# 2003 Audi Allroad AC Inoperable



## 97VWJett (May 17, 2003)

So the AC on my new to me Allroad does not work and it's warm outside!

I don't think it's working because the HVAC system thinks the cooling system is too hot and is cutting the ground circuit on the AC clutch.

I have done a full scan of the vehicle, but I don't have it with me right now. I will post it tomorrow. The one I remember for the Auto HVAC is:

01582 - Signal for Coolant Temperature 30-00 - Open or Short to Plus

I have checked the fuses, all are good. I have checked/swapped relays and they are good. I also ohm tested the relay pins, that checked out okay as well. I put power from pin 85 to pin 30 on the relay panel and the AC worked. I also swapped the pressure sensor below/behind the passenger side head light assembly just to be sure. I have checked the pressures on the AC system and it's correct.

I looked in AllData and it recommends that the wiring be checked between the Instrument Cluster and HVAC head unit and/or the signal that is generated/calculated from the Instrument Panel to the head unit. I understand this information is sent via the CAN-BUS system. 

I want to know if there are any connectors that could/would be disconnected that are dedicated to this circuit. What signal/measuring blocks can I look at in the Instrument Panel or HVAC system to figure out what the head unit is receiving?

I also understand that the instrument panel could also be the culprit. I also know the center of the display, at the top, is fading and the odometer is missing a few dashes on the second from the right character but that is the only issue I am aware of.

I did check the Instrument Panel for codes, no codes BTW.

What do you guys think?


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## 97VWJett (May 17, 2003)

Wednesday,10,August,2011,19:06:47:41510
VCDS Version: Release 10.6.4
Data version: 20110418
IPM Auto Service



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Chassis Type: 4B - Audi A6 C5
Scan: 01 02 03 06 08 15 16 17 18 22 34 35 36 37 45 55 56 57 65 67
75 76 77

VIN: WA1YD64B13N061607 
-------------------------------------------------------------------------------
Address 01: Engine Labels: 078-907-551-AZA.lbl
Part No: 4Z7 907 551 S
Component: 2.7L V6/5VT G 0020 
Coding: 07755
Shop #: WSC 05140 
VCID: 53AE883C8B65
WA1YD64B13N061607 AUZ7Z0B2257597

1 Fault Found:
18005 - Powertrain Databus: Missing Message from Level Control System (J197) 
P1597 - 35-00 - - 
Readiness: 0000 0000

-------------------------------------------------------------------------------
Address 02: Auto Trans Labels: 01V-927-156.lbl
Part No: 4Z7 927 156 M
Component: AG5 01V 2.7l5VT USA 2122 
Coding: 01002
Shop #: WSC 02325 
VCID: 50A48730BA73

1 Fault Found:
18265 - Load Signal: Error Message from ECU 
P1857 - 35-10 - - - Intermittent

-------------------------------------------------------------------------------
Address 03: ABS Brakes Labels: 8D0-907-389.lbl
Part No: 4Z7 907 389 A
Component: ABS/ESP allrad D56 
Coding: 06497
Shop #: WSC 02325 
VCID: 4A9095585C2F

1 Fault Found:
01310 - Level Control System Control Module (J197) 
49-00 - No Communications

-------------------------------------------------------------------------------
Address 08: Auto HVAC Labels: 4B0-820-043-MY1.lbl
Part No: 4B0 820 043 G
Component: A6-Klimavollautomat D55 
Coding: 00160
Shop #: WSC 02324 
VCID: 1E382908B027

1 Fault Found:
01582 - Signal for Coolant Temperature 
30-00 - Open or Short to Plus

-------------------------------------------------------------------------------
Address 15: Airbags Labels: 4B0-959-655-AI84.lbl
Part No: 4Z7 959 655 J
Component: Airbag 8.4EP 2000 
Coding: 0000607
Shop #: WSC 02325 785 00200
VCID: 56A871289897

No fault code found.

-------------------------------------------------------------------------------
Address 16: Steering wheel Labels: 4B0-907-487.lbl
Part No: 4B0 907 487 F
Component: Lenkradelektronik D01 
Coding: 01002
Shop #: WSC 02325 
VCID: 2F66E4CCC78D

No fault code found.

