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    Transmission Control Module Replacement

    Many Cayenne owners find the vehicle has a throttle response problem, a delayed response to throttle input. This has been discussed many times on this forum and other forums as well. Some refer to it as "lurching". The symptoms are a one or two second delay after you press the throttle before the car begins to accelerate. It is especially noticeable going around a corner. The delay seems attributable to the transmission often being in too high a gear for the task at hand, not downshifting to the correct gear soon enough and also a delay in the drive-by-wire throttle itself.

    In the US there was an undocumented fix that involved a DME update, some call it an e-gas update. I have had this done on my car and many others in the US have had it done as well. This did seem to improve the throttle response such that, if the transmission was in the correct gear, response to throttle input was pretty good. As far as I can tell though, the DME update did nothing for the transmission shift mapping. It still seemed to be in the wrong gear far too often and slow to get to the correct gear.

    I have recently seen reports of the transmission issue being addressed with a replacement of the Transmission Control Module. Supposedly the model year 2005 version, possibly part number 955-618-022-11, has significantly improved shift mapping. One dealer has reportedly replaced the module on several customer cars who complained of the throttle response and they have all been happy with the result. All delayed throttle response symptoms were gone. Another dealer took the 05' module from a donor vehicle and installed it in the older car with good results.

    I don't know if replacing the transmission control module will cure this issue or not. I am reasonably sure that the transmission shift mapping is not software updateable so replacing the control module does make sense. Whether or not the 2005 version has solved all the issues, I don't know.

    I believe there will be additional information and developments on the control module replacement over the next few weeks. As I become aware of new information I will post it here. I would certainly like to hear from anyone who has had this done and what their experience has been.

    Re: Transmission Control Module Replacement

    I sent that stuff in with mine last night Gary, I will report later today.

    Re: Transmission Control Module Replacement

    Thanks Mike.

    I am talking to my dealer but they don't know anything about it.

    Re: Transmission Control Module Replacement

    Update.

    PCNA Want my dealer to swap out 3 modules (DME, Auto Trans and I other ??) from a new 05 S. None available at my dealer so they are being sought for replacement soon, probably next week.

    Dealer says PCNA experimenting, want to see how it works in real world situation, but they think it will (Know it will ?). Also they ordered new remotes (range improvement)

    More later

    Re: Transmission Control Module Replacement

    Wow! That's one responsive dealer!

    This sounds fantastic Mike.

    By all means, keep us informed. Thanks for the update.

    Re: Transmission Control Module Replacement

    Gary

    I am not holding my breath

    haha

    Re: Transmission Control Module Replacement

    I have an appointment with my dealer for next tuesday. I don't think he will use the 05 S 3 modules. But he said that he installed it in some Cayennes before. Hopefully it works ^^

    Re: Transmission Control Module Replacement

    I have a brand new '05 Turbo and I have to say I love this car as much as I love my GT-3 (for obvious different reasons). As a backgrounder, I also race a GT-3 Cup car, not that it makes me any better judge, but just to give you context.

    I have never driven a pre-05 Cayenne, but the '05 Cayenne still has an issue with being in too high of a gear. Disabling PSM does remove this issue. What I do to drive this better is I manually downshift two gears when I am ready to pass or when I enter a corner aggressively. Both solve the problem.

    I don't believe that Porsche will address this issue because I suspect it has to do with fuel consumption. The Cayenne (as are other cars in automatic mode like the Ferrari 360) are mapped to conserve fuel, not for spirited driving. I do wish that if you select sport suspension setting you get the transmission mapping of when PSM is disabled. Barring that, or aftermarket, I will bet Porsche will not change transmission mapping.

    Charles

    Re: Transmission Control Module Replacement

    I'm not sure this has something to do with fuel consumption.
    I also got a different gearbox ECU unit and there are some improvements but not even close to what I expected.
    The gearbox shifts smoothly and fast, I don't think this is the issue. I think the real issue is E-Gas setup, how fast the throttle responds.
    It is even much worse on the Cayenne Turbo because it also has to do with the turbo chargers, how fast they react and how fast the boost pressure jumps in and at what level.

