" function.
5. Open all dash panel vents
6. Check function of speech input and speech recognition of the telephone with this adjustment.

Adaptation of Vehicle Identification Number (VIN), performing (adaptation channel 81)

Note. The "adaptation" function has to be carried out on A/C control heads -E87- that display the malfunction "control module incorrect VIN". A new replacement A/C control head -E87- is supplied without VIN. The VIN transferred via the CAN-bus comfort system is entered and saved in the A/C control head -E87- when the ignition is first switched on after the installation. If an A/C control head -E87- is to be installed into another vehicle, the transmitted and saved VIN no longer matches, the -E87- recognizes this and stores the malfunction "Control" module incorrect VIN). The VIN that is saved in the A/C control head -E87- is erased by entering the PIN-number during the adaptation function. The adaptation of the A/C control head -E87- can only be carried out by entering the designated PIN-number.

1. Battery completely charged.
2. Check coding of Control module with indicator unit in instrument cluster -J285-, the coding corresponds to the vehicle model and vehicle equipment See VAS 5051 Vehicle Diagnostic Testing and Information System
3. Check Vehicle Identification Number (VIN). The VIN corresponding to the vehicle must be saved in the Control module with indicator unit in instrument cluster -J285-. See VAS 5051 Vehicle Diagnostic Testing and Information System

1. Check DTC memory of A/C control head -E87- (see «DIAGNOSTIC TROUBLE CODE (DTC) MEMORY, CHECKING (FUNCTION 02)»(/audi/a4/b6-2000-2006/remont/communication-devices/#on-board-diagnostic-obd__diagnostic-trouble-code-dtc-memory-checking) ) and if necessary eliminate all possible displayed malfunctions (the malfunction "Control module incorrect VIN" cannot be erased now).
2. Check coding of A/C control head -E87- for vehicle equipment options and correct if necessary. See «A/C CONTROL HEAD -E87-, CODING (FUNCTION 07)»(/audi/a4/b6-2000-2006/remont/communication-devices/#on-board-diagnostic-obd__ac-control-head-e87-coding-function) .

Indicated on display of VAS 5051

Scheme 190

1. Select "Adaptation" function 10.

Indicated on display of VAS 5051

Scheme 191

1. Display field -1- indicates the request to input channel number.
2. Display field -2- shows input keyboard.

Scheme 192

1. Input via keyboard -8- and -1- for channel "81" in display field -2- and accept by pressing the -Q- button. NOTE: If "Function unknown or cannot be carried out at the moment" is displayed in display field -1-, the following may be the cause: The control module adaptation has not been carried out according to specification and was not completed. The CAN-bus comfort system has a malfunction. If the display "blocked" is shown in display field -1- and the blocked time (e.g. "10" for 10 minutes) is currently not available for the adaptation function, because the adaptation has been carried out several times incorrectly. (Scheme 206)
2. Wait until blocked time is expired.

Indicated on display of VAS 5051

Scheme 193

1. Display field -1- indicates "Read channel 81 and test".
2. In area -2- appears "PIN?".
3. A scroll bar appears in area -3- (not used for this application).

1. Touch button -4- (input via keyboard)

Indicated on display of VAS 5051

Scheme 194

1. In display field -1- appears the display "input adaptation value: 0....XXXXX".
2. Display field -2- shows input keyboard.

Scheme 195

1. Input the PIN-number for the new-adaptation of A/C control head -E87- via the keyboard in display field -2-. PIN-number: 26467 The entered PIN number is displayed in area -2-.
2. Press -Q- button to confirm input.

Indicated on display of VAS 5051

Scheme 196

1. The entered PIN number appears in area -3- above the scroll bar.

1. Save input by touching button -5-.

Indicated on display of VAS 5051

Scheme 197

1. Display field -1- indicates "Save channel 81".
2. The original PIN number or "0" and the new PIN-number appears in area -3-.

1. Accept and save input by touching button -5-. Display field -1- indicates "Save channel 81, value 1 saved". NOTE: By clicking the --> button you will return to the selection menu. The VIN that is saved in the A/C control head -E87- is erased by entering the PIN number. The A/C control head -E87- is now ready to the accept via the CAN-bus comfort system the transmitted VIN from the instrument cluster.
2. End On Board Diagnostic (OBD) (see «END OUTPUT (FUNCTION 06)»(/audi/a4/b6-2000-2006/remont/communication-devices/#on-board-diagnostic-obd) ) and switch ignition off.
3. Start engine.
4. Check DTC memory of A/C control head -E87- (see «DIAGNOSTIC TROUBLE CODE (DTC) MEMORY, CHECKING (FUNCTION 02)»(/audi/a4/b6-2000-2006/remont/communication-devices/#on-board-diagnostic-obd__diagnostic-trouble-code-dtc-memory-checking) ) and erase displayed malfunctions (see «DIAGNOSTIC TROUBLE CODE (DTC) MEMORY, ERASING (FUNCTION 05)»(/audi/a4/b6-2000-2006/remont/communication-devices/#on-board-diagnostic-obd__diagnostic-trouble-code-dtc-memory-erasing) ). The malfunction "Control module incorrect VIN" is no longer displayed, or the malfunction can now be erased (if adaptation was carried out correctly).
5. Now check the VIN that was saved in the A/C control module -E87-. See «DISPLAY GROUP 081»(/audi/a4/b6-2000-2006/remont/communication-devices/#on-board-diagnostic-obd__display-group-081) (function "Read Measuring Value Block", display group 081).

Bus

The term bus refers to a system that transports and distributes data.

Audi A4 employs different Bus-systems. These systems operate on different levels. The control module with indicator unit in instrument cluster builds the interface (Gateway) between the different bus-systems.

CAN

The Controller Area Network (CAN) is a bus system that operated using two wires. They are called bus wires. Data is transferred to the connected control modules serially (one after the other) across the bus wires.

These control modules communicate with each other via the CAN-bus, this means they exchange data via the bus-system.

See Self-Study Program number 186 (course number 971903)

1. The CAN-bus comfort system The CAN-bus operates at a speed of 100 K bits/s (100,000 bits per second). Operates even if one wire is faulty, but only in emergency mode (e.g. open circuit). E.g. the following control modules are connected. Control module with indicator unit in instrument cluster - J285- (interface to CAN-bus system) A/C Control Head -E87- Steering Column Electronic Systems Control Module -J527- Additional control modules connected to the CAN-bus comfort system. See appropriate System Wiring Diagrams article
2. CAN-bus system The CAN-bus operates at a speed of 500 K bits/s (500,000 bits per second). Operates only if data can be transferred on both wires (safety mode) E.g. the following control modules are connected. Control module with indicator unit in instrument cluster -J285- (interface to CAN-bus comfort system) The Engine Control Module (ECM) Additional control modules connected to the CAN-bus system. See appropriate System Wiring Diagrams article NOTE: The term "CAN-bus" refers to a system that transports and distributes data. Different control modules are connected to the CAN-bus comfort system and CAN-bus system, depending on vehicle equipment. See appropriate System Wiring Diagrams article
3. Data is simultaneously transferred via the data lines (wires) "CAN-Hi" and "CAN-Lo" (Two line CAN-Bus). Depending on Bus-system version, theses wires are twisted together in order to minimize interference from other systems and shielded from other wires. See appropriate System Wiring Diagrams article
4. The wire connections between the control modules, via which data is transferred, are referred to as data wires.
5. Data is transferred to the connected control modules serially (one after the other) via these data wires, this data cannot be checked using workshop equipment.
6. Data is sent and excepted from various control modules in regular intervals as telegram (data message). Frequency between telegrams that a control module sends is dependent on the validity of the transferred data and is between 0.01 and 0.2 seconds.
7. If a connected control module obtains no information within a specified time period, or if received data signals cannot be evaluated, a malfunction is stored in the DTC memory.
8. The reception of the information e.g. "air conditioner" is displayed in measuring value block display groups 125 and 126. See «DISPLAY GROUP 125»(/audi/a4/b6-2000-2006/remont/communication-devices/#on-board-diagnostic-obd__display-group-125) .
9. If a control module cannot supply the required data (or only a specific information) available due to component malfunction, a malfunction notice is sent with data signal, which requires checking the DTC memory of the control module.

