Just heard from the techs, they say it's that sensor control block. He's going to let me see if I can find a better price on it than what he can get from Audi.

+++

Waited a week to get the control valve in the mail, and it doesn't seem to have solved the problem.

They installed the new control valve, and "some of the codes are gone" but it "still doesn't know to send air to the 4 corners".

So they are trying to track down any broken wires between the valve and the control module, if they don't find any then I guess we replace the control module?

Does it sound like these guys know what they are doing?

I've read how some parts need to be somehow "configured" with the car's computer, is this one of them; and did they miss that step?

I've asked them to send me the codes so I can post them here.

what do you think?

-D:(

01575 - Controller switched off
 

After replacing the control valve, and finding no leaks, they have contacted me saying they have only one trouble code - and of course the car won;t lift a millimeter.

01575 - Controller Switched off.

But they don't know what to do. The service manager actually offered to pay for transporting it to the Audi dealer :(

I told him I would check the internet ;) I'm about to go do some searching, but wanted to post it here first. Has anyone seen this code, fixed it?

thanks!
-David

The question is what and why have switched it off.

It is a long shot but if the car has not been used for a while battery might be getting flat and power control switched some systems including suspension controller off to conserve energy. You can try running engine for a while to let the battery charge up or charge it off the car and then tell the car you have put new one in.

Might also check fuses and wiring connections.

Other then that I am out of ideas.

relearn the steering angle sensor?
 

I got this advice from an online source:
" I have seen that the battery went dead so the abs light / trac control light and the suspension light would be on and disabled. in order the suspension to reactivate the car must be driven in a straight line for at least 100 feet to relearn the steering angle sensor . once that has relearned the trac light would go off and the suspension light would go off. then the suspension would be active again. I do realize that the suspension in the front is low. the electrics battery MUST be fully charged or new battery is needed. This battery is a special AGM battery and the same must be used if replaced.
please try the test drive 100 feet until the lights turn off in the dash and then clear the suspension fault and then see if the air will go to the front struts"
also this:
"if the battery in the trunk is not charged correctly the battery will cook and render no good. if the battery is 2yrs old and older chances are that the battery will not take a full charge with the proper charger. that battery is a Glass Mat battery and can not take charging voltage over 14.3 volts."

Hoping someone can help,it's a longshot. Even the dealership seems to be at a a loss.

The compressor runs. eventually the green and yellow lights start to flash. Error code 01575 - Controller Switched off is thrown.

The shop I took it to claims to have tried the adaptation procedure and got no response from the car.

The dealership has done nothing yet but read the codes, and listen to the compressor run. When tehy learned that I replaced the compressor myself they immediately suggested that we put a new compressor on.

I asked them if a bad compressor was a known cause of 01575, and it is not. In fact they have never seen a car with that error. So it seems to me that they don't have any idea what is wrong, and are just going to throw parts at it until they get a clue.

Shouldn't the Audi Service department have access to more experienced technicians, some kind of hotline they can call for assistance when they don't have a clue?

Is there a way to determine if the compressor is good or bad?

thanks
-David

I'm fortunate enough to have not had any suspension faults with any of my d3's, buti have looked into it in the past.

The system is really very simple in operation. The compressor fills the tank in the boot, the tank in the boot supplies the control block, and the control block takes the high pressure line from the tank and directs the pressure to each of the 4 shocks as required.

If nothing will pump up at all, suspect pump or tank. If only one corner is looking bad, maybe a single shock is failing (although straining to lift a leaky shock may drain the rest of the system) and if anything else is wrong I guess it's the control block or wiring and wiring doesn't usually break itself.

Even if all the air is lost, it should sit on the bump stops and be bloody bumpy, but driveabe on flat road if required.

The only weird experience I have of air suspension going wrong was when a garage fitted new brake pads, but didn't put the suspension in jacking mode first. This causes it to stress itself out trying to level the car that is being jacked up at one corner.

When they had finished with it, it was totally deflated, with orange and green warning suspension lights on. I knew all they did was change the pads,so I drove it away figuring it would sort itself out, and it did. Took a good 15 mins, several miles etc, but it eventually seemed to recalibrate itself, fills the air tank and pumped up and levelled out. No bother with it ever again.

If it can drive, I'd be really tempted to drive it round for a bit and see what happens. Even a normal a8 will look unhappy after being sat a while. Even if you get a different fault code, it might tell something useful....

a later update
 

So, eventually I found a shop that had a clue, and was not just trying to rip me off.

They identified a leak in the front right strut, we replaced it, and the used compressor I bought was weak, but not totally failed. Being out of money at this point, I was driving the car but it would occasionally not get to ride height.

The towing company had damaged the front end, and they refused to accept an insurance claim, but gave me the run-around for an embarassingly long time. My plan was to get the nose repaired and trade the car in before the compressor failed altogether.

But that didn't happen. We had couple of days below freezing and the suspension failed again. Lights blinking, compressor times out and the car all the way down.

Here is what my mechanic tells me now:


That seems like a pretty thorough diagnosis. So who enjoys a difficult puzzle?

We did try that, not driving it but letting it sit, engine running. The compressor ran for just about a minute, then it shut off and the lights started to flash. We thought that it might, after a few minutes, run the compressor again, until teh tank was pressurized. But it never ran the compressor again, I sat there next to it for 23 minutes, and it never came back on.