    Some of you will be surprised to hear that VW Touareg owners complaint about the same issue, so this isn't just the fantasy of some sports car spoiled Porsche hardcore Cayenne owners but a reality.
    I prepared a nice "answer" to the latest attempt to try to fix my throttle/shifting response and I hope Porsche takes it more seriously this time.
    I truely think that Porsche knows the problem and I also think they have a solution at hand. But maybe this solution is too expensive (exchanging black boxes, certification, etc.), too dangerous for a lot of Cayenne drivers (spontaneous throttle response on a 2.5 t monster is something you have to know how to handle because you also have to brake) or maybe, and this has been my personal experience too, some Porsche employees (mainly tech reps and engineers) don't see the Cayenne as a sports car.

    If so, why doesn't Porsche just put back the VW badge and charge 10000 bucks less for this truck?
    There is a lot at stake here for Porsche, especially regarding their reputation to build the sportiest SUV on earth. My Mercedes ML55 AMG has almost the same throttle response like my 997 Carrera S with the activated "sport" button of the chrono sport package. Whoever drove a 997 with this setup knows what I mean.

    Yes, I'm disappointed. The Cayenne Turbo is such a great SUV, classy interior, great quality, never had a real problem (now 8300 km) and the suspension setup is unbelievable for such a heavy truck.
    But I never owned a car (not SUV!) where the throttle/shifting response sucked more than on the Cayenne Turbo. Porsche MUST address this issue fast!

    Finally, I think the throttle/shifting delay can be addressed with a modified engine and e-gas software mapping only, maybe with the need of some sort of adaptation to the gearbox ECU software mapping.
    Yes, this would involve cost and yes, it can be excluded that a lot of customers who never made complaints about throttle/shifting suddenly want this "fix" too, substantially raising retrofit cost for Porsche.
    But it is Porsche's fault that it came so far, they could have handled customer complaints at discretion AND with satisfactory results. Unfortunately the results weren't too impressive up til now. I wonder if Mr. Wiedeking really knows about this issue, the Cayenne is his baby and I'm pretty confident that he wouldn't be amused.

    Re: Transmission Control Module Replacement

    I am getting some very interesting feedback from sources who wish to remain anonymous. Thanks guys! I am more sure now that the control module replacement is a solution that Porsche is experimenting with. It does look like it will become available on an individual basis if you have your dealer speak to their PCNA technical rep.

    I am also beginning to wonder if the problem might be solved differently on the Turbo than the S. At least one Turbo owner who I spoke to thought so and he got that impression after talking to a PCNA rep.

    This situation is still evolving but I think we are finally getting some attention from Porsche. I also think fixing this problem means more than just making the Cayenne more sporty. When you're trying to merge onto a freeway and commit to an opening in fast moving traffic, only to find your car can't deliver on the commitment you've made, that's a real world driving problem.

    BMW and Mercedes make SUV's that don't have this issue. They have very smooth and responsive throttles and shifting. There's no reason the Cayenne shouldn't do as well as these competitors.

    Re: Transmission Control Module Replacement

    > If so, why doesn't Porsche just put back the VW badge and charge 10000 bucks less for this truck?

    Shouldn't that be more like $25k - $30k less? While the Cayenne out handles the ML55 in the curves, the throttle issue doesn't make it anywhere near as safe around town or on the Interstate.

    Thinking about it, just putting the VW badge on it might just do the trick. At least VW appears to have a TSB related to this issue.

    Re: Transmission Control Module Replacement

    > I manually downshift two gears when I am ready to pass or when I enter a corner aggressively.

    Have you tried 'blipping' the throttle? Once you get the hang of it, the transmission seems to downshift twoish gears even faster and more accurately then 'tipping'.

    At the same time why should we have to do play tricks just to have a 'safe' vehicle that doesn't randomly die on us coming out of a corner or merging into high-speed traffic?

    > The Cayenne (as are other cars in automatic mode like the Ferrari 360) are mapped to conserve fuel, not for spirited driving.

    I would not generalize this to 'other cars in automatic mode'. While you're out of my league with the Ferrari, I can say that this is not the case with AMG tuned automatics (even in an SUV).

    The way a ML55 transmission, even a 2001 model, acts around town (without driver intervention like tipping or blipping) blows away the Cayenne. I swap between an ML55 and a CT frequently. Not only do I _not_ miss the Cayenne's transmission and throttle stumbles around town but I feel much safer with the ML's consistently. For that matter I don't remember my around town time spent in any other ML or X5 being anywhere near as disconcerting as the Cayenne with the quirky transmission and the unsafe stumbling throttle response that I experience on my CT.