Example

The Outside Air Temperature Sensor -G17- is not connected, the Control module with indicator unit in instrument cluster -J285- therefore cannot sent the measuring value of this sensor in the data message.

The instrument cluster stores this malfunction and sends a malfunction notice instead of the measured value in data signal.

The A/C Control Head -E87- recognizes the malfunction notice when evaluating the telegram and stores "Instrument cluster, please check DTC memory".

CAN-bus comfort system, checking

Note. If the connector is removed from one control module connected to the CAN-bus system and the ignition is switched on, a malfunction entry can occur in another control module connected to the CAN-Bus. The same applies, if (e.g. by pulling a fuse) the voltage supply is interrupted. The Control module with indicator unit in instrument cluster -J285- is the interface between the two bus-systems. In addition -J285- is the decisive (determining) control module in the CAN-bus comfort system, via the adaptation function control modules that are connected to the CAN-bus comfort system are entered into this control module (-J285-) (depending on equipment level). => VAS 5051 Vehicle Diagnostic Testing and Information System You can determine how many control modules are connected to the CAN-bus system, based on the wiring diagram. See appropriate System Wiring Diagrams article

Isolating possible malfunction causes

Note. The following malfunction locations and malfunction types apply to the CAN-bus comfort system: VW-group CAN-bus comfort system Faulty: No data can be transferred via the Bus-system in single wire mode: No data can be transferred on of the one Bus-lines (CAN-Hi or CAN-Lo) Missing messages (time out for various control modules): No data was received by one or more control modules within a specified time period. Control module with indicator unit in instrument cluster Vehicle Electrical System Control Module -J519- Steering Column Electronic Systems Control Module -J527- Central control module for comfort system -J393- No communication No data is received from Control module with indicator unit in instrument cluster -J285-, Central control module for comfort system -J393, Vehicle Electrical System Control Module -J519 and/or Steering Column Electronic Systems Control Module -J527- Check DTC memory: Control module with indicator unit in instrument cluster -J285-, -J393-, -J519- or -J527- cannot send information due to a malfunction on a in serial connected component. Convertible Top Control Module -J256- No communication: No data is received from Convertible Top Control Module -J256- (Before continuing with further troubleshooting, check the coding of A/C control module -E87- and the installation of this optional equipment). Check DTC memory: Convertible Top Control Module -J256- cannot send information due to malfunction on a in serial connected component. CAN-bus system Check DTC memory: Control module with indicator unit in instrument cluster -J285- cannot send information, due to a malfunction on a control module connected to the CAN-bus system (Check DTC memory of instrument cluster control module).

Determining malfunction in CAN-bus comfort system

1. With ignition switched off connect VAS 5051 Vehicle Diagnostic, Testing and Information System with VAS 5051/1 diagnostic cable to 16-pin data link connector on vehicle. See «VAS 5051 VEHICLE DIAGNOSTIC, TESTING AND INFORMATION SYSTEM, CONNECTING AND SELECTING FUNCTIONS»(/audi/a4/b6-2000-2006/remont/communication-devices/#on-board-diagnostic-obd) .
2. Switch ignition on.
3. Press button -0- twice for function "Automatic test procedure".

Indicated on display of VAS 5051

Scheme 198

All address words stored in VAS 5051 are sent to the vehicle one after another via the diagnostic cable.

Indicated on display of VAS 5051

Scheme 199

1. Display field 1 shows which address word is currently transferred to VAS 5051.
2. Display field -2- shows which control modules answered. In addition the amount and type of malfunction stored in that control module is displayed.

1. Wait until "Function ended" is shown in display field -1-. NOTE: Before checking the CAN-bus wiring system, check whether a malfunction is stored in a control module which cannot exchange data with other control modules and eliminate malfunction as necessary. The data exchange with other control modules can be interrupted, if a control module stores a malfunction, although this malfunction may not apply to the CAN-bus-system. Check part number with index of control module that does not communicate.

Malfunction(s) on the CAN-bus comfort system are only indicated by the A/C Control Head -E87

1. Check coding of A/C Control Head -E87-, see «A/C CONTROL HEAD -E87-, CODING (FUNCTION 07)»(/audi/a4/b6-2000-2006/remont/communication-devices/#on-board-diagnostic-obd__ac-control-head-e87-coding-function)
2. Check data lines (wires) to A/C Control Head -E87- for open circuit or wiring resistance. Wire resistance: max: 1.5 Ohms See appropriate System Wiring Diagrams article NOTE: Watch for possible loose contact in the wiring and connectors. If no malfunction can be determined, malfunction is in A/C Control Head -E87-.

Malfunctions on the CAN-bus comfort system are indicated in another control module

1. Check data wires and respective shielding between the different control modules connected to the CAN-bus comfort system for open circuit and wiring resistance. Wire resistance: max: 1.5 Ohm See appropriate System Wiring Diagrams article
2. Check data wires and respective shielding between the different control modules connected to the CAN-bus comfort system for short circuit against each other, short to B+ and Ground (GND). See appropriate System Wiring Diagrams article See VAS 5051 Vehicle Diagnostic Testing and Information System NOTE: Watch for possible loose contact in the wiring and connectors. If this malfunction is not displayed on all connected control modules, it is possible that there is an open circuit at one connecting point in wiring. If no malfunction is determined and all other control modules connected to the CAN-bus comfort system show this malfunction, there is a malfunction in one of the connected control modules.
3. Check version, coding and the entered adaptation of Control module with indicator unit in instrument cluster -J285-. See VAS 5051 Vehicle Diagnostic Testing and Information System
4. Check version and coding of other control modules connected to the CAN-bus comfort system (e.g. Vehicle Electrical System Control Module -J519-, Steering Column Electronic Systems Control Module -J527-). See VAS 5051 Vehicle Diagnostic Testing and Information System
5. Disconnect all control modules from the CAN-bus system except the Control module with indicator unit in instrument cluster (interface to CAN-bus system) and the Steering Column Electronic Systems Control Module -J527-. See appropriate System Wiring Diagrams article
6. Erase DTC memory of Control module with indicator unit in instrument cluster. See VAS 5051 Vehicle Diagnostic Testing and Information System
7. Check DTC memory of instrument cluster and Steering Column Electronic Systems Control Module -J527-. See VAS 5051 Vehicle Diagnostic Testing and Information System If the malfunction on the CAN-bus comfort system no longer appears, malfunction is in one of the connected control modules.
8. Connect in sequence the different control modules again.
9. Check DTC memory after connecting each control module.
10. Replace control module if malfunction appears again after it has been connected again. If the malfunction on the CAN-bus comfort system is still displayed, there is malfunction in the Control module with indicator unit in instrument cluster or in the Steering Column Electronic Systems Control Module -J527-.
11. Disconnect Control module with indicator unit in instrument cluster and connect another (e.g. A/C control head -E87-). See appropriate System Wiring Diagrams article
12. Check DTC memory of Instrument Cluster again. NOTE: By disconnecting the instrument cluster and connecting another control module, a faulty module can be determined.
13. Replace faulty control module

