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After frustrating night, edit to post:

Decided to swap out front passenger air shock, because noticed that when I sprayed soapy water onto top of shock, it would bubble from under the shock damper nut (middle nut topside of shock). This would sag my front when left overnight or for several hours parked.
Wanted to swap out so the compressor does not get burned out overworking to pump shocks every morning and afternoon.
Before doing the work, compressor would eventually pump gas into front shocks, and it would eventually go up, even though took time to get this to occur. Probably up to 5 minutes before I got to be able to raise car to high setting, but would work fine.

Shock arrived. Swap out was fairly straight forward. Also swapped out upper control arm while I was at it (yes, the shock must come out to do this - because of the way the side arm bolts are located, nut on outside of arm, bolt on inside facing shock wall).
Connected the 4 wires at top of shock (I dont think there is a way to connect these wires wong - even though two are 2 wire connections, and then the air line, and another sensor). Maybe one of you knows better.
Anyways, everything put together, car was still on car jacks, preset to height normal to when driving. 
I turned the car on, and eventually heard compressor turn on but for a short time. Assumed it is because car is on jacks still and does not detect the low height.
Turned car off, lowered the car off the jacks. Got back in. Started. Within about 1 min heard the compressor kick in. Saw car raise a little while sitting inside.
Opened the door few times to try to set more compressor work. It was hard to hear the compressor with the car running.
Eventually I saw the car raise a couple more times, but the height of the car did not go to what I expected it to.
Gently backed out of driveway, very slowly drove straight line and back into garage. This did not raise the car at all.
At that time, the car was not raising anymore. All the way down on front both sides.

Since compressor was working before the swap, my thinking is it would be too coincidental to have compressor go out.
Same with valve block. Way too far to be affected.
The only things I can think of are:
- relay replacement
- compressor refresh to do
- sensors on shock not working right or not connecting right

Had suspension failure red icon on display. Cleared with Durametric, but appears to come back.
Errors are in PASM area:
789 / 315

Also just spoke to the shock folks and they say the sensors need to be calibrated. Guess it is a possibility, but wonder how likely. 
Would have to tow car to a shop. Really irritating.
Any help will be greatly appreciated.

Edited by ciaka
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Yes, I did turn off suspension  before the work, and managed to turn it back on after work (pressing button for 10 s).  Saw the message suspension turned on.

Tried to raise car, but did not.  

The shock tech keeps saying sensors need calibration first. I will go look at the sensors again to see if they are the culprit.  One is for control of air volume into shock (on off center on top of shock).  Not sure what the other one is (top center where the damper nut is).



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I was able to verify my air suspension compressor does work and is functional.  
I managed to slip 2 low profile jacks under car and raise the front to level I measured before starting work. 
Then connected durametric.  Cleared faults. 
Then was able to notice that suspension was disabled again (must have happened after suspension fault error was flagged).  Pressed button for 10 s to enable suspension once again.
Then noticed compressor start pumping again.  Both front and rear shocks were raised.  
I stopped and started car 3 or 4 times, to see if compressor pumps up the shock on its own over time.
The rear seemed to have been adjusted properly.  Front driver appeared to be slightly lower.  Front passenger (where new shock is), does not hold height.  
After having compressor run few times, I lowered the jacks to see how the car would sit.  Driver frt was lower but up a bit, pass frt kept going all the way down.
So the new shock is not getting pumped.  It is possible that the system does not have enough pressure to pump up the frt pass. shock.

Spoke to shock person, who states calibration is needed especially in Panamera.  I was hoping to go without the calibration, as this will require me to get towing to my house, get the car over 40 miles to shop.  Still trying to find solutions for pumping.  If you have any suggestions, keep em coming.  I will be trying again today. 

One thing I may try just thinking about it now (please stop me if you dont think good idea):
Maybe what I should do is disconnect the air line, raise car up as high as can to extend the shock and put air volume into it.

Then connect line back and lower the car.  Some of the air volume will be part of the gas volume, and could at least allow drivability.  What do you think?

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Tried to raise car, remove line, to see if shock expands.  No.  Shock not expanding.

Noticed when disconnected line from shock there was no compressed air in it.  That was after compressor ran couple times already (and ran a couple times previous day too).

So thinking is, either the block or compressor not working right.  There is nothing else that can go wrong here.  ECU working since does give me warnings chassis failure, if I raise on jacks, I can press button to raise suspension to high, even though I do it on jacks to simulate, so ECU does work.  Mechanical connection to upper arm was re checked.  Seemed just fine, cleaned contacts just in case.

Reseated     top of shock connections too.


My next move - replace valve block and/or compressor rod/seals with rebuild kit.  My logic is, even though compressor working, may not be generating pressure (although thinking why the back would raise then).
Compressor seemed to sound differently too over last week or so (along with the typical pumping noise, noticed a deeper sound associated with it). 
I assume my newly installed shock is fine (no reason to doubt it at this time).  Re checked all connections, disconnected shock from air line, after compressor ran for a while, and noticed there was very little pressure in the line (almost no hiss of air at all).  So if no pressure in line, either valve block not opening, or compressor not generating.

Let me know what you think abou this.

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So been playing with car more. 
Saw compressor run, and this time, clearly saw front pass side rise. Had car standing freely off jacks. But over time, saw frt pass side slide down.
Could not figure out what the hell.
Inflated shock with shop air and placed finger over valve to stop air escaping, and there was no sound of anything coming out. so shock appeared ok.
Saw valve block and sprayed with soap, no bubbles, all ok there.
I already checked the driver side last week for leaks, but decided what the hell, recheck. So take cover off, and what do I see? Leak bubbling from same spot that happened on passenger side.
So now I am buying another shock for sure before I proceed with any other stuff.

Question is, would a leak in one side cause other side to be sagging too? I know if left sags it automatically makes right side lower too, but my question is specifically about the air leak itself.
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  • 2 weeks later...

I have got to know the suspension pretty well.  Long story short, will likely have a nice write up. 

Easy once you know the parts and their operation and expected behavior, etc.

One of my new shocks happened to be DEFECTIVE.  So waiting for 2nd replacement to shove into the front pass side.

Everything else seems to be working, car raising, compressor working, no leaks observed, BUT front pass side slowly drops.  Since no leaks in lines, internal fault strongly suspected.  

Once it is all re swapped, I can update.  Been fun though.  Great thanks to my CTT for having another Pcar to use while toying with the PTT.

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