CTT air suspension warning - fix or go to springs?

iamtheari · 12-08-2013, 11:16 AM

My 2004 Cayenne Turbo has been bulletproof through its first North Dakota cold snap. It starts on the first or second try, warms up quickly, heats the cabin well, etc. the heated steering wheel, mirrors, and seats are on par with anything else I've driven. The one exception is the air suspension.

The first morning it hit -20F, I started it and let it warm up while I showered. By the time I got in to drive to work, the air suspension warning was displayed. It has tended to be on more than off since then, coming on within one minute of starting the engine. The compressor can be heard struggling before the warning comes on, and once the "recharging" notice was displayed until it gave up.

My best guesses are the pump having given up at 132,000 miles and -20F temperatures (consistent - the daytime high the past two days was -15F or worse) or the front air shocks leaking and now reaching the point of no return.

Best prices I can find are $30 for new pump seals, $620 for a new pump, and $415 per corner for new shocks. I also found at least one kit to convert to traditional springs all around for $2,000.

Losing the air suspension would be annoying because I wouldn't be able to adjust ground clearance to get lower on the freeway and higher in deep snow or rough terrain, but it would make the car basically bombproof to run up here in the great white north. What input do people have on this choice?

mtnrat · 12-08-2013, 06:09 PM

I am up here in Canada and have had two winters with the air suspension. From what I have read here and on rennlist the air susp on these is one of the most reliable around as well as the easiest to fix. I bet your compressor needs some work. There are some DIY instructions around.

iamtheari · 12-08-2013, 06:23 PM

I'm glad to hear some positive comments from our warmer neighbo(u)r to the north. I know of a $30 parts kit to replace a couple of seals in the compressor. I am not normally that lucky, but it's worth a shot at that price.

mtnrat · 12-08-2013, 07:05 PM

That is all most seem to need to fix the issue. Good luck.

914-6Porsche · 914-6Porsche's Garage

My 04T had that problem up until about 6 months ago. It needs a new ring in the compressor that is located under(or above) the removable panel on the passenger compartment side. It's about a 2hr job. I don't recall where I got it online but it was about $200. It comes with detailed instructions. Search for a Wabco Compressor upgrade kit.

iamtheari · 12-09-2013, 04:43 PM

I have a parts kit coming from I6 Automotive. $30 on eBay, assuming it arrives intact from across the pond. I hope I can get the 2 hours to do it soon. I'll have to use my parents' unheated garage because, unlike my unheated garage, theirs does not actually freeze up so I can work in relative comfort at 35F.

I have read and it looks like I need my T27 socket to remove the panel, then pull off electrical connectors, then a 13mm socket to remove the bolts, then more T27 bolts, and then you can pull it apart enough to replace the O-ring.

Did you have any damage to your air shocks themselves?

iamtheari · 12-10-2013, 07:52 AM

In my daily experimentation this morning, I disabled the air suspension before starting the engine. I let the car warm up and then drove off, finding that the air suspension warning did not come on. The car is at proper ride height now. I am going to let it sit for the day and see if it falls again. Variables: This morning it was 16F outside, whereas the past few days the temperature has ranged from -25F all the way up to -6F at one point on Sunday.

This makes me think it is the pump seal giving up in moderate to extreme cold and working in normal cold.

914-6Porsche · 914-6Porsche's Garage

I didn't have any damage to the shocks. I'm kind of wondering what O-ring you had. My rebuild kit was the Piston ring and no O-ring involved. I guess the electronics senses when it reaches pressure and if it isn't fast enough the air suspension warning is activated.

914-6Porsche · 914-6Porsche's Garage

I just looked on Ebay and really need to check there more often. That is a bargain price for the kit. I thought it was outrageous for $200 but then again it is for Cayenne and many others.

iamtheari · 12-11-2013, 06:40 AM

There is a piston ring and an O-ring. I understand that the pump design had a couple of variations so some people need both seals, others only one. Of course, we'll see if the $30 kit actually shows up, being shipped from England.

island911 · 04-08-2014, 06:52 PM

fwiw, I also went the $30 re-ring route. (easy, 20-min's) ..but with problems ...

First few times no problem. Then later came faults, sporadically. It turned out that the plastic of the new ring sloughed off a bit and those fragments would catch in the reed valve, on the piston, holding it slightly open. After carefully cleaning out the flapper/reed and surroundings, it seems good.

Surprising that the system faulting sensing is so damn sensitive. ...but, then again, the dealers have to make their money some how. :-/

iamtheari · 04-08-2014, 08:12 PM

Is it really a 20-minute job? With my past experience on other 20-minute jobs, I think it will take me a half day to remove the pump and a full day to put it back in the car. The weather is finally improving enough to tackle this one but I am still nervous to begin. The warnings have only recurred once all winter, when it was below -20F as with the first time they showed up. Definitely it is nice to hear some positive feedback on the $30 solution, though.

island911 · 04-15-2014, 10:16 PM

You don't need to fully remove the pump, just drop it (keeping lines and electrical attached - three bolts). ..that happens after you drop the plastic under-body cover, that runs along under the passenger door.

Then just unbolt the pump cylinder head (2-bolts)

fwiw, I use an electric drive to speed the process along.