Special tools and equipment

1. VAG 1598 A test box and VAG 1598/11 adapter cable and VAG 1598/12
2. VAS 5051 Vehicle diagnostic, Testing and Information System with VAS 5051/7 measuring leads, VAS 5051/8 DSO measuring cable and VAS 5051/9 Current pick-up clamp 50 A
3. VAG 1527 B Voltage Tester
4. VAG 1594 A connector test kit
5. Temperature sensor with suitable tester

Connect VAG 1598 A test box to wiring harness connectors of A/C Control Head -E87

Note. The adapters from VAG 1598 A test box must not be connected to the A/C Control Head E87- during the On Board Diagnostic (OBD).

Scheme 200

1. Switch ignition off.
2. Remove A/C Control Head -E87-. See «A/C CONTROL HEAD -E87-, REMOVING AND INSTALLING»(/audi/a4/b6-2000-2006/remont/automatic-hvac-system/#air-conditioning__ac-control-head-e87-removing-and) .
3. Connect VAG 1598/11 adapter cable and VAG 1598/12 to disconnected harness connectors of A/C Control Head -E87-. NOTE: DO NOT connect A/C control head -E87-. To carry out the measurement, connect the VAG 1598 A test box to relevant adapter lead. The socked assignment on VAG 1598/12 adapter corresponds exactly to the terminal assignment on the A/C Control Head -E87-. The socked assignment on VAG 1598/11 adapter does not corresponds exactly to the terminal assignment on the A/C Control Head -E87-. See «SOCKET ASSIGNMENT FOR VAG 1598 A TEST BOX WITH ADAPTER LEAD VAG 1598/11»(/audi/a4/b6-2000-2006/remont/communication-devices/#on-board-diagnostic-obd__socket-assignment-for-vag-1598-a) .

Socket assignment for VAG 1598 A test box with adapter lead VAG 1598/11

Note. The terminal assignment for connectors A and B on the VAG 1598/11 adapter does not match the socket assignment on the VAG 1598 A test box. The terminal assignment for connector C on the VAG 1598/11 adapter matches exactly the socket assignment on the VAG 1598 A test box. The terminal assignment for connector D on the VAG 1598/12 adapter matches exactly the socket assignment on the VAG 1598 A test box. Because the connectors for the A/C Control Head -E87- are distributed over two adapter cables ((VAG 1598/11 and 12) there is no Ground (GND) connection for testing purposes when VAG 1598/11 adapter cable is connected. Therefore, for various steps of the electrical test it is necessary to use a suitable Ground connection point on the body of the car, or to use a second VAG 1598 test box. With the VAG 1598/12 adapter the Ground (GND) connection is through terminal 13).

SOCKET ASSIGNED FOR VAG 1598 A TEST BOX WITH ADAPTER LEAD VAG 1598/11

Test requirement

1. All fuses OK

See appropriate System Wiring Diagrams article

1. VAG 1598/11 adapter cable and VAG 1598/12 connected to disconnected harness connectors of A/C Control Head -E87-.

Scheme 201

Scheme 202

1. Select operating mode "Test instrument" on VAS 5051 Vehicle Diagnostic, Testing and Information System
2. Select during the variable test steps the required test instrument types, by clicking the relevant button on VAS 5051 display.

Electrical tests (to be performed on A/C Control Head -E87-) overview

Note. A variety of information is sent via the CAN-bus comfort system, no electrical testing applies for this information, see READ MEASURING VALUE BLOCK (FUNCTION 08) .

Scheme 203

Test step 1

Voltage supply and Ground (GND) connection of A/C Control Head -E87

Scheme 204

Scheme 205

Scheme 206

Scheme 207

Note. The wiring connection to these sensors terminate on different connectors, for this reason use a second VAG 1598 A test box or connect the measuring unit direct to VAG 1598/12 using a suitable test lead from the VAG 1594 A.

Temperature depending resistance values of sensor / sender

TEMPERATURE DEPENDING RESISTANCE VALUES OF SENSOR/SENDER

Test step 3

Voltage supply and wiring connection to Control module for fresh air blower -J126- and to Fresh Air Blower -V2

Scheme 208

1. Switch ignition off.
2. Remove glove compartment. See «GLOVE COMPARTMENT, REMOVING AND INSTALLING»(/audi/a4/b6-2000-2006/remont/mirrors/#interior-equipment-except-cabriolet__glove-compartment-removing-and-installing) (except Cabriolet), or «GLOVE COMPARTMENT LOCK HANDLE (VEHICLES WITH KNEE BOLSTER), REMOVING AND INSTALLING»(ref-197209-S02785761182005101300000) for the Cabriolet.
3. Disconnect connector (A) from Control module for fresh air blower -J126- (B).
4. Measure voltage between terminal -4- and terminal -3- on connector -A- Specification: Battery voltage

Note. If voltage is below battery voltage, repair voltage and Ground (GND) connection according to wiring diagram. On vehicles with sunroof with solar cells, with the sunroof closed the generated voltage of the solar cells is present on terminal 6 of the connector. The Control module for fresh air blower -J126- is continuously monitored by the A/C control head -E87-, if a malfunction occurs, this will be stored in the DTC memory. The current status of Fresh Air Blower -V2- is displayed in the measuring value block. See READ MEASURING VALUE BLOCK (FUNCTION 08) (display group 018).

Scheme 209

Scheme 210

Air conditioner positioning motors with potentiometers

Note. The resistance value of potentiometer in the positioning motors (Specification: 3.6 to 5.7 kohms. Between terminal 1 and 3 can only be measured at the motors themselves (they are connected in parallel). The resistance value of the potentiometers in the positioning motors (between terminals 1 and 2 and between terminals 3 and 2) depends on the position of the positioning motor, and must always be measured with the positioning motor installed. The upper specified value is not obtained in test steps 4.1 and 4.2. (In order to reach the upper specified value, all harness connectors from other positioning motors must be disconnected during the measurement (switched in Parallel). If the A/C Control Head -E87- detects the malfunction "Potentiometer short circuit to Ground (GND)" or "Open/short circuit to B+", check all the potentiometers and the wiring. If DTC memory recognizes several positioning motors as faulty and the malfunction cannot be detected in test step 4, check potentiometers in all positioning motors and the wiring connection between the positioning motors for short circuit (e.g. with harness connectors disconnected between -V107- and -V70- and -E87- between socket 1, 2 and 3 in pertaining connector the tester must read infinity ohms.

