Austin997.2

I was driving today from a cold start for a couple of minutes. I gave the car gas and it revved higher but the car acted like it was in neutral and stopped accelerating. I was driving with the car in D, not shifting manually and then tried to fix the problem by trying to shift manually and that did not work so back to D and it still did not work. I could not get it to accelerate in any PDK transmission option so I pulled over. It basically acted like it was in neutral when I was in drive.

I then restarted the car and it drove fine after that. Today was a cold day for Austin, around 39F, so maybe that could be part of the equation? Called the dealership and they said to bring it in if it happens again.

Any help would be appreciated.

semicycler

Could be something as simple as old or low automatic transmission fluid. Any leaks under the car? When was the last trans flush?

Austin997.2

I have not noticed any leaks. Not sure if it has had a trans flush, the car has 31.7k miles on it and I've had it for 3.5k miles.

Wayne Smith

PDK flush is scheduled at 60K.

ADias

Yes, but it should be also done, every 4-5 years, whichever is less (both transmission and separate clutches' oil).

StormRune

One possibility is that something was holding your brake pedal down somewhat. I think this can prevent the tranny from engaging. Maybe the floor mat worked its way up onto the brake?

There is one other more unusual possibility I accidentally discovered. One time I did some work that required removing the air box and I had from some reason unplugged the electrical connector on the right rear vacuum switch that controls the resonator flap in the airbox. After the work was complete everything initially seemed fine. I had no problems on my first drive out, but when I went to start the car to come back home I couldn't get the car in gear and I got a PDK transmission failure warning on the instrument panel display. Did you look for any error message in the area of the odometer, it would have been displayed in red?

This seemed just too coincidental since I had just done the work in the back. I looked around in the engine compartment and checked everything I had touched and found the connector unplugged. I plugged it back in and everything worked fine from then on. Even though the association seems really odd, that seems to have been the problem. I know you recently were rear-ended. Did anyone possibly unplug the electrical connector for resonator vacuum switch as part of the examination? Maybe it isn't snugly plugged in? I'd guess this is far-fetched but just in case.

ADias

Great info!

Austin997.2

Hi, I don't believe it was either of those circumstances, the repair shop has only taken pictures of the outside and have not touched it. I have a warranty on it through Carmax, so I might bring it in tomorrow to the Porsche a Dealership to have them check it.

By getting rear ended, would it be a possibility something damaged the trans?

Thanks for the help again. Bad car week for me so far

Robocop305

I had the PDK transmission failure light several times and the car would not move from a stop. Apparently, it was related to some electrical issues due to a faulty battery. I changed the battery a year ago and problem solved.

Wayne Smith

True ... that! But there has been a lot of confusion by dealers if they have the correct oil, etc. I get the feeling that the dealer network has little to no experience with the PDK pertaining to it's repair.

Wayne Smith

Amazing what a marginal battery can cause. Most of these sensors are designed to operate with between 10 and 30 vdc. If the battery drops below 10 the all bets are off.

RobC4sX51

Really? My service book only indicates "on miles" not years. I did my clutch oil @ 40k (recommended at 60k) and will probably do the PDK trans oil at 60-75k miles (recommended at 100k) but I think it only makes me feel better as I know most manufactures (VW dsg) say lifetime. We drive them hard so we take better care than book says😊

Sorry for your Pdk issue. I hope it was a onetime thing but probably not. Dealer should be able to diagnos and do any software upgrades.

steve0827

I had this issue too when it was very cold out! Did you have a reduced engine power light come on?

Austin997.2

no lights that I can remember

ADias

What is the condition of your battery?