MaxLTV

I've got a red "Chassis system failure" message a couple of weeks ago when driving up to the mountains (2011 Cayenne TT with PDCC). On engine restart the message went away. No message after that.

Then again, same road, the message happens again. This time after engine restart it came back almost right away, but then disappeared after driving more. Then on the way back it appeared and disappeared few minutes later, then appeared again and stayed till engine restart.

I googled, and it seems to be related to air suspension issue - either compressor or relay or one of sensors. It's strange though that when my message was on, ride was noticeably harsher, but the ride height seemed normal. With the range Cayenne has, I'd definitely notice if it was all the way up or down. Both times it happened on longer drives and during colder than normal weather, but could be a coincidence.

What would be the best way to diagnose it? Most likely it's coming out of my pocket, so want to be sure it's not something small before dealer goes all in and replaces the compressor and half of the suspension.

Torre

I'd say with high probability that you have a faulty sensor, that's all.

Nurburger

Had a similar issue on my 957. Not sure what differences there are with the 958, but I would start by checking the 40amp fuse that controls the air suspension compressor. If this is blown, replace and listen for the compressor - if its running continuously then you will need to replace the compressor relay.

MaxLTV

Thanks. I'll check the fuse. Any way to check the relay?

I'll also try reading the codes.

vchris1987

I have a similar issue that i noticed it while driving off the garage ramp when the weather is very cold. Air suspension works fine for me but it disables driving modes. After 2 restarts of the engine the message dissapears and everything works great!
Someone told me that might be PDCC related but I have an appointment on Thursday with the dealer

colowhisper

I've noticed this on occasion with my 957 w PDCC. Only happens at high elevation in cold weather, so seems to be air pressure/temperature related to me.

garrett376

I bet you're in for a new air suspension compressor. Mine (11 turbo) needed that after a trip to the mountains in the snow. Dealer told me it's common for the dessicant to freeze up once it's spent and then it can't pump anymore.

colowhisper

^^I bought the rebuild kit but haven't installed it yet, will that alleviate a new compressor?

nodoors

Can't guarantee until you verify it was the seals, but it should.

MaxLTV

Mine is same year and happens only higher up and below freezing. My wife just mentioned it first happened to her over a year ago once, also at high altitude and below freezing, but has not come back since. Now it happened on two separate trips but same conditions. The moisture freezing up explanation makes fits, but if that's the case, removing moisture should do the trick. They should just make replacing desiccant a part of periodic service.

garrett376

That'd be nice, but from what the tech said to me, there's no way to service it beyond getting a new pump.

MaxLTV

Any benefit in getting this fixed at a dealer vs. independent, assuming it's out of pocket?

deilenberger

The shop diagram doesn't show or mention dessicant for the 958 series. The use of nitrogen in a sealed system obviates the need, supposedly. The advantage of having a dealer do it, they have tools and experience, but they may cost more.

MaxLTV

Noticed one thing - when the suspension gets er-adjusted the compressor keeps working 2-3 times longer than normal, raising the truck higher than normal, and then the truck does Pshhh and lowers to normal height. That to me seems like the relay is getting stuck for a little before it lets go. Does it make sense to start with just replacing the relay?

J'sWorld

Guessing on these vehicles doesn't make sense. Porsche has you by the ***** with the need for PIWIS.