Scheme 211

Scheme 212

Scheme 213

Scheme 214

Scheme 215

Test step 5

Pressure signal from High Pressure Sensor -G65

Scheme 216

Scheme 217

Scheme 218

Note. If refrigerant circuit is correctly filled the pressure and therefore the duty cycle changes with ambient temperature. The duty cycle and the calculated pressure by A/C Control Head -E87- is displayed in the measuring value block. See READ MEASURING VALUE BLOCK (FUNCTION 08) (display group 001). The signal that is transferred when the pressure in the refrigerant circuit is approximately 5 to 6 bar, corresponds to an approximate duty cycle of 22% (with compressor not engaged, an ambient temperature of 20°C and properly filled refrigerant circuit) The signal that is transferred when the pressure in the refrigerant circuit is approximately 16 bar, corresponds to an approximate duty cycle of 50%. This is obtained with the compressor not engaged and under extreme conditions (e.g. very ambient temperatures and a hot engine).

Checking pressure signal from High Pressure Switch -G65

The oscilloscope shows this display when the following conditions are met.

Scheme 219

Scheme 220

1. Ignition switched on (B+ and Ground available at High Pressure Switch -G65-)
2. Setting on oscilloscope: 5 V/Div. = (5V per unit DC voltage) 5 ms/Div. (5 milliseconds per unit)
3. Measuring lead (signal lead) connected to socket -7- of test box.
4. Measuring lead (shielded wire) connected to socket -14- of test box (Ground (GND)). NOTE: The display shows a signal that is transferred when the pressure in the refrigerant circuit is approximately 7 bar, it corresponds to an approximate duty cycle of 25% (with compressor not engaged, an ambient temperature of 30°C and properly filled refrigerant circuit) The impulse width -A- depends on the pressure in the refrigerant circuit (if pressure increases, area -A- is getting wider). The signal distance -B- is always 20 milliseconds (corresponds to frequency of 50 Hertz). The duty cycle is determined by the ratio of impulse width -A- and signal distance -B-.

Connector assignment at High Pressure Switch -G65

Terminal 1: Ground (GND)

Terminal 2: Signal output (square wave signal to -E87-)

Terminal 3: B+ (terminal 75)

Scheme 221

Note. With harness connector -B- disconnected, the compressor will not engage. The high pressure sensor -A- is an electronic control module, which creates a square wave signal, the duty cycle ratio changes with pressure in the refrigerant circuit. See PRESSURE SIGNAL FROM HIGH PRESSURE SENSOR -G65 .

Pressure signal from High Pressure Sensor -G65

A- "Refrigerant system pressure, high pressure side" in bar (absolute pressure)

B- Signal ratio of square wave signal

C- Characteristic curve

Scheme 222

Note. The A/C control head -E87- switches the compressor on as soon as no compressor cut-off condition exists (by activating the A/C Compressor Regulator Valve -N280-): If the duty cycle is greater than 12% (absolute pressure corresponds approx.; 1.8 bar), if smaller than 87.5% (pressure corresponds to approx.: 32 bar). The compressor is not switched on if the duty cycle is smaller than 12 % or greater than 87.5 % (A/C Compressor Regulator Valve -N280- is not activated). The duty cycle and the calculated pressure by A/C Control Head -E87- is displayed in the measuring value block, see READ MEASURING VALUE BLOCK (FUNCTION 08) (display group 001). 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 A/C Control Head -E87- sends the request to switch on the coolant fans to the Engine Control Module (ECM) via the CAN-bus comfort system, the ECM switches via the coolant fan control module the coolant fans on. Independent from pressure in refrigerant circuit as soon as compressor is switched on. The A/C Control Head -E87- sends the request for increased coolant fan speed to the Engine Control Module (ECM) via the CAN-bus comfort system: Vehicles with gas engines request 100% fan speed currently at approx.: 26 bar pressure in the refrigerant circuit. The signal generated from High Pressure Sensor -G65- is also used to control the engine. The A/C Control Head -E87- sends the information to the Engine Control Module (ECM) via the CAN-bus comfort system (the necessary torque to drive the compressor depends on the pressure in the refrigerant circuit). The signal is displayed as duty cycle in measuring value block depending on ECM version.

See VAS 5051 Vehicle Diagnostic Testing and Information System

Scheme 223

Scheme 224

Scheme 225

Note. During operation the compressor performance is dependent on the A/C Compressor Regulator Valve -N280-. The A/C Control Head -E87- controls the current that flows through the regulator valve and therefore the compressor performance (output). See READ MEASURING VALUE BLOCK (FUNCTION 08) (display group 001).

Scheme 226

Scheme 227

Scheme 228

1. Switch ignition off.
2. Connect A/C control head to vehicle wiring harness.
3. Disconnect harness connector on A/C compressor.
4. Recreate connection to regulator valve between connector A and connector B, using adapter cable from VAG 1594 A connector test kit. NOTE: You can create an adapter cable for this test. E.g. use connectors A and B (part number 1J0 973 702 and 1J0 973 802 and relevant terminal contacts), two suitable sockets for connectors C and two 0.5 mm 2 diameter wires.
5. Connect DSO-measuring cable VAS 5051/8 to two adapter cable. Measuring cable (signal wire) to terminal -2-. Measuring cable (shielded, ground) to terminal -1-.
6. Select operating mode "Test instrument" on VAS 5051: DSO (Digital Storage Oscilloscope) on
7. Setting 5V/Div =, 5ms/Div (5 volt DC voltage and 5 milliseconds per unit)
8. Start engine
9. Select preset temperature to "Lo" on A/C control head.
10. Switch activation of A/C Compressor Regulator Valve -N280- on and off, by pressing the "Auto" and "Econ" button on the A/C Control Head -E87-. Depending on button pressed on A/C Control Head -E87- the oscilloscope displays
11. During operating mode "OFF" of "Econ" no square wave signal (the regulator valve is not activated).
12. During operating mode "Auto" and temperature selection "Lo" a square wave signal with an impulse width -A- between 75% and 100% (the regulator valve is activated) NOTE: The illustration shows a signal with a duty cycle ratio of approx. 80%. The impulse width -A- is dependent of the required cooling performance, the vehicle voltage etc. (via the width of range -A- the current is regulated through A/C Compressor Regulator Valve -N280- by the A/C Control Head -E87-. The signal distance -B- is always 2 milliseconds (corresponds to frequency of 500 Hertz). The duty cycle is determined by the ratio of impulse width -A- and signal distance -B-.
13. The impulse width of the square wave signal changes depending on the selection on the A/C Control Head -E87- and measured surrounding conditions (duty cycle between 100% and greater than 30%, the regulator valve is so activated that the necessary compressor output is reached to attain the selected temperature). NOTE: During operating mode "Auto" and temperature selection "Lo" the A/C Compressor Regulator Valve -N280- is activated in such a way that the maximum permissible current of 0.8 A flows through -N280- (maximum compressor output). In controlled operation, the activation period is dependent on the requested cooling performance, the vehicle voltage etc. The activation period is at least so long that an average current of 0.3 A flows.