-------------------------------------------------------------------------------
Address 17: Instruments Labels: 4B0-920-xxx-17.lbl
Part No: 4B0 920 981 P
Component: KOMBI+WEGFAHRS. VDO D12 
Coding: 06264
Shop #: WSC 19411 
VCID: 336EE8BC2BA5
WA1YD64B13N061607 AUZ7Z0B2257597

No fault code found.

-------------------------------------------------------------------------------
Address 35: Centr. Locks Labels: 4B0-962-258.lbl
Part No: 4B0 962 258 M
Component: Central Lock/Alarm D37 
Coding: 15885
Shop #: WSC 23436 
VCID: 336EE8BC2BA5

No Faults Found
or DTCs not supported by controller
or a communication error occurred

-------------------------------------------------------------------------------
Address 36: Seat Mem. Drvr Labels: None
Part No: 4B0 959 760 B
Component: Sitzmemory R1 F 0102 
Coding: 00001
Shop #: WSC 00000 
VCID: 2C5CF3C0F69B

No fault code found.

-------------------------------------------------------------------------------
Address 56: Radio Labels: 8E0-035-1xx-56.lbl
Part No: 4B0 035 195 L
Component: symphony II NP2 0051 
Coding: 00205
Shop #: WSC 07322 
VCID: 29520AD4F969

No fault code found.

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


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## 97VWJett (May 17, 2003)

If I go into Measuring Blocks for the Auto HVAC (08) and then Group 11, the value in the first field is -40C hmmmmm!!


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## 97VWJett (May 17, 2003)

I have replaced the G62/Green coolant temperature sensor for the computer which is shared with the HVAC system. I am going to do a full clearing of all codes and see what happens.


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## 97VWJett (May 17, 2003)

Tried clearing codes and running Basic Settings, no change. Code is still present.


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## mwebb (Apr 19, 2008)

*two coolant temp sensors*

very often there are two coolant temp sensors , one is in the radiator hose , one in the plastic flange on rear of cylinder head 

measure values of the one you replaced 4 volts is cold .5 volts is hot , use T pins , do not puncture insulation


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## Dana @ Ross-Tech (Sep 15, 2009)

97VWJett said:


> Wednesday,10,August,2011,19:06:47:41510
> VCDS Version: Release 10.6.4
> Data version: 20110418
> IPM Auto Service
> ...



Hi,

The repair manual lists two possible causes of that fault in the A6:

* Short or open circuit between instrument cluster and A/C Control Head -E87
* Instrument cluster malfunctioning.

It goes on to make specific notes and the A6 and Allroad having quite a few possible modules with Gen 1 and Gen 2 HVAC systems. I didn't dig in there since this sounds like the HVAC module is original and we aren't going after compatibility issues.

Where is the Level Control module? If that module is installed and functional, the ECT communication to/from the cluster and lack of Level Control may be related. 

What are the ECT MVB readings in the Engine and Cluster? 
What are the MVB readings in the cluster for internal communication, which starts with group 125 and up?


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## mwebb (Apr 19, 2008)

*level control is address 34*


address 34 does not seem to be reporting on his network 
could be a fuse 

the control unit is under the left headlight very close to the belly pan 

the VW Phaetons do have 2 coolant temp sensors , similar systems , one is in the radiator hose , i would look very closely at the wiring diagrams for address 08 before chasing a possible network ghost that only involves one PID .
**********************************************************
Address 34: Level Control Labels: 4E0-910-553.lbl
Control Module Part Number: 4E0 910 553 E HW: 4E0 907 553 E
Component and/or Version: LUFTFDR.-CDC H05 4290
Software Coding: 0015510
Work Shop Code: WSC 02313 785 00200
VCID: 254A4E1990C4
2 Faults Found:

01583 - Leak in System Detected 
000 - - 
Freeze Frame:
Fault Status: 11100000
Fault Priority: 3
Fault Frequency: 1
Reset counter: 240
Mileage: 110279 km
Time Indication: 0
Date: 2011.06.09
Time: 08:24:59

01400 - Suspension Level Control 
002 - Lower Limit Exceeded - Intermittent
Freeze Frame:
Fault Status: 00100010
Fault Priority: 2
Fault Frequency: 3
Reset counter: 24
Mileage: 110275 km
Time Indication: 0
Date: 2011.06.08
Time: 15:24:10
on this one there was a poor connection at the pump , also near the belly pan under left headlight , the system thought / knew it had activated the pump , saw no change is ride height and incorrectly assumed the pump was operating and there was a leak in the system 
wrong .
VOLTAGE DROP was the cause ... as it usually is


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## 97VWJett (May 17, 2003)

The suspension was replaced with struts/springs prior to me purchasing it. I have not had a chance to check to see if it's unplugged or missing yet. The suspension lights are all off though.

