3ztwint

Hi all, long time lurker and lover of all things automotive! I've perused the forums for common 1st gen/955 CTT issues and have looked at several, but there is one around me that I'd like some advice on a few things if you would be so kind!

First off, I'm no stranger to other german makes and have had and personally maintained several Mercedes and BMW, and I'm not afraid to do some of my own wrenching and diagnositics (i've rebuild air struts, repaired MB PSE air lock pumps (for the door locks....yes it IS stupid to use pneumatic door locks and soft close actuators when every other manufacturer uses electric motors), coded key fobs using programs like AK90+ (so you don't have to pay the dealer to install a new DME/immobilizer when you need new BMW keys), etc...not saying I'm an expert on anything, but just that I should be able to handle minor to moderate issues if they arise).

So enough BS (sorry!) heres the lowdown on what I'm looking at:

Overall a very clean 2004 (approx 130K miles) CTT that runs smoothly and exterior is in great condition, as well is the leather and interior panels. There are three main issues that I saw (1-2 of which may be user error on my part/lack of familiarity with the CTT):

(first off major common things have been done at local Porsche dealer: coolant tubes, cardan shaft, and coils (only 3 replaced...if I get it I will just replace all remaining originals as a precautionary)

1. What level of boost should register on the right hand side of the cluster boost gauge? I drove it around a bit granny-ish and am ashamed to say I never exceeded much over 3500 rpm, I don't recall seeing the guage move but wasn't paying close attention - later while parked I revved to around 2.5K rpm and didn't see the needle budge...on other cars I've had that are TT's (no german makes though) and it seems that the boost guages would move readily even if a single turbo car and would show at least some small movement even at lower revvs (maybe build 2-3 lbs of booost?)...maybe I'm just not thinking right and I just need to go stomp on it and take her to 6K and see if it moves...my question here is: What is normal boost levels for a given rpm range? (from looking at prior posts it seems that even on the highway accelerating moderately you should see the guage move...those posters with no movement were later found to have a boost leak, often involving the N75 valve)

2. Transmission seems a bit harsh while shifting..still gets into each gear fine (under 2K rpm at 65+mph and had 4 'shifts' so was in 5th gear)...this isn't an earth shattering clunk, but just a bit harder that a benz or lexus...is is normal to have a bit harsher shifts on a Cayenne?? I was expecting if there was anything trans related it would be the 4-5 kickdown issue that was from a sticking valve body (or maybe this could just be the valve body as well if a typical CTT is silky smooth??)

3. Radio not connected...an aftermarket radio was in, but now the original unit with Navi is back in and I'm told the the present owner that he 'did not want to pay $1000 for porsche to hook it up....) should I assume PCM/elect issues (obviously we are going to the dealership the aftermarket unit was removed at so they can give the full story, but I wondered it it was a tell tale sign of issues (all other electronics work on dash and climate control etc). Anything to worry about here specifically or to ask the dealer about?

Bonus question: any other things I should look closely at/have the Porsche place look close at that are rarely discussed on here (ie that I may have missed in my common issues searches)? We are taking it to the same Porsche place it has been serviced at and it is also where 3 friends of mine (who have 993's, 911_50, and cayman) go to regularly (and they gave me the name of the 'best' mechanic to ask for for a PPI).

Anyways would greatly appreciate the input (and obviously the possible issues are priced into the car or will be on negotiation so I will be sure not to get it if the cost plus repairs approaches what a sub 90K mile example can be had for around me)

Thanks for all responses!! You all/this forum is a great resource!

ventoGT

2004 is the lottery year as far as niggling issues, but the cardan shaft and coolant pipes being done is a good thing. You don't say what the price is--that PCM/radio system not set up is a red flag and reminds me of the "AC just needs a recharge" problems--radios should be plug and play especially if it's the original unit, so that smells to me. The transmission could need a new valve body or it could just need new fluid, price it like it needs a new valve body.

Clean 100K mile 955TTs go for 15K on the high end--be choosy and good luck!

