Matt C

My Cayenne spent a day at the dealer. The following things were fixed:

• Cardan shaft replaced
  The vibrations between 50-60mph seem to be history (at least on the way home from the dealer - time will tell ... ). The service rep told me that mine was one of the last to get a new shaft. If there are others with the same issue, they will have to "realign" the shaft according to new specifications!
• PCM Software Update to Version 3.0
  Software was updated, but I believe that the update to the Navi failed (see separate post)
  It seems that they are preparing for a "voice-driven" version since there's an entry in the "software-version" menu!
• Tailpipes replaced
  Black paint on the inner side of both pipes was falling off so they replaced both
• Cats replaced
  The "emission control" warning light was constantly on (they had cleared the fault memory several times suspecting a software error but every time it came back on a couple of days later). Now they simply replaced the cats.
• Rear window drip drip fix
  Ya know that ....
• Roofrails and roofstrips installed
  Adds a nice touch (IMO of course)
• Driver door realigned
  Side molding on drive door touched the body (but only when opened strongly) due to a slight misalignment of the door.

As regards an update to the DME/tiptronic: There's no official update available yet (service guy was in a Cayenne tech training two days ago and asked about it). Besides a slight hesitation to downshift in corners, I've had no real issue with the behavior of the transmission/shifting so it's OK for me to wait for an official fix/improvement (I've never had a problem with the lurching thing anyway, either because my Cayenne hasn't it or my feet are so sensitive).

Have a good weekend!

GM Austin

I think it is very possible European Cayennes do not have this same issue. If you think there is some hesitation, some "dead pedal", coming out of a corner, this is the lurching/hesitation I am referring to. Keep us posted on your impressions as it relates to any behavior like this.

Matt C

GM Austin,

I'm not sure that we're talking about the same things or that I understood everything correctly (probably because of my English knowledge).

Having followed all the threads about these issues, it is my understanding that there are three different problems, which I would summarize as follows:

a) The Lurching: Mudman2 described it on rennteam as follows: The lurching is a hyper sensitive gas pedal which gives passengers whiplash in slow moving traffic with lots of stop starts

b) The Dead Pedal: It's like the Cayenne is taking some sort of a pause for thought before applying the amount of gas the driver is telling him to. It's like an acceleration hesitation.

c) The Hesitation to Downshift:
Coming out of a corner the Cayenne is usually one or two gears two high to have in enough power to accelerate.

Unfortunately, I don't have the technical knowledge to assess whether they are related or not.

I don't feel that either a) or b) are present on my Cayenne. Concerning a) it could also be that I've developed a hypersensitive foot to avoid the danger of headbanging for my passengers (and I don't have a lot of stop-n-go traffic on my daily commute).

Only c) is an issue for me, but not a real big one. It could also be that I just have to drive it more like a robber coming from Fort Knox to avoid it.

ltc

Matt C,

I am curious about your dealer's comment on the Cardan shaft issue:
"The service rep told me that mine was one of the last to get a new shaft. If there are others with the same issue, they will have to "realign" the shaft according to new specifications!"

My Cayenne was in this week and they did try to align the Cardan shaft with a new Porsche fixture. After road testing, they determined the vibration was still present and ordered a Cardan shaft. I should probably check next week with them to make sure this is still the plan.

Toby, care to offer your thoughts? Just remember, a Porsche parts plane from Germany to Texas HAS to fly over Boston

GM Austin

I think your English is fine Matt. You don't seem to have any greater difficulty here than any of the rest of us.

I like your response. We need to do more of this where we are more descriptive with the words we use. I have applied the Lurching description to the things you catagorized as Dead Pedal and Downshift Hesitation however your definitions seem more appropiate actually.

The hypersensitive gas pedal, the thing you describe as lurching, is something that I believe occurs when the DME is using an aggressive mapping. You get a lot of engine braking when off the gas and the transmission stays in a lower gear longer giving you instant throttle response. I get that when I turn off the PSM. It's a little too aggressive for normal city driving but great when your racing around country roads.

I think the standard mapping for European Cayennes may be more aggressive than the US mapping. I am not sure if this for emmissions or fuel effeciency or maybe just an impression of driving styles. Whatever it is, I feel certain it does exist and there is less of a hesitation problem in Europe.