I will get back to you guys ASAP. Thanks thus far!


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## [email protected] Parts (Nov 27, 2006)

What does outside ambient temp report in 17 cluster MFA or VCDS?

You want to verify the sensor in the front of the condenser at the bottom behind front bumper.


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## 97VWJett (May 17, 2003)

You are talking about the high pressure sensor?


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## [email protected] Parts (Nov 27, 2006)

Nope


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## teerak2uk (Sep 22, 2007)

No they are talking about the sensor mounted behind the front grill that measures outside temperature of which i have seen some showing a measurement of -40 and stops your ac working


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## 97VWJett (May 17, 2003)

But that is the ambient temperature sensor. How is that related to the coolant temperature sensor that is open or short? 

I did check to see if the Suspension Leveling Control Module was installed, it is not.


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## [email protected] Parts (Nov 27, 2006)

Well look at it this way.

If the coolant temp sensor had a DTC it would also be in the 17 and 01 ecu for a short to B+
( Most likely not always )

What is measuring blocks saying when looking at values for outside ambient Temp in cluster compared to climate control?

What does coolant temp report at ECU and cluster?

Use some thought's outside the box.

Maybe the code is labeled wrong.


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## 97VWJett (May 17, 2003)

I didn't have time to check with the VCDS but I did take another look at the CTS. I noticed "regular" electrical tape on the harness. I peeled it back. Someone but connected 4 VW repair wires to the harness! The butt connections *seem* to be okay. More digging to come. 

Also, why does the ECU have a cage on it around one of the connectors with those weird bolts that have to be cut off or removed with vice grips?


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## [email protected] Parts (Nov 27, 2006)

Cause they dont want you in there or the car gone in 60 seconds.


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## 97VWJett (May 17, 2003)

So more factoids to add:
Someone replaced the CTS connector and used 4 VW repair wires
Wiring between cluster and HVAC module is good
Removed both and did a visual inspection of PCBs - looked okay
MIL and Cruise lights are inoperable on instrument cluster. Some of the odometer characters work intermittently. Part of the middle display fades when hot.
The coolant fan does not work when I run the output test
Instrument panel coolant temp matches what the ECU sees
HVAC is still -40C
Tried replacing the thermal switch in the lower radiator hose - no change

I need to figure out why the coolant fan does not work. Maybe that will cure the AC?


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## 97VWJett (May 17, 2003)

Okay right fan works with 12v applied. Need to jump switch on lower radiator hose to see if module is okay or not.


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## 97VWJett (May 17, 2003)

Okay fan control module is inoperable. I jumped pins 1 and 2, no fans. Jumped pins 3 and 4, no fans. I am going go replace the module and check back.


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## 97VWJett (May 17, 2003)

3 year old update

Replacing the AC control unit fixed fans and AC. Got one from another allroad and it began working immediately


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## roy001 (Jun 24, 2010)

*Dead A/C*



97VWJett said:


> 3 year old update
> 
> Replacing the AC control unit fixed fans and AC. Got one from another allroad and it began working immediately


That was interresting. 
I have a 2001 Allroad and the A/C died now. 
evacuated and refilled the refrigerant
replaced the sensor on the radiator outside
A/C runs and creates low and high pressure if I add 12V to the yellow cable that's headed to the compressor
VCDS find NO error codes

What can it be? 
Malfunctioning relay?
AC control unit?


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## roy001 (Jun 24, 2010)

*Case solved*

I just wanted to drop by and tell that I have solved my case. 
It was the relay for the A/C clutch "267"
It's located in position no. 5 in the relay compartment under the steering wheel (left hand drive). 
You have to remove the cover under the steering wheel /above the pedals to get access to the relays. 
It looks like this:









Actually it's just an ordinairy "30-87" relay, så almost anything can replace it. 
I tested my relay with a multi meter and checked the resistance between terminal 85-86 which is the coil.
No contact. Testing another relay, and it's 50-80 Ohm. 

So, now the A/C is ok again, and everything else is tested too.


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## RichardSEL (Apr 5, 2010)

And we don't want your :bs: in here. 

Mr Gozer please delete the cretin... And perhaps the user a/c too?


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