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ADS-II Suspension...got the Holy Grail

8K views 22 replies 17 participants last post by  ka707 
#1 ·
Well fellow ADS-II sufferers, you know my pain on this one. The WIS is woefully incomplete regarding this system, as is alldata. For the most part, ADS-I diagrams and components are shown, and are mis-labeled as ADS-II. This creates a huge problem with shops not knowing WTF they're doing. Even the bleed points shown in WIS are not accurate.

Steve Brotherton was apparently aware of a german-language version of this thing and managed to track the english one down, so now I have come into possession of the entire 162-page ADS-II factory manual. This material is pre-labeled for insertion in WIS, and was apparently slated for inclusion, but for whatever reason MB never actually did put it in. So accordingly, 95%+ of this is not found in WIS.

I would like to post this, so that it is available to those who need it, but am unsure of how to host a large PDF for display on this site. Maybe a mod can help me?

This should really help clear up the mystery surrounding this system.
 
#11 ·
Hey no problem, guys. I am happy to help, as all of you who've followed my 18 month ADS odyssey know, I have been through hell and back with this system, due mainly to a lack of available information.

This should help solve that problem for others. This info wound up of great help in getting to the bottom of my own problem, since knowing how it all works, you could rule out any mechanical faults. The problem this whole time ultimately turned out to be the ADS-II control computer, which was fried but barely functional enough to check out OK on a self-test through SDS. Amazing anybody ever figured that one out.

Steve Brotherton finally took half the car apart and had all the wires running to the damper valves plugged into an oscilliscope he rigged up inside the cabin, and then he realized what was going on when he'd drive around and the control unit was sending no signals out at all. No signal = all valves full shut.

The front half of it that communicates with the other modules and to OBD was OK, but the part that actually sends signals to the valves was fried. So it thought it was working, but it wasn't, the valves weren't being modulated at all when going around corners (explaining the sloppy handling), and they also weren't being adjusted for road conditions so the ride stayed board-like.

Initially it was extra-confusing because the hard/soft switch would work sporadically, even though all the computer-controlled functions were dead. The switch would soften the ride, but the handling was then extra sloppy. The system has no valve position sensors or any way to know if what it thinks it is carrying out is actually being done, so when your $tealer plugs it into SDS and measures the valve responses, it's all based on the assumption that the control module is working properly, since that component has no real independent test.

Anyways, this manual really should help take the mystery out of this system, it contains detailed directions for proper fill and bleeding, and for the replacement of each individual component in the system, so I hope people will be less scared of it now. If you go to a shop, just print this whole thing out and bring it with you.

Even if they subscribe to startech and WIS, almost all the info they get about this system is completely bad, mostly ADS-I mis-labelled as ADS-II. That's why most of them can't even figure out how to bleed it. I had two indies and a dealer telling me it was the spheres, or it was this or that, all of it wrong. One even told me it was self-bleeding when he couldn't find the bleed points listed in WIS.

Wow. Man. I am just happy it's all working properly finally. And FWIW, with it working right, the car handles and rides amazingly well. Steve says based on what he saw with his scope, the system does compensate for body roll during cornering, by controlling the valve positions as the weight is being shifted. Apparently it takes in all the data from the trraction control and ABS sensors, so that's where it's getting the steering angle and pitch/yaw data to do that from.

I know bobterry and I went back and forth awhile ago about this, but the system does more than I think we thought it did. It doesn't raise/lower the shocks on each side of the car during cornering like the R230, but it does control body roll with valve positioning. It can shut the valves along the axis that weight is being shifted along, and it cuts body roll that way. I figured it must do something like that, because the handling gets so wallowy when it isn't working right.

Anyways, I think I'm finally done with this nightmare. And if anyone has any questions about it, look up SteveB on the peachparts forum, his shop basically learned on my car, since they went through the entire system, down to measuring the proper electrical control signals when it is working right. At this point they could answer any question anybody might have.
 
#17 ·
Not to be difficult, but I just tried the link I posted and it works. If for some reason it doesn't, delete the last part (the /.pdf) and it'll take you to the page. Click on the symbol, not the previa...

If your profile had an email I'd send a copy, if 29mb is doable.
 
#19 ·
Hi, I just purchased a '98 SL600 Sport, put on new spheres (the fronts were full of hydraulic fluid), and am nonetheless getting an ADS light about half the time. Also the ride is not quite what I was expecting for comfort anyway. Is the ADS-II manual still available? I'm looking forward to getting into troubleshooting this.

Also, where can one get the SDS for a more thorough checkout of the car?

Thanks!
 
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