Cayenne 1772 chassis system error

[MarkGolf]

Hi Guys,

Got a new problem on the GTS, recently replaced my air compressor due to the power wires snapping clean off.

Bought and fitted an eBay unit, seems to do the job just fine however, I did find that it was running a bit more often than it should, every few mins, it comes out to top up the air, so clearly a leak.

I did get an occasional error with "chassis system error", when this happens, it doesn't allow the car to go to the very higher or lowest level and sometimes, no sport mode.

Checking codes, 1772, signal lead for pressure sensor.

Did some investigative work and found some air leaking from the brown air hose which is the tyre compressor supply, where it meets the swivel output joint.

Fresh cut hose and some sealent for security, no more leaks.

Thought this may stop the compressor coming on, it seems it needs to come on everytime I raise the car, as if it does not use the air tank supply and I still get the above 1772 error. I'm not sure if this is triggering due to pressure falling below a threshold.

Right now, I'm stuck, the air suspension operates fine, remains level and at the height it is left at, even after 5 days of no action, I've used soapy water to spray around the air compressor and distribution block during inflation and after compressor switches off and there are no leaks. The only thing I have not check is if it is leaking through the exhaust, if that is possible but otherwise, I have no clue as I have not disturbed any other areas.

I have a basic diag tool and I can see the system pressure drop off within just a few minutes. When the error occurs, it doesn't allow the accumulator valve to work and I guess this is where it stores the air to allow a fast increase in suspension height without using the compressor.

Do I have a leak, does it need calibrating, is my ebay compressor crap, what have I missed?!

So, I'm stuck, if anyone has any clues as to what I can do next, that would be great!

Other issue is coding my ballast, PIWIS is the only way of doing this right?

Cheers!

 

[YPVS]

When I rebuilt my compressor, I had a leak on refit.

It was one of the 6 hoses going into the valve block on the back of the compressor.

If the ride height is OK, it may not need calibration. I did mine recently with my PIWIS II clone. It was level anyway and kept height, but after entering the gaps between tyre edge and wing for each corner, it set itself about the same, just slightly higher at the rear.

What does the stance look like?

 

[MarkGolf]

Morning!

Stance is fine, sits perfectly normal. Until the error, it lowers to each level, raises to it but while raising, it is using the compressor.

One thing I just thought of, is to pull the exhaust hose off, where it meets the front wheel arch liner and see if air is leaking out here, just to see if there is an internal leak somehow. The pressure is going somewhere and it's not from the shocks.

Had you undone the hoses at the valve block? I haven't touched mine but the soap test didn't show any leaks.

I can only think that the system tries to build pressure or fill up an air tank but it then leaks out so I'm taking a guess at a leak coming from the compressor itself, internally and out through the exhaust or some route along the blue hose which i believe goes to an air tank..

Where did you get your piwis clone from?

Cheers
Mark

 

[YPVS]

The block I'm on about came off as part of the compressor as one unit.

Just checking my old screen shots and I had a 1772 DTE after rebuilding the compressor as one of the codes. I cleared this and it never came back.
My main issue was 1776, no signal or communication to the level control switch. After fitting 2 switch units and 2 control units, I found a fuse on the feed to the switch in the PIWIS interactive wiring diagram, F44, which the manual just has down as "heated headlight washer" in the RHS dash fuse panel. This was missing, not blown. Someone must have stolen it to solve another issue before my ownership.

On refitting it had 3 goes at topping up the system and getting the car to ride height, producing two red error messages in the process. After fitting F44 fuse and clearing the codes, it's been fine.

 

[MarkGolf]

Morning!

Stance is fine, sits perfectly normal. Until the error, it lowers to each level, raises to it but while raising, it is using the compressor.

One thing I just thought of, is to pull the exhaust hose off, where it meets the front wheel arch liner and see if air is leaking out here, just to see if there is an internal leak somehow. The pressure is going somewhere and it's not from the shocks.

Had you undone the hoses at the valve block? I haven't touched mine but the soap test didn't show any leaks.

I can only think that the system tries to build pressure or fill up an air tank but it then leaks out so I'm taking a guess at a leak coming from the compressor itself, internally and out through the exhaust or some route along the blue hose which i believe goes to an air tank..

Where did you get your piwis clone from?

Cheers
Mark

 

[deMort]

Mark .. email me .. [email protected]

it's too late for me to go through this now but i'll do it tomorrow night ..

 

[YPVS]

Morning!

Stance is fine, sits perfectly normal. Until the error, it lowers to each level, raises to it but while raising, it is using the compressor.

One thing I just thought of, is to pull the exhaust hose off, where it meets the front wheel arch liner and see if air is leaking out here, just to see if there is an internal leak somehow. The pressure is going somewhere and it's not from the shocks.

Had you undone the hoses at the valve block? I haven't touched mine but the soap test didn't show any leaks.

I can only think that the system tries to build pressure or fill up an air tank but it then leaks out so I'm taking a guess at a leak coming from the compressor itself, internally and out through the exhaust or some route along the blue hose which i believe goes to an air tank..

Where did you get your piwis clone from?

Cheers
Mark

When I removed my compressor, it came off in a frame of 3 bolts, with the valve block as part of the frame. I was rebuilding the original though, not replacing with a Chinese aftermarket unit, even though I have one sitting in a box.

The PIWIS II clone came from here...About a 30 day wait and around £300, but as far as I can see, identical to genuine. It even came with a SN sticker, not attached for some reason, probably a legal loophole in China.

https://obd2.market/product/porsche-piwis-2-tester/

And the PIWIS virtual machine build to put on a laptop from the |Google Drive links here..

https://www.planet-9.com/threads/piwis-2-setup-as-a-virtual-machine.238021/

Someone wrote an INI file later on in the thread to open the PIWIS virtual machine with no need to faff about with dates.

It's pretty normal for the compressor to come on to replace air used to raise the vehicle. How long it stays on for is the key. Mine is only for a few seconds, 10 or 20 at most for a full lower then raise.

Don't forget it loses air every time you lower.

 

[MarkGolf]

New compressor resolved this!