Rough downshift PDK in automatic sport mode - anyone have it fixed?

[canuckporsche]

2009 4s PDK shifts in a rough jerky fashion in sport auto mode from 2 to 1 and starting to do same form 3 to 2. Has anyone got it fixed that they can share name of dealer, service person, copy of bulletin and/or name of PCNA person who understands issue and resolution?

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[canuckporsche]

Where are all the others that have this same problem? Any examples of solutions with documentation from dealer or PCNA?

[yrralis1]

It's normal . It's really NOT an automatic and under "sport" style shifting the downshift would be a bit stronger .

Yes its annoying. It will not do this in manual sport BTW .
I use normal auto in congested city driving or manual sport . That's my solution .
On the highway I use sport auto with over ride paddles .

[ghb]

Are you referring to the "thumping" sound in low rev (typically from gear 2 to 1)? I noticed the same issue with my wife's C4S. I also noticed the same "thumping" sometimes when accelerating from low gear (typically from gear 1 to 2). Do you have the same issue with accelerating? It is kinda annoying. I guess it may be normal if others have the same issue.

[stevepow]

I think this 2-1 abrupt downshifting may be "driver controllable". Not sure how yet, but I read something in the PDK info that makes me think it has to do with short stops and throttle lift.

As an experiment, I puttered around the neighborhood for a block or so between 10-15 or whatever it took to get the car to shift between 1st and 2nd back and forth and the shifts were as smooth or smoother than anyone could probably pull of with an MT and nearly as smooth as an AT - sometimes I had to look at the display to make sure. So the 2/1 shift in D-Sport can be smooth.

Now I need to get out somewhere clear of traffic and try some similar things with more speed to see if it is controllable with driving behavior. I think it is because about 50% of the time in D-Sport I get a smooth stop with no "jerk".

A couple of bits from the PDK info:

Driving in selector-lever position “D”, Sport active
...
Downshifts in deceleration state and deceleration downshifts are accomplished with
intermediate throttle application and are therefore audible.
...

• Prevention of downshifts in overrun state, e.g. approaching a corner (Fast Off)
If the driver decelerates, i.e. releases the accelerator pedal quickly, when
approaching a corner, the currently engaged gear is retained. If the driver also
actuates the brake now, downshifts adapted to the vehicle speed are performed
so that engine braking support is available...

• Downshifts while braking (Fast Back)
A downshift is initiated immediately if the driver switches quickly (within approx.
1 second) from accelerating to braking. However, the sportiness characteristic
and the selected mode dictate how early a downshift is initiated.

I'm thinking it may be the "Fast Off" feature that is causing the abrupt 2/1 shift and engine breaking. I don't think there is really any way for the car to know if you are approaching a corner or not. In a corner it can measure Gs, but not on the approach. So this could describe a quick stop as well.

That would mean a relatively slow stop with smooth throttle lift and easing into the brake should make for a smooth stop in D-Sport.

Finally, when I refer to smooth or abrupt, my context is from the perspective of an MT rather than an AT. The feel of shifts from PDK is more similar to SMG or MT, than to AT. That said, even our Lexus GX470 has a clunky shift on occasion - "automated transmissions" just don't always get things right - and neither do MT shifts for that matter.

[mstams]

Give it some time. Mine seems to have worked itself out.

[PersianGodFatha]

sounds very normal...I love it, and wouldnt have it any other way...Enjoy

[stevepow]

Originally Posted by mstams

Give it some time. Mine seems to have worked itself out.

I just went out to try to force this and I couldn't make the thing downshift hard in D-Sport nor M-Sport.

As soon as my wife gets in the car with me, I'm sure it will do it.

[ghb]

Originally Posted by stevepow

I just went out to try to force this and I couldn't make the thing downshift hard in D-Sport nor M-Sport.

As soon as my wife gets in the car with me, I'm sure it will do it.

Interesting that you brought that up - Sometimes the thumping doesn't happen even if I try to force it in every way that I can. However, sometimes it just happens (may be even several times consecutively). Very strange. I'll wait a little longer to see if the problem will work itself out, but the car already has over 3k miles (so if the problem will go away by itself, it would probably have happened by now).