Scheme 229

Scheme 230

Scheme 231

Heated rear window -Z1-, testing

Note. If a condition exists which disables the heated rear window to be switched on (short circuit in wiring to rear window, open circuit in voltage supply to A/C control head -E87- or the an open top on convertible) the indicator light in the button of the A/C control head -E87- illuminates when pressing the button, and goes out after button has been released, the heated rear window however is not switched on. If voltage on terminal "30" measured by the A/C control head -E87- drops below 12.5 volt, the performance of the heated rear window is reduced and the generator load is reduced (the electronic of the A/C control head -E87- reduces the activation from 100% to 90% - 10%).

1. VAS 5051 Vehicle Diagnostic, Testing and Information System (with current clamp)
2. VAG 1594 A connector test kit

1. All fuses OK

Scheme 232

1. Switch ignition off.
2. Remove A/C Control Head -E87-. See «A/C CONTROL HEAD -E87-, REMOVING AND INSTALLING»(/audi/a4/b6-2000-2006/remont/automatic-hvac-system/#air-conditioning__ac-control-head-e87-removing-and) .
3. Disconnect connectors -D- and -F- from A/C control head -E87
4. Connect adapter cable VAG 1598/12 of test box to disconnected harness connector -D-.
5. Connect VAG 1598 A test box to VAG 1598/12 adapter cable
6. Measure voltage between terminal 5 of connector -F- and socket 13 (Ground connection) of test box. Specification: approx. battery voltage
7. Measure resistance between terminal 6 of connector -F- and socket 13 (Ground connection) of test box. Specification: Resistance approx. 0.5 to 1.0 ohms(Ohm) NOTE: Resistances value smaller than 10ohms. cannot be measured accurately with shop tools, a short circuit in the wiring connection or in the Heated Rear Window -Z1- cannot be detected If the resistance value is too large, check and eliminate open circuit in wiring connection to Heated Rear Window -Z1-. See appropriate System Wiring Diagrams article
8. Connect harness connectors -D- and -F- to A/C control head -E87- (all connectors are now connected to the -E87-).
9. Guide wire of connector -F- terminal "6" through current clamp 50 A of VAS 5051/9.
10. Select operating mode "Test instrument" on VAS 5051: Current 50 A current clamp on. NOTE: All harness connectors on A/C control head -E87- must be connected.
11. Start engine.
12. Switch rear window heating on via A/C control head -E87- (indicator lamp in button lights up). Specification: The display on the VAG1715 will change from approx. 0 amps to less than 25 amps.
13. Wait approx. 12 minutes. Specification: The display changes from less than 25 amps to approx. 0 amps (indicator lamp in button goes out). NOTE: The current probe may be influenced by stray current which could cause the display to show a low current reading when rear window heating is switched off. The heated rear window stays switched on with outside temperatures up to 0°C until ignition is switched off (heated rear window can be manually switched off anytime). If the temperature increases above 0°C during a driving cycle, the heated rear window will be switched off after the specified operating time -E87-) of approx.: 12 minutes elapsed. With outside temperatures greater than 0°C the heated rear window is switched off automatically by the -E87- after the programmed operating time (approximately 12 minutes) has elapsed.

Heated seats, testing

Note. If voltage on terminal "30" measured by the A/C control head -E87- drops below 12.5 volts, the performance of the heated seats is reduced and the generator load is reduced (the electronics of the A/C control head -E87- also reduces duty cycle of the activation from 100% to 90% - 10% if the specified seat temperature has not yet been reached).

1. VAG 1598 A test box and VAG 1598/11 adapter cable and VAG 1598/12
2. VAS 5051 Vehicle Diagnostic, Testing and Information System with VAS 5051/7 test leads
3. VAG 1594 A connector test kit

Scheme 233

Scheme 234

1. Switch ignition off.
2. Remove A/C Control Head -E87-. See «A/C CONTROL HEAD -E87-, REMOVING AND INSTALLING»(/audi/a4/b6-2000-2006/remont/automatic-hvac-system/#air-conditioning__ac-control-head-e87-removing-and) .
3. Connect VAG 1598 A test box with VAG 1598/11 adapter cable to connector -C-. See «WIRING AND COMPONENT TESTING USING VAG 1598 A TEST BOX»(/audi/a4/b6-2000-2006/remont/communication-devices/#on-board-diagnostic-obd) .
4. Connect VAG 1598/12 adapter cable to connector -D- (use a second VAG 1598 A test box or connect tester directly to VAG 1598/12 using suitable test leads from VAG 1594 A connector test kit, see «WIRING AND COMPONENT TESTING USING VAG 1598 A TEST BOX»(/audi/a4/b6-2000-2006/remont/communication-devices/#on-board-diagnostic-obd) . NOTE: The terminal assignment of connector -C- on VAG 1598/11 adapter cable and connector -D- on VAG 1598/12 adapter cable is identical with the socket assignment on VAG 1598 A test box.
5. Measure resistance between terminal 5 in connector -C- (to Drivers Heated Seat Temperature Sensor -G59-) and terminal 16 in connector -D- (Ground connection) on the test boxes. Specification: Resistance greater than 1.5 kohms (Kilo-Ohm) and smaller than 25 k ohms (depending on the temperature of the temperature sensor, at seat temperature of 20° C the measuring value is at approx. 10 kohms)
6. Measure resistance between terminal 6 in connector -C- (to Passengers Heated Seat Temperature Sensor -G60-) and terminal 16 in connector -D- (Ground connection) on the test boxes. Specification: Resistance greater than 1.5 kohms (Kilo-Ohm) and smaller than 25 kohms (depending on the temperature of the temperature sensor, at seat temperature of 20° C the measuring value is at approx. 10 kohms) NOTE: The resistance value of the temperature sensor in the heating elements changes with the temperature (the specifications in the following table are approximate values). HEATED SEAT TEMPERATURE SENSOR: TEMPERATURE VERSUS RESISTANCE SPECIFICATIONS Temperature at temperature sensor in seat in °C Resistance value of temperature sensor in kΩ 20 10 30 6.0 40 4.2 50 2.8 60 1.7 If the resistance value is too large, check and eliminate open circuits or contact resistance in wiring connection to heating elements of heated seats. If open circuit is in seat, repair seat. See appropriate System Wiring Diagrams article See «SEATS FRAMES - EXCEPT CABRIOLET»(/audi/a4/b6-2000-2006/remont/seats/#seats-frames-except-cabriolet) See «SEATS FRAMES - CABRIOLET»(/audi/a4/b6-2000-2006/remont/seats/#seats-frames-cabriolet)

