Extreme cold PSM failure turbo

[Dominicandude]

Sorry for such a crappy First post.

2010 Pan Turbo 48,000 miles. I can still hear the compressor going but the vehicle will not go up nor down. The ride height was still good until we attempted to roll it on board ramps to get the car on a lift (was in Sport plus ride height when failed). Once we brought it off the lift on to the board ramp after visual inspection of all lines under the car the suspension is now tucked in on the rear with Low Vehicle warning. I’m told the compressor fails at these -15° temps we had when it happened but like I said I can still hear the pump going and attempting to raise. I don’t nor did I ever hear a hissing sound. Is there a way to put air into the system in order to drive it to my Indy shop. I replaced the relay but that did not fix anything I don’t know if I should replace the Compressor or the valve block. I’m an aircraft mechanic so doing the work myself isn’t an issue since I’m not under warranty anymore BUT how do I know which one has failed the valve block or the compressor? . Never had an issue until this extreme cold weather. Code currently on my Snap-on computer is U0418 (Fault, PSM control unit) and I once had a U0447 (check gateway control unit fault memory content)  a while back but when it was reset that U0447 never came back. I’ve looked for answers on other forums but couldn’t get the warm and fuzzy to buy the compressor since mine is actually still pumping. If I keep the battery connected the compressor will continue pumping (shutting off the compressor 5 minutes or so at a time) until the car battery completely dies. Need help.. Tried to post image but limited to 2MB sorry 

[ciaka]

I hope to give some insight on air suspension from Cayenne turbo view (own one for several years), and my Panamera Turbo (just recently got it).

 

It seems that air suspension is a frequent headache for cars it is mounted on (CTT, PTT, etc).

Often, it is the compressor that is the failure.  It appears to stop pumping efficiently.

Other culprits, are other join points - at valve block or at each shock.

 

To me, I would assess as follows:

 

If entire car does not raise/lower, and you hear compressor working:

- I would first check junctions by putting some soapy water see if you can observe leak.  After that, I would suspect compressor

 

If one of shocks misbehaves (does not raise/lower):

- check junction points for that shock at valve, at shock.  Then, level sensor.  Then valve block  (although I dont think there would be anything else in there other than leak at connection)

 

 

For compressors, there appear to be 2 options:

1.  Replace entire compressor - I would do this if compressor is just ceased or does not work at all (after checking appropriate relays/fuses, etc)

• This option for Panamera is going to be expensive - looks like $600-$1000 for a replacement compressor

2.  Recondition kit for compressor - there are kits you can buy, remove compressor, replace the parts (I think its piston, some other sleeve and seals)

• This option runs about $50-$100, and would require removal of compressor, taking it apart to replace parts.  More time consuming but substantial less $$ involved

 

Hope this helps.  Let us know if you already fixed yours, and how, so the thread can have some closure for future DIYers.  Thanks.

 

 

[Loren]

I have heard good things about the rebuild kits. Of course the proper installation is important.

[ciaka]

I was just at the dealer here in Austin.  Discussed suspension among other things.  He said the shocks sometime fail (bellows no longer hold air tight when worn).   This causes often the compressor to work all the time, burning it out.  Told me it is quite normal to park Panamera in garage, and overnight it would lower (some air loss).  However, as long as when car is started, it pumps up, it should be good to go and continued to be used.  

I am getting no issues on any PTT suspension yet, but noticed takes longer than Cayenne turbo to inflate/change level.  So started contemplating doing recondition of compressor internals.  See kits for about 60 bucks.  Worst case wont make a difference.  Best case, will pump more efficiently, therefore turning on less often.

BTW unless car is engine stopped, it is kind of hard to hear that compressor turning on/off.  Does anyone else hear it well when engine is on?