The Dead Pedal, IMO, is just another manifestation of the Hesitation to Downshift. After the transmission downshifts and the motor is at an RPM with more torque, the dead pedal goes away. The Cayenne has that feature of holding a gear in a corner to maintain stability and that may be the part of the mapping that delays the downshift. The lateral accelerometer plays a role in this decision.

There are so many sensors and shift mappings providing input to the DME. It has to be a programming challange coordinating all of this. I think we will continue to see DME updates that put new mapping parameters into the shifting behavior and we will continue to get more refinement from this vehicle.

gig

Does anyone know what production date (approx) that they started installing the new Cardan shafts? My S has an October 2004 production date, I have no vibration between 50-60 mph, etc.

Also, is the vibration VERY noticeable? is it violent or subtle? just curious...

Matt C

Lewis,
I was just quoting my dealer's service rep regarding the cardan shaft alignment vs. replacement issue. Unfortunately, I don't have any further details. Anyhow, I am convinced that if the alignment turns out to be without any effect, they will have no other choice but to replace them. It might as well be that they gave out this order just to gain some time to increase their stock of shafts and avoid growing lists of customers (with Toby on top) waiting for a replacement.
And once a replacement is authorized (as it seems to be the case for yours and Toby's car) I think it's very unlikely that they change plan.

Gig,
The vibration on my Cayenne was not very strong but still good noticeable. It was the strongest on the driver and the front passenger seat. But even more obvious was a "humming" that came along with the vibration. The combination of these two made it very annoying. It started at 50mph but was gone over 60mph. It was the strongest while driving in that speed range but without any acceleration or breaking (just crusing).
According to a post from a well informed person on rennteam.com, it seems that they started implementing the new shafts in the production lane after the christmas holiday in January 04.

GM Austin,
Thanks for the compliments.
I also think that there are different mappings for US and European models. Maybe I'm wrong but wouldn't a more aggressive mapping lead to a higher consumption? This in turn wouldn't be very desirable in Europe (much higher fuel prices and stronger sensitivity towards fuel consumption).
As regards the Dead Pedal and the Hesitation to Downshift, I'm not so sure that the former is another manifestation of the later. With my car, I notice a Hesitation to Downshift as follows: Coming out of the corner, I press the accelerator to speed up. But the car is in the wrong gear and to do so. After a short moment, the downshift occurs and we're ready for takeoff. It should have downshifted during the deceleration while entering the corner. This is my issue. I wouldn't call this a Dead Pedal. The engine does respond immediately, but is simply not in the right gear to have enough torque to fulfill my "orders". Don't get me wrong, my Cayenne does downshift when decelerating or even breaking, but usually not enough. As you wrote, solving this issue is probably the most challenging task for a "DME"-Programmer.
I think I've read posts of others who had experienced a "real Dead Pedal" where the Cayenne didn't react at all for a moment (especially when accelerating after a stop). This was the reason why I separated the two issues. However, I have not experience this with my Cayenne and I don't ever want to (knocking on my head/wood as I'm writing this).

mudman2

That followed the theme Gary, very interesting.

GM Austin

Your speaking of his description of the post corner downshift hesitation aren't you?

mudman2

yep

T2

Can anyone confirm whether the Carden shaft is only on the S's or also the TT's??? Curious. T2

mudman2

Both as far as I know

GM Austin

It is definitely on both and has problems on both. Not all Cayennes are affected though, for example, I still do not have the vibration and I have a 7/1/03 build. Maybe it will come later.

Torags

Mine is an early July build also. No vibrations so far. They must have been paying attention at the Skoda factory.

camcayenne

I think it was in the cayenne book where it states that lateral sensors (G sensors) hold the gear in that gear whilst cornering to ensure stability - it was specifically designed to hold the gearbox from up-shifting mid bend, but I guess it works the other-way too to ensure that there isn't a marked change in torque, to the rear wheels in particular, that could result in loss of traction and a slide. Good driving technique dictates that you should not change gear whilst cornering as it upsets the balance of the vehicle ( To those racers out there I agree that it is not the fastest way to drive, but it is the safest - I am police driver trained). If I am 'making progress' with my cayenne then I slot it in to manual and drop a gear or two BEFORE the corner, thus giving me torque to balance the car through the corner and power to accerlate once I have gone through the corner.