Dear experts,
I got a trouble with my Panamera 2015, which is around 57kmiles. In a day, the car was parked in a flat surface, and I started the car and moved the gear to drive. But the car didn't move and was slightly shaking front and back when acc pedal was pressed. No error messages in the dash. I turned off the car and turned it on again, and then it worked normal. I have been testing the car for a week but couldn't reproduce the same issue again. After the failure, I scanned with iCarsoft, but couldn't find any error messages.
I read some other threads to talk about transmission rod sensor error, but in this case, my understanding is that "transmission fault" is displayed in the dash. Also if it's transmission error, I guess that it's behaving like a neutral and the car may not shake.
I checked brakes and parking brakes, but didn't find anything abnormal. The only thing which has recently changed was that I changed the battery DIY two weeks ago. It's not OEM battery but it was registered. In cranking the battery voltage is dropping to 11V when it is measured with multimeter, and it drops to 8.7V in ODB read. Can anyone give me any suggestion what I can check to find any clues?
Thank you so much in advance!

 

Your battery may be too small or not putting out what you need ? Have you serviced the PDK yet ?

 

Thank you for suggestion, Digs! While the battery is not OEM, I put the same spec of battery. While it's not certain if this is a battery issue or not, if battery is an issue or position sensor is an issue, I guess that transmission fault error should show up, but I didn't see that. I didn't have PDK service yet, and I would like to get it. As I couldn't reproduce failure for a week, I would like to investigate other possibilities before having PDK service.

 

I think that you have had a problem on hand brake. PDK problem without Fault code it's curious.

 

Perhaps the parking brake was on.

 

Thank you for your suggestions, Marcus and kippjones11!
I also suspected hand (or parking) brake, but below are what I found.
1. If I pedal gas with parking brake on, parking brake is automatically released.
2. If I pedal gas with parking brake on without safety belt locked, parking brake is not released but the dash warns me that parking brake is on.
So none of above was what I experienced.

I also checked parking brake with my iCarsoft. When I scanned PSM manually, I got below error code. I am not sure if it's real error or not, and iCarsoft may not be 100% compatible with Panamera. But nothing is shown in my dash as parking brake error. Cylinder air gap was measured in iCarsoft with 2.8mm for each side, which is slightly larger than spec, but it proves that the air gap is enough, so there is nothing stuck in my parking brake cylinder.
So it's still very puzzling. Is there any other suggestions which I can try? Or any clue for below parking brake message in iCarsoft?
Best!

 

You need erase your fault code first and see if it's come again

 

Thank you, Marcus13190!
I deleted the fault and had test drivings with multiple on and off. So far the fault doesn't show up yet. I may drive a few more days and check again if it shows up.

 

Now it's ok waity and see.

 

Just updating status for others. The same issue couldn't be reproduced more than two weeks. It's not conclusive, but hope that it was just one hickup.