kosmo

FOr about a month now I've noticed the PDK "jerking" while downshifting from 2-1 in SPORT mode. This does not happen in the NORMAL mode.
I mainly drive in sport mode and this jerking is becoming frequent.
The dealer couldnt replicate the problem, of course.

Anyone else experience this? tks

StanThePorscheFan

I experienced this when I test drove one almost two years ago. Ended up getting a stick because of that experience. But to be fair, when I shift from 2nd to 1st in any mode, and engage the clutch a hair too late - it jerks too.

Just my 2c

Mike in CA

I'm surprised the dealer couldn't replicate the "problem" as it's not that unusual. In Sport mode PDK is designed to provide quicker and more positive upshifts and downshifts. Unlike Normal mode, in Sport mode engine torque is hardly reduced during shifts which results in firmer gear changes. I notice that my PDK sometimes is less smooth in low speed down****s in Sport mode but that seems reasonable to me since Sport is a performance mapping strategy and I'm asking the car to run that program while creeping along. It's like trying to shift a manual box quickly at low speed and slow acceleration; the shifts aren't going to be as smooth. With PDK, that's what Normal mode is for.

ADias

I suspect the dealer did not replicate what the OP experiences because it depends how it's driven, namely braking profile. If you come to a stop as a limo driver, in SC Sport, you may feel the extra engine compression offered by 1st gear. BTW, the same can happen in a manual transmission, user-dependent. PDK is a solid connection to the wheels - there's no cushioning hydraulic torque converter or a user-feathered clutch at work. It works, as it should be, AFAIC.

In stop-and-go traffic it's best to drive in SC Normal - I actually prefer manual mode. Sport is for the open road and Sport Plus is for the track.

P.S. - If you start the car in reverse, stop it, and then move forward there 's also an hesitation, perhaps related to brake assist, which is normal.

mstams

Yes. Some of us know exactly what you mean. My car is an early build 2009, and I experienced this from the start. I posted several times about how mine had a very abrupt downshift from 2-1 in Sport Auto mode just before coming to a complete stop. It never happened in Normal or Sport Plus Auto and never in any Manual mode.

For me, it was not the expected "quicker and more positive" shift. It could be downright forceful and even nearly neck-snapping at times -- so much so that passengers would laugh and ask me, "Whoa! What was that?" I worried about it for quite a while. Some suggested it was my driving style, so I tested every different stop approach technique I could think of with no success in reducing the jerking effect.

Then, after my break-in period I switched to driving exclusively in Manual mode. Basically, I gave up on the Auto mode because I hated the immediate upshifts in Normal and the stopping in Sport was just so bad. I didn't even touch Auto mode for quite a while after that. But then the weirdest thing happened.

There were a few posts about the issue disappearing for some on this board and others. I decided to switch back to Auto Sport and give mine a try. Believe it or not, mine had disappeared, too. Not really sure what happened. Was it the number of miles (~3,000)? Was it not driving in Auto for so long (~1,000)? Did I change my style (don't think so)? Whatever it was, it was gone.

Today, I still drive in Manual mode. Every so often, I switch back to Sport Auto just to check. Once or twice I've noticed a firm downshift but never as harsh as before. So maybe you should just give it some time. Let us know if yours disappears as well.

Mike in CA

Interesting. My car is a late 2009 build and I've never experienced the violent 2-1 downshifts you describe. Was your ever car at the dealer, ie is it possible they updated your software without telling you? Just a thought.....

mstams

Don't think so. I did have my DME control module replaced last fall for DME/DFI miscommunication after getting a PDK Transmission Emergency Run fault. Didn't mention this in my earlier post because I still had the harsh downshifts after it was replaced. TMI... Plus, after reading others who got this same message later due to low voltage, I tend to think it might have even been a misdiagnosis due to newness of PDK at the time. Strange thing was that others had the same symptoms disappear as well. They may chime in as well.

ADias

You had your DME replaced and you are not sure you got the update? Of course you did - standar procedure to update firmware/software when DME is changed. But regardless of updates, I have seen that behavior demonstrated or avoided as a function of how the vehicle is driven.

mstams

That's not exactly what I meant. I don't think I've gotten any newer software updates that fixed the issue without being told. I still had the symptoms after replacement. The disappearing act happened later after driving nearly 1,000 more miles in manual mode.

As for how I drove it, I literally tried every conceivable stop approach method I could think of over a period of 2,000 miles. That was a lot of stop lights, and I could never find a pattern. Then, poof, gone. And still gone after 6,000 more.

mambodoc

Same downshift deal with my C4S PDK launch car. Very abrupt and noisy (thud/clunk). I was under the impression that it is a software fix and planned to have it looked into when I am able to make it over to my dealer. Now have about 20K mi. Apart from this, AOK.

kosmo

youre right, the roughness occurs when im slowly coasting to a stop (LIMO as you say) rather than under hard braking.

75% of the time I drive in Manual in NORMAL Mode so its not a major concern for me. I find that in AUTO-NORMAL mode PDK upshifts too quickly-different topic tho.

Whats interesting/concerning is that the rough 2-1 downshift in AUTO-Sport mode doesnt happen all the time.

IS there a PDK software update? The dealer said no. Tks