Since months, I am fighting a bunch of HVAC codes (typically 3 or 4 different
ones), tried meanwhile 3 different modules.

I am posting example recent scans of two different HVAC modules below.

Does the HVAC module need coding? If so, what is the correct one for my car? My car is a 1996 B5 A4 AFC 2.8 12V automatic.

If coding is not the issue: which components could be faulty and where are they located?


--------------

Repeat after clear codes, close vagcom, ignition off. Pressure switch still
shorted

Monday,16,May,2011,16:17:16:22662
VCDS Version: Release 10.6.4

Address 08: Auto HVAC Labels: 8L0-820-043-2D.lbl
Control Module Part Number: 8L0 820 043 B
Component and/or Version: A4 KLIMAVOLLAUTOMAT_D73
Software Coding: 04142
Work Shop Code: WSC 06335
VCID: 27530F41EF7D
3 Faults Found:

01297 - Sensor for Vent Temperature; Footwell (G192)
30-00 - Open or Short to Plus
01296 - Sensor for Vent Temperature; Center (G191)
30-00 - Open or Short to Plus
01206 - Signal for Duration of Ignition Off Time
27-10 - Implausible Signal - Intermittent

----------------

Codes after clear and pressure switch shorted with office clip:

Monday,16,May,2011,16:14:28:22662
VCDS Version: Release 10.6.4

Address 08: Auto HVAC Labels: 8L0-820-043-2D.lbl
Control Module Part Number: 8L0 820 043 B
Component and/or Version: A4 KLIMAVOLLAUTOMAT_D73
Software Coding: 04142
Work Shop Code: WSC 06335
VCID: 27530F41EF7D
4 Faults Found:

00792 - A/C Pressure Switch (F129)
31-00 - Open or Short to Ground
01297 - Sensor for Vent Temperature; Footwell (G192)
30-00 - Open or Short to Plus
01296 - Sensor for Vent Temperature; Center (G191)
30-00 - Open or Short to Plus
01206 - Signal for Duration of Ignition Off Time
27-10 - Implausible Signal - Intermittent

--------------

Codes after clear and new module, pressure switch connected:

Monday,16,May,2011,16:05:08:22662
VCDS Version: Release 10.6.4

Address 08: Auto HVAC Labels: 8L0-820-043-2D.lbl
Control Module Part Number: 8L0 820 043 B
Component and/or Version: A4 KLIMAVOLLAUTOMAT_D73
Software Coding: 04142
Work Shop Code: WSC 06335
VCID: 27530F41EF7D
3 Faults Found:

00792 - A/C Pressure Switch (F129)
31-00 - Open or Short to Ground
01297 - Sensor for Vent Temperature; Footwell (G192)
30-00 - Open or Short to Plus
01296 - Sensor for Vent Temperature; Center (G191)
30-00 - Open or Short to Plus

--------------------------

After erase, with AC pressure switch disconnected:

Monday,16,May,2011,15:56:20:22662
VCDS Version: Release 10.6.4

Address 08: Auto HVAC Labels: 8L0-820-043-2D.lbl
Control Module Part Number: 8L0 820 043 D
Component and/or Version: A4 KLIMAVOLLAUTOMAT_D75
Software Coding: 04162
Work Shop Code: WSC 06325
VCID: 29570979F969
4 Faults Found:

01297 - Sensor for Vent Temperature; Footwell (G192)
30-00 - Open or Short to Plus
01296 - Sensor for Vent Temperature; Center (G191)
30-00 - Open or Short to Plus
01206 - Signal for Duration of Ignition Off Time
27-10 - Implausible Signal - Intermittent
01582 - Signal for Coolant Temperature
30-00 - Open or Short to Plusq 1

--------

Monday,16,May,2011,15:51:44:22662
VCDS Version: Release 10.6.4

Address 08: Auto HVAC Labels: 8L0-820-043-2D.lbl
Control Module Part Number: 8L0 820 043 D
Component and/or Version: A4 KLIMAVOLLAUTOMAT_D75
Software Coding: 04162
Work Shop Code: WSC 06325
VCID: 29570979F969
7 Faults Found:

00785 - Temp Sensor in Instrument Panel (G56)
30-10 - Open or Short to Plus - Intermittent
00779 - Outside Air Temp Sensor (G17)
30-10 - Open or Short to Plus - Intermittent
00792 - A/C Pressure Switch (F129)
31-00 - Open or Short to Ground
01297 - Sensor for Vent Temperature; Footwell (G192)
30-00 - Open or Short to Plus
01296 - Sensor for Vent Temperature; Center (G191)
30-00 - Open or Short to Plus
01206 - Signal for Duration of Ignition Off Time
27-10 - Implausible Signal - Intermittent
01582 - Signal for Coolant Temperature
30-00 - Open or Short to Plus


-------------------------------------------------------------------------------
VCDS Version: Release 10.6.4
Data version: 20110418

Monday,16,May,2011,15:49:39:22662

Chassis Type: 8D - Audi A4 B5
Scan: 01 02 03 08 15 16 17 25 35 37 45 55 56 57 67 75 76 77