1. VAS 5051 Vehicle Diagnostic, Testing and Information System (with current clamp)
2. VAG 1594 A connector test kit

1. All fuses OK

See appropriate System Wiring Diagrams article

Scheme 235

Scheme 236

Scheme 237

1. Switch ignition off.
2. Remove A/C Control Head -E87-. See «A/C CONTROL HEAD -E87-, REMOVING AND INSTALLING»(/audi/a4/b6-2000-2006/remont/automatic-hvac-system/#air-conditioning__ac-control-head-e87-removing-and) .
3. Disconnect connectors -D- and -F- from A/C control head -E87
4. Connect adapter cable VAG 1598/12 of test box to disconnected harness connector -D-.
5. Connect VAG 1598 A test box to VAG 1598/12 adapter cable
6. Measure voltage between terminal 3 of connector -F- and socket 13 (Ground connection) of test box. Specification: approx. battery voltage
7. Measure resistance between terminal 1 of connector -F- and socket 13 (to heating element in drivers seat) of test box. Specification: Resistance approx. 1.5 - 2.5 (25) ohms (Ohm)
8. Measure resistance between terminal 2 of connector -F- and socket 13 (to heating element in passenger seat) of test box. Specification: Resistance approx. 1.5 - 2.5 (25) ohms (Ohm) NOTE: Through contact resistance on different connector, resistance values of approx. 25ohms can be measured. The contact resistance is lowered as soon as a voltage of 12 volts is applied and the function of the heated seats is not affected. The resistance value of the heating elements in the seat changes with the temperature (at seat temperature of 20° C the resistance value is approx. 1.9 ohms). Resistance values smaller than 10ohms. cannot be measured accurately with shop tools, a short circuit in the wiring connection or in the heating elements of the heated seats cannot be detected. If the resistance value is too large, check and eliminate open circuits in wiring connection to heating elements of heated seats. If open circuit is in seat, repair seat. See appropriate System Wiring Diagrams article. See «SEATS FRAMES - EXCEPT CABRIOLET»(/audi/a4/b6-2000-2006/remont/seats/#seats-frames-except-cabriolet) , or See «SEATS FRAMES - CABRIOLET»(/audi/a4/b6-2000-2006/remont/seats/#seats-frames-cabriolet)
9. Connect harness connectors -D- and -F- to A/C control head -E87- (all connectors are now connected to the -E87-).
10. Guide wire of connector -F- terminal "1" through current clamp 50 A of VAS 5051/9.
11. Select operating mode "Test instrument" on VAS 5051: Current 50 A current clamp on.
12. Bring both thumbwheel for heated seats (on -E87-) to position "0". NOTE: All harness connectors on A/C control head -E87- must be connected. Start engine. Move thumbwheel for heated drivers seat to position "6". Specification: The display will change from approx. 0 amps to less than 10 amps. Move thumbwheel for heated drivers seat to position "0". Specification: The display will change from approx. 10 amps to less than 0 amps. Guide wire of connector -F- terminal "2" through current clamp 50 A of VAS 5051/9. Move thumbwheel for heated passenger seat to position "6". Specification: The display will change from approx. 0 amps to less than 10 amps. Move thumbwheel for heated passenger seat to position "0". Specification: The display will change from approx. 10 amps to less than 0 amps. NOTE: The current probe may be influenced by stray current which could cause the display to show a low current reading when the heated seat is switched off. If an open circuit or short circuit exists in the connection to the temperature sensor in the seat, the output to the heating element is not switched by the A/C control head -E87-. The A/C control head -E87- does not switch on the heater, if a short circuit to Ground in the heating element or the wiring connection exists (the heater is switched off immediately as soon as a large current flows).

Heated front window -Z2-, checking activation

Special tools and equipment

1. VAG 1598 A test box and VAG 1598/11 adapter cable and VAG 1598/12
2. VAS 5051 Vehicle Diagnostic, Testing and Information System with VAS 5051/7 test leads
3. VAG 1594 A connector test kit

Scheme 238

Scheme 239

1. Switch ignition off.
2. Remove A/C Control Head -E87-. See «A/C CONTROL HEAD -E87-, REMOVING AND INSTALLING»(/audi/a4/b6-2000-2006/remont/automatic-hvac-system/#air-conditioning__ac-control-head-e87-removing-and) .
3. Connect VAG 1598 A test box with VAG 1598/11 adapter cable between connector -C- and A/C control head -E87-. See «WIRING AND COMPONENT TESTING USING VAG 1598 A TEST BOX»(/audi/a4/b6-2000-2006/remont/communication-devices/#on-board-diagnostic-obd) .
4. Connect VAG 1598/12 adapter cable between connector -D- and A/C control head -E87- (use a second VAG 1598 A test box or connect tester directly to VAG 1598/12 using suitable test leads from VAG 1594 A connector test kit. See «WIRING AND COMPONENT TESTING USING VAG 1598 A TEST BOX»(/audi/a4/b6-2000-2006/remont/communication-devices/#on-board-diagnostic-obd) . NOTE: The terminal assignment of connector -C- on VAG 1598/11 adapter cable and connector -D- on VAG 1598/12 adapter cable is identical with the socket assignment on VAG 1598 A test box.
5. Start engine. NOTE: All harness connectors on A/C control head -E87- must be connected.
6. Measure voltage between terminal 8 in connector -C- (Heated Windshield Control Module -J505-) and terminal 16 in connector -D- (Ground connection). Specification: approx. battery voltage NOTE: If a voltage of less than 5 volts is measured, the Heated Windshield Control Module -J505- is currently not ready to switch on the front window heater or there is a short circuit to Ground (GND) in the connection to -J505-, see «WINDSHIELD DEFROSTER»(/audi/a4/b6-2000-2006/remont/communication-devices/#on-board-diagnostic-obd) . If a voltage between 5 volts and 8 volts is measured the A/C control head -E87- activates the -J505- and the -J505- switches on the windshield defroster.

Windshield defroster, function

1. The Heated Windshield Control Module -J505- is activated by the A/C control module (see «READ MEASURING VALUE BLOCK (FUNCTION 08)»(/audi/a4/b6-2000-2006/remont/communication-devices/#on-board-diagnostic-obd__read-measuring-value-block-function-08) , display group 015): After each cold start of the engine if the outside temperature is smaller than +5° C and "Auto" mode has been selected on the A/C control head -E87-. The temperature of the A/C control head -E87- has to bet set so that the air conditioning is in heating mode and none of the vent temperature sensors (-G150-, -G151-, -G261- and -G262-) should measure more than +35° C. Depending on the outside temperature, the heating period is maximum 6 minutes (at -4° C). When selecting "Defrost" mode on the A/C control head -E87- and if outside temperature is smaller than +5° C. Depending on the outside temperature the heating period is between 2 and 6 minutes. As long as the windshield defroster is switched on, the indicator control light in the "Defrost" button flashes. The activation occurs only with engine running.
2. The Heated Windshield Control Module -J505- switches on the windshield defroster, if the following conditions are met. The A/C Control Head -E87- controls the Heated Windshield Control Module -J505-. The voltage on Heated Windshield Control Module -J505- is greater than 12.70 volts. Heated Windshield Control Module -J505- is not overheated.
3. The Heated Windshield Control Module -J505- directs approx. battery voltage to the A/C control head -E87-, with this signal the -E87- recognizes, that -J505- is ready to switch on the windshield defroster. If this voltage is cut in half (to approx. 5 to 8 volt) the Heated Windshield Control Module -J505- switches the windshield defroster on.
4. The electrical resistance of the metal foil in windshield defroster -Z2- is approx. 2.3 Ohms. In order to attain a maximum heating performance of approx. 1000 W (Watts) on the front windshield, it is necessary that the voltage is greater than the vehicle electrical system. The Heated Windshield Control Module -J505- changes the vehicle electrical voltage into a variable voltage, this variable voltage is between 25 and 48 volts depending on the vehicle electrical voltage.
5. To avoid an overload on the vehicle electrical system, the -J505- regulates the heating output of the windshield defroster, at vehicle voltage of 12.70 the output is approx. 200 W and is gradually increased to 1000 W at 13.10 volts. To avoid the vehicle electrical system from collapsing when the windshield defroster is switched on, the Heated Windshield Control Module -J505 allows for an output increase of 200 W per second.
6. To avoid the Windshield defroster -Z2- from being activated if there is a short circuit or an open circuit, the Heated Windshield Control Module -J505- checks the resistance of the windshield defroster -Z2-. If the measured resistance is smaller than approx. 1.7 ohms (short circuit) or greater than approx. 3.3 ohms (open circuit or contact resistance) the Heated Windshield Control Module -J505- does not switch on or off the heater.

