Hi all,

This would be my 2nd post here. I've browsed 6speedonline and other forums like Rennlist and such for advice and troubleshooting over the years for my cars and I thought it's time to contribute, and to let off a little steam here. I am/was an avid DIY'er with the 944's and even some aspects of the 911's but I'm extra hesitant to do anything myself on these Cayennes and I work out of town for 1-2 weeks at a time then get a few days off which I usually don't have time to touch the 955 for the most part.

I purchased my '06 CTTS car last summer around May so I've now had it 14 months, purchased with a little over 80,000 km on it, it now is approaching 110,000.

Since purchasing it, I had immediate problems that very day with the following, which for whatever reason the non-Porsche car lot had overlooked:

1. EGR valve failure
2. Notorious air suspension fault
3. One tail light bulb out on the passenger side

I was able to negotiate fixes on this on their dime, except for the tail light as it seems the seal failed and will require a new assembly... but I was responsible for the diagnostic time.

After that was fixed, I took it for a lovely drive from central Alberta Canada down a loop through Las Vegas, Nevada, San Diego, and then back up. I believe I put a total of 7500 km on it and then I had developed a strange sound/vibration the very day I got back. Upon closer inspection, I saw that the tread was actually cracked and seemingly peeling away. I can only guess the Cayenne sat for so long in the sun or that they had just come to the end of their life (through age, not mileage) this necessitated the following fixes:

4. New tires all around
5. 4-wheel alignment, as apparently mine was quite out.

Since that time, it mostly sat due to the nature of my work (remote northern work). It's become more of a weekend truck since late fall last year.

Some other minor work was required when I brought it out in the Spring again which included light maintenance, some light bulbs, door shims for a door that started sagging.

This summer I was able to open the wallet and look at getting some things done to the pig. I took it to the local Porsche dealership as they are notoriously picky and them go over it with a fine tooth comb. They located a small sweat on a seal at the rear main and said I needed to do the coolant pipes as there was some calcification and looked like a leak was starting and my brakes should be done soon (107,000 km).

In-between all of this I experienced the other notorious "dipped beam" issue and had since replaced both HIDs at the same time myself.

At this point I read many many forum posts about what to expect, what maintenance to do, things like that and common failures of these vehicles. I was attempting to be responsible and order a new cardan shaft with the support bearing upgrade to replace mine, BEFORE an issue should arise, the coolant pipes, new brakes all around (x-drilled/slotted - yes yes save the hazing for later), and took it to a local Euro mechanic which has been around forever, and has always worked on my Euro cars.

I had them do the following:

6. Cardan shaft w/upgrade
7. Full transmission service incl. all gaskets, seals, filters, fluid, etc.
8. Coolant pipes - turns out I already had the aluminum upgrade, thanks Porsche dealership
9. Full brakes all around including parking brake, sensors, etc.
10. A few new hoses, 't' connector at the back, etc.
11. Look for where the damn water leak is that is soaking my driver's side mat - unsuccessfully
12. General maintenance on the engine

This was to all prep for the IPD plenum, CAI, bypass pipes, and tune from EPL. I wanted to make sure everything was in order before I did all of this. I also have some 22's (yes also save your comments about this) and some new tires coming.

Now my gripe: The bill came to just a tad over $5000 for this recent service. The Cayenne was parked in their lot and as I approached it, I noticed the black zinc was worn off the brakes, no one told me if the brakes had been broken in yet? I noticed a nice new scuff on the rear driver's side door (awesome job guys) and the interior wreaked of brake cleaner and several dirty dirty grimey fingerprints on the dash and window sill of the driver's side door. I started the Cayenne and was greeted instantly with a TPMS sensor issue, -2 psi on the rear wheel AND a dipped beam, headlight not working. I just replaced these bulbs not even 2 months ago now since I'm not sure if they broke in the brakes properly I go to to do, the transmission is shifting up HARD. I mean like +1000 hp rough clutch manual sort of hard, through all gears. Downshifting is like a dream, can't feel a thing. After getting the brakes broken in, I read some forum posts about what could be causing this upshift issue and I came across several things. So I enter a highway and attempt a wot 4th to 5th shift (PMS on, auto, not tip) and the tach bounces down, then up about 1k then finally shifts with a very, very scary clunk.

Now I have all these parts sitting here, the weekend all to myself to do them, and I can't do a thing as the shop is closed until Monday and I'm afraid to drive the Cayenne.

 

Wow, sorry to hear about all these problems. As for the IPD plenum, I would not recommend doing it based on a recent thread. It apparently gives no performance gains, only serves as a replacement for broken stock ones. I do not believe the whole cardan shaft needs replacement either if you do the upgraded bearing support, unless it has already failed. The wet floor mat could be a result of a leaking roof drain as the hose for it runs down the A pillar in the dash area. If you pull the side panel off you can see it on your left. As for the errors you are seeing now, I know on my range rover, if the battery is replaced / disconnected without following the correct procedure, a million errors pop up and the dash lights up like a Christmas tree.

