mcs

Hi all,

I have a 2004 4.2 Sport with Sports air.

I believe it has been lowered with coding by the previous owner, going from some forum questions,

Today, I noticed the car took a while to get in lift mode. Then when I got home, I noticed that the left side of the car would drop around 10mm and pump up then drop and pump up all the time.

In Comfort/auto/dynamic the ride height is constant. The compressor isn't noisy, and there are no warning lights.

Very occasionally, the same side of the car that has issues, the headlight will stay pointed down. Could the level sensor be sending crap messages?

I have a scan cable coming but I am sure the suspension stayed constant in lift mode.

Thing is, it isn't a leak, the suspension hissing is controlled by the car. Thoughts?

Mike

03_AR_CO

scanning is certainly a good means of sorting out the real problem. As for the 1 corner you mention there may be a pinch/hole that is only exposed at a certain height, had similar issues with allroad airsprings, and there is really not much difference between allroad springs and the A8's springs. Get you VCDS cable and go from there is my advise though.

bmwm750

Concur. You need to get to the bottom of this quickly, otherwise you'll be buying more than just a new/ reman air spring/ strut assembly (i.e. new compressor, after all that duty cycling burns yours out).

mcs

I have done a scan of the car,

It says the G291 valve thing is faulty.

Is it expensive to replace and it should solve the problems? The compressor isn't noisy and the car struts don't seem to leek. The compressor is only really 30k miles old. Same with the relay.

Mike

2 Faults Found:
01487 - System Function Test
008 - Implausible Signal - Intermittent
Freeze Frame:
Fault Status: 00101000
Fault Priority: 2
Fault Frequency: 1
Reset counter: 120
Mileage: 175045 km
Time Indication: 0
Date: 2014.05.17
Time: 09:27:55

01772 - Signal from Level Control Pressure Sensor (G291)
008 - Implausible Signal - Intermittent
Freeze Frame:
Fault Status: 00101000
Fault Priority: 3
Fault Frequency: 11
Reset counter: 146
Mileage: 175399 km
Time Indication: 0
Date: 2014.05.22
Time: 17:25:37

ltooz_a6_a8_q7

I have no idea how to tackle these problems even if they exist in my scan. BTW, which module do you scan to get this? Autoscan?

Cheers,

Louis

dvs_dave

Pressure sensor is integrated into the valve block so not replaceable without changing the valve block. All that kit is located behind the front left wheel arch liner. First thing to try is cleaning up the electrical connectors on it as they may be the cause. If that doesn't work then a new valve block is needed. $250 plus fitting. Competent DIYer job. Just make sure you have car on axle stands/lift otherwise it will hit the deck when you disconnect the airlines and you'll struggle to get a jack back under it.

03_AR_CO

Here is my scan from address 34 before replacing the air compressor, not the valve body:

Address 34: Level Control Labels: 4E0-910-553.lbl
Part No SW: 4E0 910 553 H HW: 4E0 907 553 F
Component: LUFTFDR.-CDC H06 4480
Coding: 0015510
Shop #: WSC 20213 444 84343
VCID: 28541CFE9BAED75EFC3-807D

1 Fault Found:
01772 - Signal from Level Control Pressure Sensor (G291)
008 - Implausible Signal - Intermittent
Freeze Frame:
Fault Status: 00101000
Fault Priority: 3
Fault Frequency: 1
Reset counter: 217
Mileage: 86342 km
Time Indication: 0
Date: 2013.12.22
Time: 10:29:03


My experience with the G291 code is representative of pump in a weakened state.

mcs

The car wont lift at all anymore. But still no suspension light. It doesn't seem to be excessively low, but I noticed the compressor was on while the car was stopped. I haven't noticed that before.

Does the compressor wear out? Or do they always die as a result of the leak. The car has done just over 100k miles now. but the compressor was replaced in 2011.

I don't think the car has leaking struts as the car holds its level fine it just couldn't get to lift mode.

Mike

mcs

All the research I am doing seems to indicate a faulty compressor. Since it is making a noticeable noise (though not a deathly noise) I am going to rebuild it with a new piston ring and seal and see how I go.

If this cures it, then I win, as it costs like $30 AUD. A new compressor here is around $2k so I am happy to simply give it a go.

Mike

ltooz_a6_a8_q7

Please take pictures and shoot a video if you can please, it will be a great help.

Cheers,

Louis