Address 08: Auto HVAC Labels: 8L0-820-043-2D.lbl
Part No: 8L0 820 043 D
Component: A4 KLIMAVOLLAUTOMAT_D75
Coding: 04162
Shop #: WSC 06325
VCID: 29570979F969

4 Faults Found:
00785 - Temp Sensor in Instrument Panel (G56)
30-10 - Open or Short to Plus - Intermittent
00779 - Outside Air Temp Sensor (G17)
30-10 - Open or Short to Plus - Intermittent
00792 - A/C Pressure Switch (F129)
31-00 - Open or Short to Ground
01297 - Sensor for Vent Temperature; Footwell (G192)
30-00 - Open or Short to Plus

 

Here is an older (original HVAC module) full scan. Module number and softcode.

VCDS Version: Release 10.6.3
Data version: 20101206

Wednesday,02,February,2011,17:23:29:22662

Chassis Type: 8D - Audi A4 B5
Scan: 01 02 03 08 15 16 17 25 35 37 45 55 56 57 67 75 76 77

Mileage: 212380km/131966miles
-------------------------------------------------------------------------------
Address 01: Engine Labels: None
Part No: 8D0 906 266 B
Component: 2,8l V6/2V MPI OBD2 D01
Coding: 01251
Shop #: WSC 06325
VCID: 2B5BF371F383

2 Faults Found:
16785 - EGR System: Insufficient Flow
P0401 - 93-00 - Unknown Error Elaboration
16540 - Oxygen (Lambda) Sensor B2 S2: Malfunction in Circuit
P0156 - 92-00 - Unknown Error Elaboration
Readiness: N/A

-------------------------------------------------------------------------------
Address 02: Auto Trans Labels: 01V-927-156.lbl
Part No: 8D0 927 156 J
Component: AG5 01V 2.8l2V US D89
Coding: 00000
Shop #: WSC 00000
VCID: 3469E80D2EBD

1 Fault Found:
00526 - Brake Light Switch-F
27-00 - Implausible Signal

-------------------------------------------------------------------------------
Address 03: ABS Brakes Labels: 4D0-907-379-ABS.lbl
Part No: 4D0 907 379 J
Component: ABS/EDS BOSCH 5 7679
Shop #: BB 37679
VCID: 356FD50925C7

No fault code found.

-------------------------------------------------------------------------------
Address 08: Auto HVAC Labels: 8L0-820-043-2D.lbl
Part No: 8L0 820 043 D
Component: A4 KLIMAVOLLAUTOMAT_D75
Coding: 04162
Shop #: WSC 06325
VCID: 29570979F97F

4 Faults Found:
01297 - Sensor for Vent Temperature; Footwell (G192)
30-00 - Open or Short to Plus
01296 - Sensor for Vent Temperature; Center (G191)
30-00 - Open or Short to Plus
01206 - Signal for Duration of Ignition Off Time
27-10 - Implausible Signal - Intermittent
01582 - Signal for Coolant Temperature
30-00 - Open or Short to Plus

-------------------------------------------------------------------------------
Address 15: Airbags Labels: 8A0-959-655.lbl
Part No: 8A0 959 655 D
Component: Airbag V AUDI D00
Coding: 00127
Shop #: WSC 06334
VCID: 3469E80D2EBD

4 Faults Found:
65535 - Internal Control Module Memory Error
00-10 - - - Intermittent
00532 - Supply Voltage B+
07-10 - Signal too Low - Intermittent
00588 - Airbag Igniter; Driver Side (N95)
32-10 - Resistance too High - Intermittent
01025 - Trigger for On Board Diagnostic Lamp; Malfunction
31-10 - Open or Short to Ground - Intermittent

-------------------------------------------------------------------------------
Address 17: Instruments Labels: 8D0-919-0xx-17.lbl
Part No: 8D0 919 035 G
Component: B5-KOMBIINSTRUMENT D08
Coding: 00262
Shop #: WSC 02032
VCID: 2E5DFA65C091

No fault code found.

End ---------------------------------------------------------------------

 

This is the oldest scan I have.

These 4 codes seem to return no matter what module is used:

01297 - Sensor for Vent Temperature; Footwell (G192)
30-00 - Open or Short to Plus
01296 - Sensor for Vent Temperature; Center (G191)
30-00 - Open or Short to Plus
01206 - Signal for Duration of Ignition Off Time
27-10 - Implausible Signal - Intermittent
01582 - Signal for Coolant Temperature
30-00 - Open or Short to Plus



VCDS Version: Release 10.6.1
Data version: 20100831

Tuesday,23,November,2010,10:57:19:22662

Chassis Type: 8D - Audi A4 B5
Scan: 01 02 03 08 15 16 17 25 35 37 45 55 56 57 67 75 76 77

Mileage: 211470km/131401miles
-------------------------------------------------------------------------------
Address 01: Engine Labels: None
Part No: 8D0 906 266 B
Component: 2,8l V6/2V MPI OBD2 D01
Coding: 01251
Shop #: WSC 06325
VCID: 2B5BF371F377