Intake, bypass pipes, tune and 22s sound good to me!

 

Sounds like your transmission valve body solenoids may be sticking. Since you have changed the tranny fluid, it may be time for a new valve body.

Pricey if you buy new or you can get the valve body refurbished if on a budget.

Changing tranny fluid every 60,000 km instead of the stated 260,000 km prevents these issues from occurring.

 

$5000 sounds cheap if list 6 to 12 was done under this bill. When you say full brakes, did you replace rotor & pads as well? I still haven't replaced cardan shaft bearing, brakes (i.e. rotor & pads), and fuel pumps, which start to fail (have you replaced fuel pumps, yet?). Can't say much about the upshift issue since I don't have that problem, and nobody can help you with your shop experience (I had this happen at my local dealer but it got taken care of immediately). But, considering the mileage (or kilometers) on the car, your previous owner got away pretty easily. Only other thing that you haven't mentioned is the ignition coils but I am guessing it's been replaced before.

I recommend you to hire a hit man on this owner.

Seriously though, I can't imagine anything else fail on you. Best of luck.

 

You'll have to decide how much money an '09 955 CTTS is worth to you. You don't drive it much, you're going to have to continue to put money into it just to get it perfect - not to mention "modifications". Any vehicle that sits most of the time will develope issues MUCH faster than those driven regularly. At minimum your are dumping $5,000 a year into (based on your last year's maintenance). This is likely to continue as it appears that you purchased a vehicle for which most routine maintenance was not performed. I would never have a Porsche that I didn't drive regularly. Additionally, I would find myself a reputable mechanic/dealerchip that you can trust to do your work.

 

My luck is nearly the worst. I ordered this part, sitting in my garage for weeks and experienced that thump/wobble the day before it was to go in the shop. Checked it out and it was the shaft. Good luck.. or bad luck?

Unfortunately it's not running down the A-pillar but rather the footwell near to the accelerator, pretty much directly parallel with the dash itself. I might post a picture if I'm not describing this well enough.

I was thinking that too, about the valve body that is. It really could be a number of things including bad/dirty connectors, oil/etc. getting up that braided cable to the TCU, literally a laundry list of possibilities. It's back in the shop for the full week again to fix these. The guy at the counter mentioned the valve body had oil/liquid on "both ends of it" and they "cleaned it off". I was quite confused as to my understanding they farm out their tranny work to a local transmission specialty shop


This is good to know, thank-you. I'm not really a big believer in following the manual with respect to maintenance routines, I see it as a minimum and anything done ahead of that is only beneficial.

Items 6-12 sadly do not include parts (aside from anything transmission-related. I always supply my own parts, why pay that mark-up, oil companies typically supply their own materials now because they were tired of paying +10% mark-up for "nothing"! I replaced rotors and pads, sensors. No lines, no calipers, they said calipers looked and operated well.

The engine was actually replaced by Porsche under warranty at the 32,000 km mark and there were coil issues in the 2nd year from what I gathered from all the previous maintenance records, and headlight issues early on as well. I haven't done the fuel pumps yet and that's one piece I'm sort of debating doing now or waiting until they fail.

Unfortunately due to the nature of my work it only gets driven on the weekends, and sparingly at that. Maybe if I'm back in a major metropolitan centre I'd make it my DD, instead of this terrible truck! I'm at the point now where I had to put the money into it and I will now be stuck with it, never to recoup a penny. This car sat a lot of the time with the previous owner too which didn't help but routine maintenance was done, looking over the records.


That's just it, these guys are well known and have been around for half a century. I guess the regular mechanic was tied up on some exotics so they had some newer fellows on it.

Fingers crossed they solve this so I can actually enjoy the thing this summer.

Thanks all for the input and opinions. I'll post some pics here with the rims, euro side markers, new brakes, all that esthetic stuff. Still looking at tail lights and I can't make a decision (old ones have failed seals so condensation is quite present in them at times) otherwise I'd leave 'em.

 

I agree that it sounds like a sticking transmission valve body. Did you make any progress with the shop on this yet?

 

Dropped it off Monday morning, calmly explaining the issues (did I mention p/n/r/d all lighting up too?) And I didn't even get a "sorry". I work 3.5 hours away so I had to leave early from work to pick it up just before close and dropping it off also made me late for work the following monday.

No call or correspondence at all yet. Just curious how a valve body would suddenly fail or would this be related to the servicing?

 

When I first bought my CTTS, it too had the fully illuminated transmission gear indicator lit up like a Christmas tree. Mine ended up needing a new TCU and wiring harness from the transmission; turns out that transmission fluid had wicked its way up the harness and created havoc with the TCU. Only good part was the transmission fluid/filter were "serviced" well ahead of the specified interval. No issues since the repair.