BS_Smith

Intro

Have been reading AW and contemplating A8L purchase for at least five years. Increasingly felt the time to move on a D3 was near, before all too worn and available only "buy here; pay here." So, a couple weeks ago bought an '07 (Northern Blue/Amaretto, Prem Pack, B&O, Lifetime Sirius, AMI) w/ 84k from the first owner. Pretty car, nicely kept. $13k. Long time VAGer, w/ a vw convert bought new in '79. Had a ten year love/hate relationship with an '85 5000s non-q, non-t, 5 spd. The hate portion kept Audis away until an '00 A6 2.8q manual in '08, still my "real" car and a peach, now w/ 80k. Wife has a hatch A3. (Also a low mileage '03 Z06 and too many motorcycles in the garage.) In essence, the A8's role will be a bells & whistles amusement park ride, with some over the road work. Long time retired; nothing is "daily driver."

Thanks

As usually is the case with one forum or another--but not so often acknowledged--there are a few folks that are the backbone and intellectual capital of the group. For the most part, they came early and stayed late. Particularly impressive as price depreciation makes possible a much different owner pool than the new/CPO crowd. Many thanks!

Question 1: How to STFA?

Within the D3 Platform Discussion there currently are 479 pages dating back to 2004. Searching simply for threads with "suspension" using either Search this Forum or Advanced Search yields "Showing results 1 to 25 of 496" and "Page 1 of 20 1 2 3 11 > Last »". Clicking "Last" shows page 20, the earliest entry on which is from 03-02-2014. Haven't found anything to indicate search is limited to say 500 hits. So, Question 1: How to get more than 20 pages of search results?

Question 2: Suspension droop--how to proceed?

The suspension problem I'm searching for advice on is that the front end drops when the car sits, rather rapidly--two inches in 48 hours with the car in jack mode. Perhaps surprisingly the rate of drop seems the same on both sides. Nine months and two thousand miles ago the previous owner had the RF strut and a burnt relay replaced due to a reported "front is not going up" problem. Shop was independent but the strut was a $1200 part and presumably OE. No dash warnings. Question 2: How to proceed? A "throw parts at it" solution might say replace the LF with a new Arnott and see. But the equal drop seems to suggest it's not a failed strut. (Have VCDS; Bentley on the way.)

Thanks, again.

dvs_dave

Only advice I can give on the AW search function is don't bother. Use google search instead and follow any search terms with site:audiworld.com to keep it AW specific.

Regards your specific suspension problem, what error codes is VCDS giving? Difficult to give any specific advice without that info.

mishar

Welcome to the board!

It would be even nicer to have you if you use some of that long retired time to type few words instead of abbreviations.

Regarding search Dave said it all.

Front drop is most likely one of struts. It always goes down both sides but one is going faster. You have to follow it closely in order to find which one. VCDS scan always comes first. In the meantime put it in Jacking mode and lift one front side at the time. If you hear air venting that's your culprit. If not try soapy water test.

BS_Smith

Thanks for the responses. I'm particularly interested also in the related thread begun today by larora.

Here's further info regarding my suspension problem, with a couple questions at end.

I've been tracking the rate of front end drop over the past few days; see attached Drop Data.

Measurements were made at about the same time of day and taken from floor to wheel arch at the hub center. Both sides have dropped about three inches over four days, the left about a half inch more than the right, with the left dropping at an increasing rate and the right a decreasing one. According to the '07 owner's manual, ground clearance with lift is 5.7" and 3.9" with dynamic; the car's front has dropped about an inch more than that range.

As mentioned earlier, the RF strut was replaced 9 mon/2k mi ago.

What I didn't mention earlier is that three months ago an indie service record from the previous owner indicates that the battery was replaced because of a reported "Air suspension fault and warning lights on. Air suspension is pancaked." The diagnosis was "All codes related to low battery voltage. Cleared codes and reset adaptations." A story similar to larora's certainly. But the battery replaced in my car reportedly was the original from '07, so regardless of cause, it was due.

In my case, it's clear one expensive suspension part and/or another needs replacement. I of course only want to determine, and minimize, which one(s).

Dave and mishar have asked for codes. I omitted them earlier, intending to send a fresh set taken after some road time subsequent to concluding the drop measurement. But those available now also may be of interest.

The set taken 29 Feb (attached) was done prior to code clear.

