toma nova

Twice in the last week, my PDK has downshifted randomly while cruising under constant throttle. I think both times were 4-3 going around 40mph on suburban roads. Normal mode, not Sport. Not accelerating, just steady speed.

I have about 10k miles on new fluid when the distance sensor was replaced and the PDK rebuilt.

Thoughts?

bldn10

Cruise control on? If so, a slight incline might cause a down shift just to maintain speed. I really don't like how the PDK works w/ cruise control. Say I'm cruising at 75 and need to slow a bit so I tap the brake and let it drop a few MPH. Then hit Resume and BAM - downshift and more acceleration than necessary. Also, if I'm cruising and want to lower the set speed w/ the stalk - pull it a few times and BAM - downshift and it seems to not know what to do.

toma nova

I was not using cruise control when these downshifts happened.

I fear that I will need to wade into the 997 PDK mega-thread again.

TMc993

I don't see two random downshifts as a problem, particularly if you are driving in Normal mode. I find that my PDK (2014 Cayman) is prone to a lot more up and downshifting when I drive in Normal mode than in Sport mode, particularly when I am cruising at speeds that hover around the shift point for the PDK. At 45 MPH in Normal, the slightest change in pressure on the accelerator or road gradient will precipitate PDK "hunting" the "right" gear and shifting down or up as the case may be. I call it "Buick Mode" because, in Normal, it hunts gears like a Buick. My solution is to keep the PDK in normal mode until it is properly warmed up, then put it in Sport. I don't think you have anything to worry about unless you get an increasing number of the random shifts at inappropriate times. Hope this helps.

Kitc2246

As stated in Normal the PDK will upshift to a very high gear for emissions and MPG. It doesn't take much to case a downshift. Sport will keep it in a lower gear with higher rpms.

toma nova

Thanks for the thoughts about Normal. The other variable is me: I have not driven the Boxster in about a month and have mostly been driving our new Polestar 2. The EV driving sensation is completely different than the Boxster so that likely adds to my perception of the PDK shifting.

BTW, instant torque (526 lb-ft) is intoxicating!

Ernest72

Likely normal. Even in normal with my tune which is better, the PDK can still get to 6th gear by 35 mph if I drive like grandma.

Buck_Turgidson

When I first got mine I was a little confused by the coasting function which isn't very compatible with my driving style at low speeds. The idle back into gear jump makes for a jerky ride so I always switch off the stop start mode now.
Are you certain it's down shifting and not re-engaging after coasting?