    Does my CT rock on high altitude twisty mountain roads or out on an ice track? Yes! Do I blip the throttle going into a turn when I'm pushing it? You bet. Do I love it when I can drive it all out? I'd be a fool not too. But I can't drive it all-out with inter city speed limits of 30-40Mph.

    Re: Transmission Control Module Replacement

    Quote:
    bancu said:
    Thinking about it, just putting the VW badge on it might just do the trick. At least VW appears to have a TSB related to this issue.



    VW TSB #01-04-13? (LINK)

    also NHTSA #10008078 (NHTSA TSB search page)

    I have read comments from some Touareg owners who have had this done and they seem very positive, cures their symptoms. Other owners say they can't tell any difference. The TSB itself describes symptoms that only partially fit the Cayenne's behavior that we are discussing here. The TSB is also to address a harsh 5th to 4th gear downshift. What's that all about? I haven't noticed that happening to my car.

    Also, the fix supposedly flashes the transmission control module. This doesn't fit what I had been told previously, but, I do believe the VW and Porsche modules come from the same source. The TSB looks official and is on the NHTSA website so I think we must conclude that there is software residing in flash memory inside the control module and that it can be reprogrammed. Interesting.

    Re: Transmission Control Module Replacement

    Oh GM you are good. I missed that NHTSA posted the TSBs. Thanks. That's a much easier place to search.

    Although the VW TSB isn't an exact match, some of the postings on one of the Touareg boards map closer to our experiences:

    http://forums.vwvortex.com/zerothread?id=1494632
    http://forums.vwvortex.com/zerothread?id=1494193
    http://forums.vwvortex.com/zerothread?id=1525070
    http://forums.vwvortex.com/zerothread?id=1533286
    http://forums.vwvortex.com/zerothread?id=1538702

    They reference a "death-lag" and "California stop" problem which I think is similar to what we're encountering.

    I agree that the fixes VW have offered have mixed reception with the Touareg owners. I think one owner put it best when he noted that 'it happens to some people and not others...but those that it happens to it happens to often'.

    I think the VW TSB shows that their is taking similar issues like ours a bit more serious than Porsche. Do they care more about their customers or could that be because they've been forced to?

    I noted to PCNA at the beginning of July that I consider this a major safety issue and will file a complaint with NHTSA if it is not corrected. Your pointer to the NHTSA site got post got me thinking.

    I did a search in the complaint section of the NHTSA and it looks like Cayenne owners are being much more kind to Porsche then the Touareg are. There are over 13 posted complaints related to this topic lodged about the Touareg and only one about a Cayenne Turbo.

    Could the ability of VW to flash the transmission control module be related to the tool/computer they're using? Maybe Porsche can't do this with the PST2. Maybe the PIWIS will address this. Hmmm...that makes me wonder if my dealer has a PIWIS.

    Re: Transmission Control Module Replacement

    Look at NHTSA #10007493

    Re: Transmission Control Module Replacement

    Good catch but...

    Given the date and title, it looks like NHTSA #10007493 maps to Porsche TSB W418 which is only for the Cayenne (v6).

    It talks about there being a possible loss of performance at high RPM only on the v6 and lists pages of v6 VINs that are effected.

    Re: Transmission Control Module Replacement

    Right. That's V6 only and a different sort of problem.

    Re: Transmission Control Module Replacement

    I heard that there will be a DME upgrade for the "S" in August.

    Re: Transmission Control Module Replacement

    Quote:
    bancu said:
    Could the ability of VW to flash the transmission control module be related to the tool/computer they're using? Maybe Porsche can't do this with the PST2. Maybe the PIWIS will address this. Hmmm...that makes me wonder if my dealer has a PIWIS.



    Good guess. A few weeks ago, Porsche had to exchange the gearbox unit for a new software version while VW was able to update the software with a simple CD used on their System Tester. PIWIS should be able to do the job, the question is WHEN?!

    Maybe Porsche is a bit more generous if they don't have to exchange the hardware.
    Right now I'm preparing a much more "harsh" letter to Porsche but I'm still waiting to send it because of the factory vacation. I want the right people to be around when they get it.

    What also annoys me is exchanging the brake discs at 8000 km (they had cracks and were almost "finished") and my tires (all 4!) are already gone too. This really is ridiculous, if Porsche claims they build a REAL Porsche SUV, the tires can't last only 9000 km or so. Not to speak about the brakes.

    Re: Transmission Control Module Replacement

    Gert is confirming this SW change.