Windshield defroster, disabling

Note. The Heated Windshield Control Module -J505- is installed in the fresh air plenum beneath the battery. In the event that the front windshield has a crack (e.g. hit by stone), the heating of the front windshield must be disabled to avoid further cracking of windshield. The A/C control head -E87- does not regulate the Heated Windshield Control Module -J505- in "Econ" operating mode. To avoid a restriction of the air conditioning function, the activation of the Heated Windshield Control Module -J505- has to be interrupted until the damaged windshield defroster -Z2- is replaced. To do this disconnect connector -A- from control module -B-.

1. The sensor for air quality detects pollutants in the ambient air (mostly gasoline and or diesel exhaust) and orders the A/C Control Head -E87- to switch the air conditioning system to recirculated air mode.
2. The A/C Control Head -E87- receives a signal from the Sensor for air quality -G238- from which the type and amount of air pollution is determined. Depending on the outside temperature and the air pollution strength, the A/C control head then decides: At an outside temperature greater than approx. + 2° C (36° F) the recirculated air mode becomes switched on when there is only a slight increase in pollutant concentration. At an outside temperature of between approx.: + 2° C (36° F) and approx.: - 8° C (-18° F) the recirculated air mode only becomes switched on when there is a stronger increase of pollutant concentration (compressor is switched on simultaneously). At an outside temperature of less than - 8° C (-18° F) the change-over also only occurs after an increase of pollutants concentration and only for another 15 seconds (the compressor is not switched-on). If the concentration of pollutants decreases, the climate control system switches over again to the fresh air mode. The function "Automatic air recirculation" can be switched off at any time. If the function is active and there is a request for "Automatic recirculated air", the compressor is also switched on when outside temperature is less than + 2° C. Compressor operation is no longer possible with temperatures lower than approx. - 8° C. On vehicles with "Automatic air recirculation", the compressor can be switched on up to a temperature of approx. - 8° C when recirculated air is manually switched on (via recirculation button). 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 learning (it adjusts its sensitivity to the ambient conditions). If outside air pollution load remains high for longer period of time, the sensor starts to adapt it self 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. The climate control system may also operate for a longer period of time in air recirculation mode, if more load peaks occur after another.
3. A specific amount of time is needed for the A/C flaps to change over. In the event that a sudden increase in pollutants is encountered (e.g. when driving through a diesel exhaust cloud) gas forming 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. See «DUST AND POLLEN FILTER ELEMENT, REMOVING AND INSTALLING»(/audi/a4/b6-2000-2006/remont/automatic-hvac-system/#air-conditioning__dust-and-pollen-filter-element-removing) .
4. In order to avoid frequent shifting of the recirculated air/fresh air flap, a slight increase of pollutants in the ambient air will not allow for immediate shifting (the sensor does not send a request to A/C Control Head -E87-). The filter affect of the active charcoal insert in the dust and pollen filter will be sufficient. See «DUST AND POLLEN FILTER WITH ACTIVE-CARBON-FILTER ELEMENT»(/audi/a4/b6-2000-2006/remont/automatic-hvac-system/#air-conditioning__dust-and-pollen-filter-with-active-carbon-filter) .
5. In order to avoid frequent shifting of the recirculated 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 recirculated air mode is no longer necessary.
6. If the compressor is shut-off (e.g. in "Econ mode"), the maximum duration of the "Automatic recirculated air" mode is limited to approx. 15 seconds by the A/C control head -E87- to avoid windows from fogging up.
7. In order to clear foggy windows as quick as possible, the A/C Control Head -E87- does not switch to recirculated air mode when in "Defrost" mode.
8. After the ignition is switched on, the Sensor for air quality -G238- requires approx. 30 seconds to be operational (warm-up time). During this time there is no requirement from the sensor to A/C Control Head -E87- for "Automatic recirculated air" mode.
9. 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. Therefore, do not install sensors that were in contact with such substances.

1. VAS 5051 Vehicle Diagnostic, Testing and Information System with VAS 5051/1 diagnostic cable
2. Test gas bottle D 007 855 A2

1. Vehicle is in area where there is clean recirculating air (not near running engines, openings from exhaust systems, etc.)
2. Engine compartment and plenum chamber are clean (not contaminated with oil and/or fuel).
3. The engine compartment and fresh air plenum chamber were not sprayed with cleaning or preservative solutions.

Scheme 240

1. With ignition switched off connect VAS 5051 Vehicle Diagnostic, Testing and Information System with VAS 5051/1 diagnostic cable to 16-pin data link connector on vehicle. See «VAS 5051 VEHICLE DIAGNOSTIC, TESTING AND INFORMATION SYSTEM, CONNECTING AND SELECTING FUNCTIONS»(/audi/a4/b6-2000-2006/remont/communication-devices/#on-board-diagnostic-obd) .
2. Start engine.
3. Check DTC memory. See «DIAGNOSTIC TROUBLE CODE (DTC) MEMORY, CHECKING (FUNCTION 02)»(/audi/a4/b6-2000-2006/remont/communication-devices/#on-board-diagnostic-obd__diagnostic-trouble-code-dtc-memory-checking) .
4. Select "Auto" operating mode on A/C Control Head -E87
5. The button for "Automatic recirculated air" -A- is activated (lamp in -A- button comes on).
6. Wait 30 seconds (warm up time of sensor for air quality -G238-).