Under Address 34: Level Control, the faults, all intermittent, are:

• Implausible Signal from Level Control Pressure Sensor
• Suspension Level Control --Upper and Lower Limits Exceeded
• Turn-Off due to Over-Temp--Upper Limit Exceeded (This fault last occurred 21 Feb, while driving in the DC area, and before the 375 mi trip north a couple days later--may have dodged a bullet!)

The second attached log was made 1 Mar directly after doing a global code clear. I suspect it's not of much use for diagnostic purposes, but it has a couple puzzles for me. That is, why after the global code clear do some codes persist, with dates preceding the clear? For example, at address 42 an intermittent fault is reported for Control Module for Seat & Steering Column Memory--dated 2015.10.08. Why isn't this removed by the global clear?

And the larger question of course, "what to do next?" Although the rate of drop is relatively rapid, it's not fast enough to be noticed by continuous observation. I don't see where there's scope for watching which (if either) side falls first. Also I don't understand why if one strut has failed, the other side also will drop, with some delay. I assume the two sides are independent pneumatically, so that a leak on one side wouldn't cause the other to bleed down as well. And except for minor shift of fluids side-to-side, the weight supported by a strut shouldn't change just because a faulty strut on the other side isn't carrying its share as designed. Strut x isn't saying to y, "well, if you're not going to do your job, neither am I!" I note also the rear suspension seems unaffected by problems up front. What am I missing?

mishar, to be clear: you're suggesting raising the car by floor jack, one side then the other, and listening for an air leak, correct? (I'll get to leak detection via soapy water in due course, but at the moment it's still rather cold for concrete crawling for this fellow.)

A final question, in tedmur's case, how was the determination made that the problem was a faulty distribution block (and not a strut)?

Many thanks for any advice.

BS

dvs_dave

You're over thinking things. Left front strut is leaking. Fix leak/replace strut asap before you burn out the compressor also.

Tell tale is left side is dropping more than the right side. As the left side is no longer able to support weight, the right side has to take up the weight instead and sinks too, just not as much. Think of the 4 legs of a table. Couple this with the right strut being new, it's far more likely for the original left strut to now be the problem.

MP4.2+6.0

+1 Sort of hard to read, but I concluded pretty early it was left strut. As Misha said earlier, you have to look for subtle differences. The sway bar tying both sides of the suspension together plus the weight transfer as one "leg" gives out over to the good leg forces both sides down. Then just as picked up on this reply I'm piggybacking, the fact the right was already done puts the focus on left one anyway. Separately an absence of codes on the air block (typically a solenoid there) suggests it probably isn't that component either, which might also induce a front drop.

Net, all signs are pointing to left front and no signs to anything else. Not foolproof, but as much data as I had when I concluded (correctly) it was a specific one of my fronts as well. As Misha said, about all that is left might be jacking up left side and listening for air and/or soap testing it. I tried that on mine and could not hear anything nor got any soap bubbles. Mine went down a couple inches overnight and fully by second day.

For OP, welcome BTW. Likewise I had a 1985 Audi 5000S 5 speed. I took it to about 120K miles (from new, Euro delivery; ordered w/ no sunroof and the 5 speed). Family member took it past 200K. Tranny finally gave out when it got its last rites.

For search BTW, definitely use Google. Also try to think of ways to make it more specific--thus not just "suspension", but also what else is going on like a droop and maybe a leak. Use the alternative options too. Thus: "suspension (droop, drop, slam, fall, bottom) (leak, loss) D3 A8 site:audiworld.com". Just making that up, but t's an example of getting enough qualifiers in to tighten up search results some, but w/ enough variants to try to avoid missing valuable ones that any one word choice may accidentally knock out.

mishar

Yes. Lift the left side first. If you are lucky you will hear loud venting. That comes when damaged part of airbag is exposed. While leveled it is probably leaned to the inside metal tube and leaks slowly.

Check the attachment. It will provide a base for further evaluations.

P.S. Forgot to say: Dave and MP said it all.

BS_Smith

Suspension droop

The car now has a new LF strut from Arnott. Tables below demonstrate the improvement in suspension air retention. The first (also seen earlier in this thread) shows the unpleasant +3" front end drop over four days. The second table shows measurements taken after LF strut replacement. The side with the new strut now drops less than an inch over four days. Hurray! The RF, whose strut was replaced nine months ago, now drops about an inch more than the LF--but about an inch less than it did before the LF was replaced.

