how low is low?
 

Reading a bunch of threads about air suspension woes. The term "low rider" appears a few times with complaints so low that the tires might hit the inside fenders. Off and on, I see the green light but it generally goes off. A scan shows, "turn off due to overtemp". Up till a week ago, the green would come on and go off after a few minutes driving. After sitting overnight, all options "Lift, Comfort, Automatic, Dynamic" are also illuminated. If I select any, I see the up or down arrow, but nothing seems to happen, then the yellow comes on and lift options is not iluminated.

2006 A8L 4.2 gas. US car.

For a week, the yellow also comes on after driving for 5-10 minutes. In addition to "01577" turn off over temp, I also get :

01583 - Leak detected
01400 - Suspension level control

I sprayed soapy water around the pump and all four struts. Can't see any bubbles but my eyes are old so maybe too slow to detect. Also cannot hear the pump running but it must be at some time to get the "turn off, over temp"

To my knowledge, it is not riding low, but then my question. "how low is low"?

Measuring from garage floor to edge of fender, I get about 28.5" for all four with a variance of less than a 1/4". I've been checking this just about every day for a week with a stick with a clip on it at 28.5" to see if it is getting lower. (It's not)

I can't tell any difference in the ride (except a plethora of Michigan pot holes that the governor wants to raise our gas tax .45 cents to fix)

Occasionally, after sitting overnight, the green light isn't on, but after driving a bit, it lights and stays lit, then the yellow.

I can reset the codes and yellow will go out but not green.

I can't hear the pump running or hear any air leaking

If someone wants to chime in, fine but for starters can I get someone to measure for me?

So, sounds like a leak to me.

FWIW, I thoroughly leak tested both of the two fronts that have eventually gone bad on my 2006. In NEITHER case did I have any bubbles. There are just too many places the air could escape without picking it up reliably with the soap test. Many other owners have reported the same, yet 90+% of the time leak issues are at a strut, and mostly in front.

Put it in jack mode to lock out the compressor and then let it sit. Now see if it drops overnight. Compressor run is really quiet on mine. Could never hear it with motor running, and feint even with it off.

Just roughly, I had a couple of inch gap from fender to top of wheel in daily use if set to either Comfort or Automatic. If you have sport suspension, it is 20mm/close to an inch lower. If gap to tire is slim to none, especially if a non-sport, it is not stock ride height.

Finally, given age of these cars, unless you know history, a prior owner might have modded it to lower the ride height too. The maximum permitted mod height drop via a re-coding mod is typically 17mm down relative to stock starting point. Then with combo of a 17mm drop and a sport suspension, top of tire visually could get close to top of fender wheel well cut away. For a non-sport, if you select the "Dynamic" mod, the resulting drop is close to the sport suspension, so then maybe an inch off tire if not modded, and near top of tire if modded t the max.

Thannks. I turned jack mode on at about 8:PM last night. It's been sitting in garage since then . Height of fender lip from garage floor hasn't changed. Looking at tire from fender, there is more than two inches clearance.

I was really hoping someone could give me a measurement in inches from the floor. As mentioned, mine is about 28.5"

I don't know if the tire size affect this measurement but mine are Pirelli Cinterado's 255-40-19

Ross tech has a page on this, see attached link.

Ross-Tech: VAG-COM: Suspension Level Control Calibration

You need to measure from the center of hub to the fender, tire inflation, size and other factors can throw off measurements, so Audi requires center of hub as a point of reference.

A8 4E standard suspension is 416 mm front and 398mm rear center of hub to bottom of fender

Hope this helps,

Edit:
According to the Ross tech page, you need to be in calibration mode with the VAG COM, I am not sure if the above measurements are relevant in normal or automatic mode.

Ross tech Level Control

I don't have measurements but when I had terminal leaks either front or rear (yes i've had both) the top if the tire was full into the wheel well. So if you still have a gap you're doing ok. Lift mode however should get you probably 4 inches between top of tire and bottom of fender from what I recall. I'd gone through 8 rebuilt struts before I dumped the factory air and went with some custom coilovers.

If you want a 100% sure leak test for the struts:
Take out the strut, place it in a BIG (100l+) water container filled with water and pressurize the strut to normal operating pressure.

Then you WILL see air bubbles if you have a leak.

This is the way I test all air equipment for leaks. And this is the way I will go when testing my leaky front strut.

Had a leaky hydraulic tank (hydraulic pressurized by air). I repaired it, then leak tested it this way. Has been without a leak for now a year (it has a pressure gauge).

Haven't measured from center of hub yet. Seems like it would be less accurate to eyeball the center of the hub. However, it's been about 40 hrs since I put it in jack mode. Measurements from floor to fender haven't changed.

It doesn't seem to be an issue driving, but I don't like looking at the yellow and green lights, plus the "turn off / overheat". I concur that it must be leaking but gotta be verrrrrry slow leak.

I'm also not planning on taking the struts off and put them in a big barrel of water.

I bought a pump rebuild kit just in case it's not pumping enough air.

Would you drive it like this?

If not in strut, you can also leak test at the air distribution block. Since you can access all the lines and the case for that part, soap testing does work there. Not as common a problem area, but occasionally comes up. When I diagnosed my strut (in car only), I leak tested the air block just to be sure the issue wasn't there since I came up empty with the simple in-car soap test on strut.

when I was working on mine the ground was about an inch or so from the bottom of the car. VERY low. I had a bad strut that leaked internally. I also had wiring issues and a bad rear ride height sensor.

Trust the audi control system, those warning lights are spot on, haven't seen them malfunctioned yet.
Green is low = leaky system
Yellow = over inflated
Both on = leaky system
All conditions are found here and fixed.
Cheers,
Louis