Indicated on display of VAS 5051

Scheme 241

1. Press buttons -0- and -8- to select "Read Measuring Value Block" function 08.
2. Remove plenum cover.

Indicated on display of VAS 5051

Scheme 242

1. Display field -1- indicates request to input display group.
2. Display field -2- shows input keyboard.

Scheme 243

1. Input via keyboard in display field 2 the desired display group umber "014" (see overview of selectable display group numbers. See «OVERVIEW OF SELECTABLE DISPLAY GROUP NUMBERS»(/audi/a4/b6-2000-2006/remont/communication-devices/#on-board-diagnostic-obd) ).
2. Press -Q- button to confirm input.
3. Read indications shown in display fields -3- and -4-. NOTE: Display field -4- shows the operating conditions of fresh air/recirculated flap and display field -3- shows the condition of the air quality sensor signal. Table of possible displays. See «DISPLAY GROUP 014»(/audi/a4/b6-2000-2006/remont/communication-devices/#on-board-diagnostic-obd__display-group-014) . Specified value in display field -4-: 00 (no request for "Recirculated air mode", air conditioning in fresh air mode) or Specified value in display field -4-: 60 ("Partial recirculated air mode", fresh air and recirculated air flap open)
4. Place spray head -A- of test gas bottle over air inlet of sensor for air quality -B- (with version "1").
5. Place spray head -A- of test gas bottle over air inlet of sensor for air quality -B- (with version "2").
6. Press spray head -C- of test gas bottle for 1 second. NOTE: The content of the test bottle consists of pure oxygen with a specified amount of nitrogen oxide. The sensor for air quality is in different housings, version "1" was installed at beginning of production. This sensor was replaced in a running change to version "2", however it has the same function. If the sensor comes in contact with cigarette smoke or gas from a lighter (gas is heavier than air, therefore remove and rotate sensor) it will react.
7. Read value indicated in display field -4-. Specification: 10: (request for "Automatic recirculated air" mode present, request is fulfilled, A/C changes to recirculated air mode)
8. Wait a short period time (approx. 1 minute, depending on amount of test gas sprayed in sensor).
9. Read value indicated in display field -4-. Specification: 00: (no request for "Recirculated air mode", air conditioning in fresh air mode) or Specification: 60 (Partial recirculated air mode) NOTE: In order to avoid frequent shifting of the recirculated air/fresh air flap, the request from the sensor for "Automatic recirculated air" mode remains for at least 25 seconds (minimum duration period), even if the pollutant concentration in the air is so far reduced, that recirculated air mode would be no longer necessary.
10. Operate switch for wiper/washer system until windshield washer pump -V5- delivered washer fluid for approx. 2 seconds.
11. Read value indicated in display field -4-. Specification: 30: (Request for "Recirculated air" mode due to washer/wiper system, A/C switches for approx. 10 seconds to the recirculated air mode)
12. Wait a short period time.
13. Read value indicated in display field -4-. Specification: 00: (no request for "Recirculated air mode", air conditioning in fresh air mode) or Specification: 60 (Partial recirculated air mode) NOTE: Depending on the composition of the windshield washer fluid, the sensor can determine impurities in the air and request for "Automatic air recirculation". When activating the wiper/washer system and the system does not change-over to recirculated air mode, check function of Wiper/Washer Intermittent Relay -J31- (the information "windshield washing" is received from the Steering Column Electronic Systems Control Module -J527- via the CAN-bus comfort system) => (Read Measuring Value Block, display group 018). NOTE: If the functions of the Sensor for air quality -G238- is OK for this test and there is a customer complaint continue as follows: Check dust and pollen filter for dirt. Connect VAS 5051 and select "Read measuring value block" function 08. A second technician is required because the indicated values must be read out in the vehicle interior. Observe safety precautions. See «SAFETY PRECAUTIONS»(/audi/a4/b6-2000-2006/remont/communication-devices/#on-board-diagnostic-obd__safety-precautions) . Enter display group number "014". Drive vehicle to area with relatively clean ambient air (system operates in fresh air mode). Now drive vehicle into an area with heavily polluted recirculated air (e.g. on a street construction or truck traffic). Read indications shown in display fields -3- and -4-. Display fields -3- and -4- must change when driving through a diesel exhaust cloud (meaning: see «OVERVIEW OF SELECTABLE DISPLAY GROUP NUMBERS»(/audi/a4/b6-2000-2006/remont/communication-devices/#on-board-diagnostic-obd) , display group 014). Read descriptions on «DUST AND POLLEN FILTER WITH ACTIVE-CARBON-FILTER ELEMENT»(/audi/a4/b6-2000-2006/remont/automatic-hvac-system/#air-conditioning__dust-and-pollen-filter-with-active-carbon-filter) and «SENSOR FOR AIR QUALITY -G238»(/audi/a4/b6-2000-2006/remont/communication-devices/#on-board-diagnostic-obd) .

See also:
• A/C SYSTEM CONTROL AND REGULATION COMPONENTS
• A/C CONTROL HEAD -E87-, REMOVING AND INSTALLING
• COMPONENTS IN ENGINE COMPARTMENT AND REAR OF VEHICLE
• MULTIPORT FUEL INJECTION (MFI), GENERIC SCAN TOOL - 3.0L AVK
• MULTIPORT FUEL INJECTION (MFI) -1.8L 5V TURBO, AMB
• VEHICLES WITH 8 CYL. ENGINE (COMPRESSOR DRIVE VIA A SHAFT)
• COMPONENT OVERVIEW
• INSTRUMENT CLUSTER
• INSTRUMENT CLUSTER
• GLOVE COMPARTMENT, REMOVING AND INSTALLING
• SEATS FRAMES - EXCEPT CABRIOLET
• SEATS FRAMES - CABRIOLET
• DUST AND POLLEN FILTER ELEMENT, REMOVING AND INSTALLING
• DUST AND POLLEN FILTER WITH ACTIVE-CARBON-FILTER ELEMENT
• DIAGNOSTIC TROUBLE CODE (DTC) TABLE
• READ MEASURING VALUE BLOCK (FUNCTION 08)
• OUTPUT DIAGNOSTIC TEST MODE (DTM) (FUNCTION 03)
• CONTROL MODULE IDENTIFICATION (E.G. IN DISPLAY FIELD -2-)
• A/C CONTROL HEAD -E87-, CODING (FUNCTION 07)
• ADAPTATION OF VEHICLE IDENTIFICATION NUMBER (VIN), PERFORMING (ADAPTATION CHANNEL 81)
• DIAGNOSTIC TROUBLE CODE (DTC) MEMORY, ERASING (FUNCTION 05)
• DISPLAY GROUP 081
• DIAGNOSTIC TROUBLE CODE (DTC) MEMORY, CHECKING (FUNCTION 02)
• WINDSHIELD DEFROSTER, FUNCTION
• DISPLAY GROUP 009
• PRESSURE SIGNAL FROM HIGH PRESSURE SENSOR -G65
• A/C COMPRESSOR REGULATOR VALVE -N280- AND HIGH PRESSURE SENSOR -G65
• ADAPTATION OF FRESH AIR BLOWER RPM DECREASE, PERFORMING (ADAPTATION CHANNEL 08)
• DISPLAY GROUP 017
• OVERVIEW OF DESIGNATED ADAPTATION CHANNELS
• DISPLAY GROUP 125
• SOCKET ASSIGNMENT FOR VAG 1598 A TEST BOX WITH ADAPTER LEAD VAG 1598/11
• DISPLAY GROUP 014
• SAFETY PRECAUTIONS