Before


After


So... So far, so good. But then, what about those dang codes? From today:

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 02313 785 00200
VCID: 285F965F9BB6BE7E16-807C

2 Faults Found:
01772 - Signal from Level Control Pressure Sensor (G291)
008 - Implausible Signal - Intermittent
Freeze Frame:
Fault Status: 00101000
Fault Priority: 3
Fault Frequency: 4
Reset counter: 158
Mileage: 136203 km
Time Indication: 0
Date: 2016.03.25
Time: 10:18:28

01575 - Control Switched Off
000 - -
Freeze Frame:
Fault Status: 11100000
Fault Priority: 4
Fault Frequency: 1
Reset counter: 118
Mileage: 136237 km

Here too there was improvement, but apparently only partial. After code clearing, the "01400 - Suspension Level Control" upper and lower limit exceptions have not returned, nor has the "01577 - Turn-Off due to Over-Temp". Good news of course--but the car has traveled little since strut replacement.

Unfortunately, the 01772 intermittent implausible signal from the level control pressure sensor is back. The Ross-Tech wiki for 01772 indicates possible causes are wiring issues, air leaks, a bad pressure sensor in the solenoid valve block or a bad adaptive air suspension control unit. It seems wiring issues likely would generate a different 01772 error message--short circuit to pos or to neg are given as alternative 01772 subsets in addition to the "implausible signal" reported by VCDS here. Air leaks also seem unlikely as the system now, more or less, holds air. Bad sensor? Bad control unit? Maybe.

The R-T wiki also says that for A8s, "check TSB 43-08-16 | TPI 2018765", which is available in Bentley. But it's titled "Self Leveling Compressor Inoperative" and the TSB concerns compressor (and relay) replacement. After concluding the second set of height measurements, I put the suspension in lift mode and verified that the system indeed is able to lift the car.

It seems VCDS may be able to test or interrogate the pressure sensor and/or control unit. (I need to do more reading.) It also seems that any damage to the compressor already has been done and if it worsens/fails, the solution will be to replace the compressor. I believe I've read that there are rebuild kits for the compressor, but at this point I'm not eager to go that route. One, it's not clear to me that the compressor is failing. Two, I assume rebuilding is the same whether the compressor is partially or completely failed. (Three, I'm a procrastinator.)

Oh, I also assume that the "01575 - Control Switched Off" is because the suspension was in jack mode when read.

Your thoughts are welcomed.

Bentley

I want to give a mild vote of support in favor of Bentley. On first inspection though I thought it a disaster--yet another example of a good company left to wither and die. Only runs under XP?! And the latest MS OS that the workaround documented by Bentley is for is Win 7--and that workaround doesn't work for Win 10?! So, I wrote Bentley, ostensibly to the company president (an option from their website's pull-down list), referenced the incompatibility between their product and MS's current OS, and said that I was ready to buy, were they ready to sell? The response (not from the company president...) also was not impressive; in essence, "there are solutions out on the web for running XP under Win 10." Nothing more specific or helpful.

But sure enough, there are solutions out there. So, I decided to buy a copy of the Bentley CD from Amazon for $101. The solution opted for is to run a virtual machine under Win 10 using Oracle's VirtualBox, and XP under that using MS software to test Internet Explorer on different OS's, and then Bentley's eBahn reader under XP. Whew! It's a bit of a head spinner but doable, all with free s/w.

Once installed, it works well enough, but there are frustrations. The XP emulator is only good for 30 days, and then needs to be renewed (but at least the large file doesn't need to be re-downloaded). Also, I've not figured out how to copy and paste from Win 10 into the virtual machine, so until realizing I could create a file within XP with the VIN to copy from, I had to key the VIN in each time I used the manual. And alt+tab gets into XP from Win 10, but not back the other way. Lastly, it seems possible to print to a physical printer within XP, but not to a pdf. Anyone remember if/how it's done?

Despite the inconveniences, it is possible to have a hold-in-your-hand version of the Bentley electronic manual, for a not large, onetime cost, without having to buy old s/w and an old pc to run it on. (There was no way I was going to pay any price for the same XP disks I threw out ten years ago.) Even better, purchase of the cd gives access to an online version of the manual as well, reportedly still in beta but seemingly well-developed. Whether true or not, I rationalize Bentley's failure to keep their cd manuals easily usable with current operating systems is because they intend to shift to an online only model in future.

