red95993

Thanks. Regarding your earlier post, I do raise and lower (mostly for fun) my suspension every few days. Just experience, but is you let something stagnate, it will become stagnate...has worked the last 35 years of my experience...

RESP

+1

JFScheck

I had the steel springs on my 2010 Diesel Touareg - liked the ride better than my V8 air suspension 2005 Cayenne S....

To each their own!

red95993

I spoke too soon, it went back into the shop. Same issues....

mcbit

I have to say, I couldn't correlate a rising suspension with a worn compressor.

Falling yes.

Slow Guy

I was wondering the same thing. Maybe default is raised and they pump air in to lower it?

J/K

mudman2

I assure you that is not the case :-(

red95993

What happened this time is I was showing my family how the suspension works (or is supposed to work!). I went from the "low" setting to the middle setting, then to the "high" setting. Not all the way up for off road though. Then I went to lower it back to the middle setting and it started moving real slow. I noticed that the compressor did not come on...This whole process took about one minute. Then had some knocking noises from the front right. Then the suspension warning came on...

I don't claim to know how the air suspension works yet. But it seems both times it failed is when I moved it more than two settings. It could be the compresser if it is not moving the suspension like it is supposed to.

Anyway it is back in the shop, I have a great guy working on it and hopefully will have an easy outcome.

Slow Guy

Don't you hate it when that happens?

ltc

PASM level sensing microswitches/sensors have had an issue with moisture susceptibility, especially at the connectors....you might want to start there.

Does your Indy have a PIWIS?
If a PASM P!g beaches itself, there should be a stored code.

red95993

He has a Durametric's (sp?) unit that he uses. He has pulled up a few codes, something like reading signal from pressure sensor, and control position (Codes 1772 and 1400). He is taking his time to make sure it gets done right and I am not in a hurry. If need be he can go to a local dealer and use (rent?) their PIWIS.

From what i understand the pressure raises the suspension, releasing pressure lowers it. Still not sure why it went to full high the first time...

ltc

Faulty sensor...

mcbit

I left the GTS for about a month and the suspension dropped to lowest which suggest to me it requires pressure to raise,

ArneeA

The theory of ops for the cayenne's air suspension should be very similar to the RR and X5's and possibly even the MB's Airmatic. My X5 has four corner air suspension as well.

It's a simple feedback loop with the hall sensors at each corner. HOWEVER, it isn't just the compressor. There is a valve body and a pressure accumulator tank. The valve body redistributes pressure where needed, depending on each corner's sensor.

The pressure accumulator tank stores air pressure to minimize load on the compressor, especially when minimal height changes are required.

The suspension module of course has timeouts, wakeup, sleep protocols and operate given feedback from the shock hall sensors for ride height and pressure accumulator sensor for storage. It will have outputs to the compressor and valve body.

If any one of these fail, it will yield an error. For our X5, which got the air suspension from the Land Rover (which isn't quite reliable), it has been relatively easy to understand. I had errors when the ECU needed replacement, when the airbags had a leak, when the pressure accumulator sensor was faulty, and when the valve body was faulty. "Luckily," these are the known items. If there's a leak in any of the 6 lines (4 corners + compressor to valve body + pressure accumulator to valve body), the it will be a pain to diagnose and replace the entire line.

If your truck hesitates or has issues with lowering and not raising, I doubt it's the compressor. It could be the valve body or any one of the sensors. Yes, it relieves pressure to lower, but to do that, the valve body has to do its job and the hall sensor has to transmit the correct voltage to do so. Granted, we're assuming that the suspension ECU is is in proper working condition.

When raising, the valve body, sensors, compressor, or pressure accumulator could be the culprit too.

ArneeA

By the way, as these cars "age," we will learn more about them. However, there is a company out there that sells superior air springs for replacement when the front or rear airbags have leaks and the OEM compressor (WEBCO). It's Arnott Industries. They specialize in air suspension parts for nearly every car with air suspension.

I've used their X5 front struts with thicker air spring material and have been happy to date.

The OEM WEBCO compressor for the Cayenne costs $620 from Arnott. I'm not sure why it's more, probably due to higher pressure and motor specs. Our S500's compressor only cost $350 and was very easy to replace.

The two things that I can not find from OEMs are the valve bodies, the suspension ECU, the pressure accumulator tanks. They are inexpensive enough, however, from the dealer, Suncoast, or Sunset.

Here is Arnott's website:

www.arnottindustries.com