AudiHarley

Air suspension compressor is not functioning. All VAGCOM gives me is "Note: Excessive Comm Errors" on the Level Control. It is a Continental Kompressor and as far as I know, it is original on the 2004 4.2, with 75K miles. It went out while I was driving when I went to raise the suspension from 2 to 3 on a wet day. Ride height warning light flashes for a while then goes solid. Does go off when the ignition is off. Level 1 light flashes constantly while ignition is on. No previous symptoms of problems prior to this; no dropping down while parked, no sagging on either end, no excessive compressor running. Is there a way to check to see if it is indeed receiving current and/or if the compressor will run via a different source? Any thoughts on this is greatly appreciated. One of these days I will have fixed enough stuff to be more of a contributor, than one asking for help. But hey, in the last eight months of owning this allroad I have replaced coil packs, replaced the fuel filter (with a hacksaw because of the rusted nut) and a few other interesting things with the help of all of you. Thanks again!

thejulex

From the sounds of it you have a failed controller not the compressor. The controller lives in the trunk area, on the left side just behind the lining but it is a pita to get to.

allroad55

It sounds like just a compressor fail which was my main headache in past.
My compressor was always bad condition especially on wet days.
Did you already tried lubricant and greecing to compressor?
Mine is fully recovered now!
Please refer to below.

https://www.audiworld.com/forums/sho....php?t=2790612

https://www.audiworld.com/forums/sho....php?t=2752617

But my concern is your VAG-COM code "Note: Excessive Comm Errors" this one i never saw it.
You may know well it should be controller or compressor or valve or somthing...because the machine is very next to you.
If you suspect on compressor or valve, try lubricant.
Thanks.

s4master1

Before anything reset the faults in the controller
from time to time the compressor overheats and the controller shuts it off until reset
after this see what fault or faults come back

AudiHarley

Thanks guys! I am going to unplug the compressor and hook it up to an external battery and see if it fires up. If not, then I'll take it off, lubricate, and give it another try. I did clear all the fault codes after the initial VAGCOM, but that didn't produce any new results. If it is the computer, not the compressor, any thoughts on where it is located and difficulty in replacing? Thanks again for all your help!

AudiHarley

Just re-read posts and the controller is in the trunk on the left hand side. Is it to the right of the navigation unit that sits above the pressure tank? Thanks!

AudiHarley

First, I tried unplugging the compressor and getting it to go on an alternate power supply while still mounted on the car; no luck. So then I took it off the car and wired it into a 12v battery and it came to life. So I mounted it back on the allroad, drove the car off the ramps, and lo and behold, the compressor kicks in and raises the car to level 1. So I punched level 2 then 3 and it complies. No more warning indicator on the dash and it is holding air so far. Not wanting to declare victory just yet, I ran a few Vagcom scans and this is what I got from the first one:
Address 17: Instruments Labels: 4B0-920-xxx-17.lbl
Part No: 4B0 920 981 P
Component: KOMBI+WEGFAHRS. VDO D12
Coding: 06283
Shop #: WSC 02407
VCID: 336BEB862B5D
WA1YL64B14N004747 AUZ7Z0C2423555

1 Fault Found:
01177 - Engine Control Unit
49-00 - No Communications

-------------------------------------------------------------------------------
Address 34: Level Control Labels: 4Z7-907-553.lbl
Part No: 4Z7 907 553 F
Component: - 2C1A1 D060
Coding: 25500
Shop #: WSC 09999
VCID: 4891AC6A42DB

4 Faults Found:
01397 - Venting Solenoid for Level Control (N111)
31-10 - Open or Short to Ground - Intermittent
01400 - Suspension Level Control
11-10 - Control Limit Not Reached - Intermittent
01772 - Signal from Level Control Pressure Sensor (G291)
27-10 - Implausible Signal - Intermittent
01770 - Temperature Sensor for Level Control Pump/Compressor (G290)
30-10 - Open or Short to Plus - Intermittent

The second run on Vagcom just gave me:
Address 17: Instruments Labels: 4B0-920-xxx-17.lbl
Part No: 4B0 920 981 P
Component: KOMBI+WEGFAHRS. VDO D12
Coding: 06283
Shop #: WSC 02407
VCID: 336BEB862B5D
WA1YL64B14N004747 AUZ7Z0C2423555

1 Fault Found:
01177 - Engine Control Unit
49-00 - No Communications

-------------------------------------------------------------------------------
Address 34: Level Control Labels:
VCID: 55AF751E8569
Note: Excessive Comm Errors

Then I cleared all DTC's and it gave me this:
Address 17: Instruments Labels: 4B0-920-xxx-17.lbl
Part No: 4B0 920 981 P
Component: KOMBI+WEGFAHRS. VDO D12
Coding: 06283
Shop #: WSC 02407
VCID: 336BEB862B5D
WA1YL64B14N004747 AUZ7Z0C2423555

No fault code found.

-------------------------------------------------------------------------------
Address 34: Level Control Labels:
VCID: 55AF751E8569
Note: Excessive Comm Errors

Any thoughts on where to go from here? Haven't driven the car around, but I have a feeling that if I do, it will probably drop down again. Thanks in advance for any advice.

s4master1

You could've done all this with the vag com
now see what is the pressure generated by the compressor it reads in bar, see if the car drops when you leave for a while, is possible the compressor is trying to keep up with an air leak and overheats, when this happens the control unit shuts it off and sometime won't come back until reset with a vag com

Tomihka

Hi... Im not one of a mechanic but I wanted to let you know that when my system failed, I bought a replacement and a lifetime fix. I got a conversion kit from Strutmasters. I love it!! I couldnt afford to fix it at the shop for the price they were quoting me for the parts so I did some searching on my own and decided to give it a try. I am so glad I did.. Check them out.