A8 D3 Air Suspension Dramas, HELP!!!

[aji72]

Hi Guys,

I've got a problem. The suspension has gone into 'safe' mode (low and rock hard with the amber light on).

So far I've checked:
Compressor - OK
Relay - OK
Fuse - OK
Front height sensors - OK
Right rear height sensor - No ground and only measures ~3v on the supply line..? I'll check the left rear in a minute, but I've got a feeling either a plug is loose or one of the control modules has a problem. Does anyone know where the control module(s) is located?

 

[Alister]

Are you able to hook the car up to diagnostics to see what the fault code is?

 

[aji72]

Are you able to hook the car up to diagnostics to see what the fault code is?

I can't read the code, 'can't communicate with module' or something like that, but I have a feeling the problem is the right rear level sensor. Is the control module under the driver's seat? I wiggled a few wires under there and got a ground again and +5v on the supply line, but nothing on the signal line...

 

[aji72]

@Alister, just our of interest, what is the best scanner to buy for an A8 in your opinion. I've gotten away with a $30 ebay scanner for Engine, ABS, A/T, and Airbag for years, and I run VCDS lite with a 327 chipped USB cable for more in-depth stuff, but the A8 is very picky and often won't talk to VCDS lite. I know, you get what you pay for...

 

[jnrdavo]

full vcds/cagcom cable seems to be the best way to go... $400 or so if you can find them, and worth every penny in my mind... (no subscription either!)

 

[Alister]

I have a genuine Ross-Tech HEX+CAN USB cable. IMO this is the best option for a D3 A8.

 

[27litres]

I have a genuine Ross-Tech HEX+CAN USB cable. IMO this is the best option for a D3 A8.

+1 ^

OBD eleven is getting some good reviews too and has a functionality set to rival VCDS.

VCDS is the established player in the VAG world though, to the point that a lot of VAG independant shops use it.

 

[IchBautAuto]

I have a genuine Ross-Tech HEX+CAN USB cable. IMO this is the best option for a D3 A8.

Plus 1. I did get an email advising that the software wasn't going to be updated further than ver 17 as the USB was being superseded but I downloaded ver 18 the other day following Ross Tech links for the Hex + CAN USB.

 

[aji72]

Okay, I took a punt and went OBDeleven. It arrived today and I have to say it's pretty easy to use!

The report is:
------------
34 Ride Control System

System description: LUFTFDR.-CDC H05
Software number: 4E0910553E
Software version: 4290
Hardware number: 4E0907553E
Coding: 0015510

Trouble codes:
00668 - Vehicle voltage terminal 30 Open circuit/short circuit to ground
static
----
So, the system isn't getting power. Weird, because I've checked the fuse and relay and they both work. It's gotta be a connector. Does anyone know where the control module is located? Under the drivers seat perhaps????

 

[mcs_xi]

Okay, I took a punt and went OBDeleven. It arrived today and I have to say it's pretty easy to use!

The report is:
------------
34 Ride Control System

System description: LUFTFDR.-CDC H05
Software number: 4E0910553E
Software version: 4290
Hardware number: 4E0907553E
Coding: 0015510

Trouble codes:
00668 - Vehicle voltage terminal 30 Open circuit/short circuit to ground
static
----
So, the system isn't getting power. Weird, because I've checked the fuse and relay and they both work. It's gotta be a connector. Does anyone know where the control module is located? Under the drivers seat perhaps????

From memory the suspension ECU is located on the firewall behind the glovebox. There is a large relay under the carpet that seems to fail that runs the compressor which could also be the issue. I would jump onto A8 Parts Forum and have a look at the various tech manuals they have there. I found it worth downloading them all.

Mike