This "straight-shooter" will close with--many thanks for past assistance!

--------------------------
2007 A8L 4.2

MP4.2+6.0

There is a lot in here! But let me simplify down to....I think you still have a leak! I edited your post down above (... = snip) to try to focus folks' eyes on what caught mine. Simply put, a nearly 2" drop three days later on the right side is unacceptable to me. Except for the one time mine lost a strut, I can leave for a vacation of one, two or even three+ weeks and my car always looks the same basically on return. Two inches would be painfully obvious, since that would eliminate most of the every day fender gap on mine, a non sport.

It seems like something is pretty clearly wrong involving the right front. In turn, it is likely pulling down the left front. That occurs with the weight transfer as the right front drops over to the left, as well as the levering of the sway bar. Now it is basically just the opposite of what you had the last go around where the left was gone and pulling down the right. A guess now in retrospect is your left was bad as expected, but your replaced right was itself also defective or failed again--it just leaked less than the old left one. But, also read further below about valve block questions before concluding this firmly.

Then in turn from what I read here, I would be looking at that right front yet again as a likely leak area (replaced or not), as well as the valve block. You have the other discussion about the codes as well that sounds like it overlaps to the valve block. Thus before replacing right strut (or rather submitting it to Arnott for a warranty claim), I would look hard at valve block. Leak test it for starters with soapy water. I also haven't looked at exactly how it functions, but a guess would be to see if it is permitting air to flow backwards or out after shut down. Leaving the four strut lines in place and then pulling what ever the "out" is to look for any errant air flow (soap bubbles) coming out of those connections would seem logical. Again, I haven't studied valve block, but am imagining it basically has "air in" from compressor and "air out" to vent air from lowering operations. Conceptually leak could either be venting on the "out" side when it shouldn't be, or failure of the relevant valve to seal on the "air in side" so air can run "backwards" out of strut toward compressor.

None of this is with certainty by any means. It's mostly just reading the info you provided and trying to provide an independent/fresh perspective. I guess I would do more diagnostics around air block, but if inconclusive AND you don't find any obvious leaks relating to RF strut you might take a chance and $400 (approx. dealer discounted price IIRC?) to replace valve block, esp. with some of the code suspicions. Otherwise you could end up pulling RF strut again and dealing with Arnott only to find something is still wrong. Air block is also comparatively easy to pull out.

P.S. Bentley: I think the reality is Bentley and Audi parted ways. If you go to their site, in about 5 seconds you can see they have no product for any current Audi. But given the IP braintrust at AoA, let me guess that they left Bentley with perpetual rights to sell license copies. Meantime, in Bentley world, no incentive to do anything other than clip license coupons basically. They may not even have a license to modify now (post go-forward termination), hence the marooned XP. Back at end of life on my prior A6, they did publish a paper version (a 2-3" old 'phone book' size) of most of what was on the same XP disk they sold for that one. My Mini S from 2010 even was covered in a hardcopy book they put out. But, it is what it is. Meanwhile, yep my head hurts from your explanation (good work, and A+ for effort). For me, it would be all of that in an environment on a Mac. So instead ...I just run it on my now college grad kid's XP small Sony lap top from like 12 years ago. Sunk cost, so it's now "free" and would otherwise have bee scrapped years ago like various others. All I have on it is Bentley and VCDS, plus Word to paste the scans into and the old Explorer browser just good enough to log in to gmail and e mail scans to myself/my Mac. Oh, I did spend 5 minutes on it last week for the first time since stripping applications and files down 5 years ago to to buy a new clone battery for like $18 off Amazon. I was down to about 30 minutes run time off the charger. Consider just asking family and friends if someone has an old XP laptop in a drawer somewhere. Or, eBay. A lot of XP machines never made the move to 7, and MS reported a large number were still running when they finally discontinued support, including in business functions.

BS_Smith

Thanks for the advice, MP. Not a cheerful prospect, but appreciated nonetheless.

Note the strut replaced earlier was done by the previous owner, so I've no warranty on it and therefore will be trying very hard to find something else as the source of trouble.

Will report back in event of any good or bad news.