3ztwint

Thank you ventoGT! I agree definitely leaning toward giving this one a pass, price is 9.5K, but like you said there are many early 955 TTs in the low to mid teens...I guess this one was just tempting to look at because the seller is only 15 minutes from my house, but yes, I don't think the radio unit is going to be anything easy, so even if everything else checked out that would be probably too big of an issue - great analogy, it's totally like the 'a/c just needs recharged'! Haha, my thoughts exactly, when I saw it in there and it wasn't hooked up and the radio unit being a know issue in 04/05s I was pretty skeptical as any easy fix would have just been done. I'll see what the dealership says, but at this point I think this one isn't worth it given that even though its close, it would be much better of a deal to get a 100% example for 12-15K than pay 8-9 for something that could need 4k in work and have higher miles! Thanks for the input, I'm definitely on the hunt for a CTT or CS (seems like surprisingly they are only 15-30% more than a v6...), thanks again for the input!

dpatel710

Boost should peg at 0.6 bar at 2250 rpm and taper off to 0.5 bar under full throttle. I usually dont get into boost unless put my foot down some. The car has plenty of torque to get around normally. Also, I don't think it will build pressure when revving . The motor is limited to 3 or 4k rpm revving in park.

ventoGT

I'd recommend going for the TT--might as well, they are basically the same cost as a CS with a lot more HP and surprisingly they are equally if not more reliable.

buffstocover

This might be of interest to you. 2006 CTTS. I've had mine 2 weeks. 90k miles. Always serviced at Porsche. All service records. Always garaged. Bought from friend, and I know the original purchaser. Both adult, family guy, responsible owners with the $$ to not neglect necessary mntc. Coils have been replaced twice, coolant pipes and t's replaced under warranty, cardan shaft addressed.

At time of purchase I had Porsche do the following:
-Oil service
-Transmission oil service
-Both air filters
-Cabin filters
-Serpentine belt
-Front control arm
-alignment
-Spark plugs
-Repair rear camera wiring
-Rear hatch and window struts
-Clean sunroof drains and HVAC drain
-New wipers
-Install Denison 500SBT.
$5500

Just today, the following work was needed/performed at my request:
-New coolant reservoir (there was a leak that was dripping under passenger side by front wheel, and strong coolant smell)
-New engine torque strut
-New lower windshield trim pieces
-Change front and rear diff oil (mechanic said it was definitely due and probably original)
-New headlight molding gaskets and re-leveling of headlights
-New driver's door latch mechanism (opening door wouldn't turn on dome light or indicate door open to turn off auto re-lock function)
$1,900

Needed soon: front rotors and pads, new summer tires. $3,500
Also, very minor Turbo oil leak discovered today, likely needing replacement in next year or two, which means doing both turbos and motor mounts and whatever else while engine is out. I figure $5,000 more.

My mechanic said this was maybe the cleanest '06 TTS he'd ever seen.

I got a deal on it, but it's going to be $12k+ to get this thing totally sorted.

Hope this was helpful.

GDA

My 05 CTT will fully peg the boost needle since it has a GIAC tune on it. At any level of 1/3 or more throttle the needle quickly jumps off the zero boost line.

Trans shifts should be smooth and given mileage, you will want to discern if any of the following could be contributing to this "hard shift" sensation:

Broken or cracked lower control arms
broken or cracked main motor mounts
broken upper motor mount
broken front subframe mounts
severely worn front wheel bearing

Any of the above will create slack in the driveline that upon completion of a shift up or down can create a sensation of an essential "slap in the back" type feeling.

FWIW, a couple months ago asked the local Porsche dealer to change out all motor mounts on my 05 CTT and they indicated the service manager indicated they have never had to do these on a Cayenne. After an inspection by one of their "senior" techs, they indicated there was no issues with the mounts. I described to them that I had unusual vibrations when slowing to stoplights, random hard downshifts from 3 to 2 [very sporadic during a weeks driving].

Anyway, fast forward to me asking them to do it without their approval and guess what, one lower mount was completely broken and the other had collapsed by close to a 1/2 inch.

Things to look for:

Strength of hatch struts - failure is a every 2 to 3 year wear item
Main and secondary/aux electric fans - weak main fan will rear itself with creeping temp needle in slow traffic and cause needle to hit 1 oclock on the temp gauge rather frequently [fan is 600+ and an hour to change]
Vacuum hoses behind intake - change them all if no service records on them - you will gain a butter smooth idle and save yourself lots of random SAP errors and check engine lights for purge valve issues
Fuel pumps - a one to two hour job if they have never been done - if you DIY then do them before they fail

Rear suspension arms and rear wheel bearings - at your mileage its quite likely one or more is nearing end of service life so some suspension work could be in the next 10 to 20k back there

nodoors

@GDA

How much did your dealer charge to replace the lower engine mounts?
While they had the engine out did you do the coolant tees and o2 sensors or any other work?
Did it fix your vibration coming to a stop and the jarring 3 ->2 downshifts?

GDA

1 - $1100 labor for all three including the torsion top mount

2 - No since i had already done them previously there was no need

3 - Yes!