    Re: Transmission Control Module Replacement

    I'm short of outa my league with this one...since I dont have any driving experience with a Cayenne...but from what some of you guys have said it definately sounds like a transmission issue. There are some automatic cars out there that have the exact opposite problem, that is the car is constantly trying to pick the right gear. This is obviously really annoying so my guess is Porsche wanted to steer well away from that problem. Apparently they went to the other extreme .
    The only way to solve the problem as I see it would replace the Transmission Control Module so as to have a more "aggressive" transmission shift mapping.

    Hope my 2 cents were of use

    Re: Transmission Control Module Replacement

    Quote:
    Mick said:
    Gert is confirming this SW change.



    It's probably worth pointing out that Gert is noted twice that this update is for the CS (no mention of the CT) and this is for RoW. No word on the US yet.

    Re: Transmission Control Module Replacement

    My car was checked by the dealer. The service manager is my good friend He told me that my car is running the newest software and it has nothing to be changed. However, he just gave me an interesting news on how to cure the lurching and everything.

    The problem I have with the car is, when I drive slowly, the gearing seems to have problem. The next problem is when I put on reverse and put it on D, it will make a noise.

    These problems will all be fixed by my dealer with a magic touch

    Re: Transmission Control Module Replacement

    I had a 2001 Audi 2.7 T A6 that had this problem. I complained many times about this and finally traded the car for a 2004 A8. The A8 has the opposite problem, too touchy on the throttle. I would much rather have this problem than the previous one. Since there has been much engineering on the Cayenne that seems to have come from Audi/VW why don't they go to the source and find the solution?

    Re: Transmission Control Module Replacement

    RC and GM Austin: I am sending you an email on what is exactly done to my car.

    Re: Transmission Control Module Replacement

    Quote:
    Mick said:
    Gert is confirming this SW change.



    See this link for Gert's information and additional discussion on this topic: web page

    Re: Transmission Control Module Replacement

    I still don't know what the answer to this issue is but I'm convinced more than ever that Porsche can fix it if they want to.

    I drove new v8 and v10 TDI Touaregs recently. Both of their throttles seemed to be more deterministic in their responses then my Cayenne in similar situations. This could be from my limited evaluation since I can never predict or force the hesitation in my CT 100% of the time. It is the unpredictability that makes it so unsafe to me.

    Neither Touareg seemed to upshift any where near as soon as my CT does normally around town. Again, I didn't have them for weeks so this is not a sure thing.

    The sport setting on the Touareg transmission is a sure thing. It is a joy to experience in town. It seemed to have either Touareg upshifting and downshifting much more aggressively then even spirited (not hammered all-out) driving in my CT. Sport mode also locks out sixth gear. Both of the Touregs also started out in 1st gear at a stop (which my Cayenne won't do automatically even with PSM off). All of these observations were made without disabling ESP on either Touareg. All of this makes me wonder why the sports car side of the Cayenne/Toureg twins can't and didn't offer a sport transmission mode along with the sportier handling they gave us.

    What was also telling is that the v8 Touareg seemed to be more 'clunky' in its downshifts. (Writing this makes me really wished I had checked build dates.) The v8 'clunky' downshifts (and this _could_ have been limited between certain gears) were par with Tipping down my Cayenne from 2nd to 1st at a stop. Downshifts in the TDI were _very_ smooth and I don't remember and 'chunking'.

    Re: Transmission Control Module Replacement

    We're still watching this issue and we're "working" on it, don't give up hope. As soon as people at the factory are back from their vacation, I start sending them letters again. And I bet they already have enough paperwork on their desk regarding this issue from other people.

    Re: Transmission Control Module Replacement

    I continue to get some private mail and e-mail regarding this issue as well, although nothing definitive. Some people are waiting on parts. I do now know two owners who have had their transmission control modules replaced and it did not cure their symptoms. In spite of that, I also have hopes that we will see new developments and solutions for this problem in the near future.

    Re: Transmission Control Module Replacement

    Quote:
    GM Austin said:
    I continue to get some private mail and e-mail regarding this issue as well, although nothing definitive. Some people are waiting on parts. I do now know two owners who have had their transmission control modules replaced and it did not cure their symptoms. In spite of that, I also have hopes that we will see new developments and solutions for this problem in the near future.



    If it is indeed a "certification" issue, Porsche should finally take care of it and get it right. I suppose a lot of cost is involved but I want my Cayenne Turbo to drive like a Porsche, not like a...well, I don't have even a comparison.

     
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