No fault code found.
Readiness: N/A

-------------------------------------------------------------------------------
Address 02: Auto Trans Labels: 01V-927-156.lbl
Part No: 8D0 927 156 J
Component: AG5 01V 2.8l2V US D89
Coding: 00000
Shop #: WSC 00000
VCID: 3469E80D2E49

1 Fault Found:
00526 - Brake Light Switch-F
27-00 - Implausible Signal

-------------------------------------------------------------------------------
Address 03: ABS Brakes Labels: 4D0-907-379-ABS.lbl
Part No: 4D0 907 379 J
Component: ABS/EDS BOSCH 5 7679
Shop #: BB 37679
VCID: 356FD5092533

No fault code found.

-------------------------------------------------------------------------------
Address 08: Auto HVAC Labels: 8L0-820-043-2D.lbl
Part No: 8L0 820 043 D
Component: A4 KLIMAVOLLAUTOMAT_D75
Coding: 04162
Shop #: WSC 06325
VCID: 29570979F98B

4 Faults Found:
01297 - Sensor for Vent Temperature; Footwell (G192)
30-00 - Open or Short to Plus
01296 - Sensor for Vent Temperature; Center (G191)
30-00 - Open or Short to Plus
01206 - Signal for Duration of Ignition Off Time
27-10 - Implausible Signal - Intermittent
01582 - Signal for Coolant Temperature
30-00 - Open or Short to Plus

-------------------------------------------------------------------------------
Address 15: Airbags Labels: 8A0-959-655.lbl
Part No: 8A0 959 655 D
Component: Airbag V AUDI D00
Coding: 00127
Shop #: WSC 06334
VCID: 3469E80D2E49

4 Faults Found:
65535 - Internal Control Module Memory Error
00-10 - - - Intermittent
00532 - Supply Voltage B+
07-10 - Signal too Low - Intermittent
00588 - Airbag Igniter; Driver Side (N95)
32-10 - Resistance too High - Intermittent
01025 - Trigger for On Board Diagnostic Lamp; Malfunction
31-10 - Open or Short to Ground - Intermittent

-------------------------------------------------------------------------------
Address 17: Instruments Labels: 8D0-919-0xx-17.lbl
Part No: 8D0 919 035 G
Component: B5-KOMBIINSTRUMENT D08
Coding: 00262
Shop #: WSC 02032
VCID: 2E5DFA65C065

No fault code found.

End ---------------------------------------------------------------------

 

With that many seemingly unrelated codes I would look over the harness and see if there are any broken/shorting wires.

 

2 codes seem always present:
01296: Sensor for Vent Temperature; Footwell (G192) - 30-00 - Open or Short to Plus
01297: Sensor for Vent Temperature; Center (G191) - 30-00 - Open or Short to Plus

I want to find the harness were those sensors are in. Yet the Bentley diagram does NOT show G192/G191 sensor. Where is it?

Bentley diagram:

 

Digging further into wiring diagram, Bentley electrical testing, etc:
a) looking at the wiring diagram for m.y. 1996, it does NOT list/show a G191 or G192 (Footwell Vent Temp Sensor). m.y. 1997 DOES.
b) electrical testing does NOT show test values for G191/G192. m.y. 1997 DOES.
c) the originally installed module was part number 8L0 820 043 D (label date 05/98) coded 04162.

Could it be that wrong module was installed, that is trying to look for sensor input that does not exist (open or short to ground error for G191 and G192)

None of the 3 modules I have can be coded to 00162, which would be the code for m.y. 1996.

 

the module with letter H seems to be entirely different looks, and impossible to find.
As an alternative, could I try to 'trick' the B or D module by adding the (in 1996 wiring diagram) missing G191 and G192 temp sensors and use one of the modules I have?

How can I find out
a) where those sensors are located (to get them possibly from a 1997 junkyard A4)?
b) Description and part number for those sensors?

 

I compared the wiring diagrams of the 97 with the 96 versions.
As suspected, the newer modules expect a voltage input from the 2 sensors (G191 Sender center outlet temp; G192 Sender floor outlet temp). They are on connector B5 and B6 on the module (nothing on those pin on the 96 module).
The resistance of those sensors should measuredeg C, 191 kohm, 192 kohm)

-10 - 47 - 16.2
0 - 29 - 9.4
10 - 18.6 - 5.66
20 - 12.2 - 3.5
30 - 8.2 - 2.23

Still needing the location of those 2 sensors (and how they look like so I can identify them when I see them) and part numbers.

I may try as a test to wire a 10k to B5 and 3k to B6, and splice into the brown/white 0.35 wire that goes is common to other on A67 connector (31 A/c in instrument panel wiring harness or T10p/7 (wire connector 10 point grey connector station left, A pillar).

This should feed a proper voltage into the AC module. See of it impacts those 2 related codes.

 

What?

 

Ignore it...subhuman spammer...reported and soon to be history.