njroute22

I did an acceleration sender unplug test today.

Unplugging both front acceleration senders

• All four struts had the same amperage readings. Between 0.45a and 0.8a. Surprisingly, the ride was not horrible.

Unplugging either the driver or passenger sides only

• Oddly, the front struts behaved exactly as if I had them both plugged in - between 0.1a and 2.04a.
• The rears fluctuated while driving, but never topped off past 1.5a. (It was normally 1.8a)
• The ride was actually pretty good.

I'm not sure what this test has determined really. I don't see anything screaming at me that I discovered something.

I suppose the test would be more complete if I had easier access to the rear acceleration sender.

Case: Still open.

dvs_dave

Whilst the accelerometers are unplugged, what does the output test current for the front struts look like?

njroute22

I mentioned that in the post before yours. Maybe my formatting made it easy to miss.
When I unplugged both fronts - the amperage were between 0.45a - 0.8a. For all four shock absorbers.

dvs_dave

Yes, but that was the live values whilst driving though, right? I meant what about when you run the VCDS output tests on the dampers? You know, hard current, soft current etc. What are the amperage values being displayed whilst running those tests with the accelerometers unplugged?

njroute22

Sorry I misunderstood. No, I did not run an output test on VCDS whilst the acceleration senders were unplugged. I thought that live values whilst driving would give me the information I needed to determine whether it was an issue I should be concerned with.

I have some more interesting updates coming soon. I may have stumbled upon something that has not been discussed whatsoever in this thread. Something so simple. I just need a few days to confirm.

dvs_dave

Ok. Unplugging the front accelerometers and it then seemingly riding ok, with the front damper currents equal to the rears suggests that the signals they’re providing may be influencing things for the worse. Are they the correct part numbers, are they correctly orientated, does swapping them around do anything? Are the readings they’re providing consistent with the rear, etc.

njroute22

When I said "okay," I sort of meant it wasn't as AWFUL as it has demonstrated in the past. In other words - the ride didn't go to total hell. Basically, it was not a major change.

From what I can tell - these are original acceleration senders/sensors.

(I have yet to swap them around, nor have I run a VCDS test with them unplugged.)

I did, however, order three replacement acceleration sensors - just to waste yet more of my money. I even bought a "YAW" sensor on eBay. The total cost for all four delivered was about $50. What the hell, why not? Need something for comparison.

But.... a big note here - and an update from one of my previous posts:
-------------------------------
Three days ago, I thought I stumbled upon a magic solution.

One thing no one has mentioned yet here in this thread - was to "reset to factory defaults" in the ride control module. I have not seen this documented anywhere (i.e., Ross-Tech, etc.) They just show how to re-calibrate the heights using adaptation modes 1-5.

If you "read" channel "00," it lets you reset to factory defaults. I tried that, as well as re-calibrated afterward. Lo behold, the car rode PERFECTLY.

For about a day and a half.

The ride in the car slowly and noticeably got worse OVER TIME.

This leads me to believe that maybe it IS the acceleration sensors to some degree.

Take a look at this screenshot of the famous Audi document... pay attention to the highlighted text. Notice how it says "over time." What time is that?
(image below)


(image above)

I asked my mechanic last week - and he seemed to believe it was what I surmised to be a "rolling average" or something like that. Not sure if that is true - since it's been 12+ years since he worked for VW/Audi. But it sounds plausible.

My guess of the day is that perhaps I get a good ride because the "rolling average" has not been calculated yet after a reset. Then, slowly but surely - something causes that "optimum damping" to go downhill?

Just another theory since nowhere to be found are any of the original Audi engineers who developed this frickin' system to help us. (Does anyone know how to contact any of the original people who were involved in the development of this technology?)

-----------------------------

Either way - on Wednesday - I am replacing my two front struts with the replacements I was sent under warranty. Just for shocks and googles. And then, hopefully, by the weekend, I can swap out the front acceleration sensors to further my obsession with rectifying this ongoing headache.

I just want it to work consistently and adequately.

As I've probably alluded to in previous posts - I'm really starting to doubt my sanity.

njroute22

The saga continues.

Today I swapped out the two front struts with the warranty replacements I was sent.

No change in ride quality. It is still bad. Amperage levels for the front struts in comfort mode are still all over the map (0.5a - 2.04a.)
----
Not much left to do.
1. I got my old Arnott struts back from my mechanic. I will test just the electrical part to see if amperage levels are affected.
2. I will swap out acceleration sensors when I receive them.

The last remaining piece of the puzzle are the rear level sensors. After that - I would have changed ever component directly related to ride control.

Not sure what to do next. How far can I go into this? I think if the above does not work - the next step is to ask Audi to diagnose.

njroute22

Just as an optimistic side note, I found an interesting thread on the ross-tech forums:

https://forums.ross-tech.com/index.php?threads/17758/

In that particular thread, they talked about (actual) faults in the acceleration sensors.

While I don't have specific faults (yet), it appears that if just ONE acceleration sensor is not operating properly, it can cause the whole system to go bad. And in my opinion, could feasibly send bad data to the ECU, which could possibly be the reason why my whole ride stinks.

My current theory is that one acceleration sensor has some partially faulty internal wiring, capacitor, or circuitry inside, which is throwing the whole system out of whack.

Based on what I've tested, it is hard to figure out which one(s) they are.

Unplugging both front sensors gave (poor, but) uniform readings across all four struts. Unplugging just one or the other front sensors gave exact readings for the front pair as if I had both plugged in. That, to me, doesn't seem logical.

I'll do voltage readings of pin 1 (+) and pin 3 (-) for the front two sensors as a start. It will add some data to my troubleshooting workbook. I wish I knew this before I spent 8 hours at the shop yesterday (we had the rear right wheel and liner off, which would have made it easier - now if I want to DIY I have to jack it up at home).

However, since I don't have "open or short to ground" faults - it leaves me a bit uncertain. The rear struts seem to be operating to spec when it comes to amperage. But then again, the possible failures of this system are still relatively uncharted based on what I've read online. Maybe I have a "first" of some kind.

dvs_dave

It’s certainly a clue as to how the level control ECU works (Bentley uses same system). Seems like if one accelerometer is bad, then they all fall over. This logic applies elsewhere, namely the TPMS sensors. One fails (excl. spare) the system stops working.

So definitely something to dig into more,
as all 3 sensors are the last piece of the puzzle to be fully tested.