ct14

Hello everyone, I have a very weird grinding noise in my Panamera S Hybrid under relatively light acceleration at speeds from 30-70 KPH more or less.

The noise is a pretty loud grinding noise, and you can feel vibrations through the seat. It looks like it's coming from the gearbox however the tachometer doesn't show any signs of it being the gearbox.

Clues:

• It happens in gears 2,3,4,5. Never seen it happening in either 1st gear or 6th,7th,8th gear.
• Changing gears manually with the paddle shifters doesn't stop the noise.
• However the slightest easing of the throttle makes the noise go away, back on throttle and everything is fine.
• No difference between modes (Sports / Sports Plus).
• Hybrid system works fine, the engagement/disengagement of the petrol engine and switching from electric to petrol mode are very smooth. (I would say this rules out the hybrid clutch)
• Underneath the car everything looks OK to the eye. No leaks, nothing loose, etc.

I am a bit lost with regards to this noise, we have no idea where it's coming from, and was hoping maybe someone has experienced this before. Any help would be extremely appreciated.

Thanks for taking the time to read my post, thanks in advanced, and may you have a great rest of your day

PS: Attached are two videos of the noise in question. I think it is very evident in the videos.

https://www.dropbox.com/scl/fi/8bp8h...83xyia95i&dl=0
https://www.dropbox.com/scl/fi/lcrjw...eqc1dqdwx&dl=0

Marcus13190

Strange noise. It's low frequency. I think is locate on drive shaft

ct14

Thanks for your reply Marcus

This is one thing we haven't checked yet. I was kinda thinking it was the rear differential, as today I had the noise happen while driving on battery power with the engine off, hence ruling out another suspect, the exhaust.

Tomorrow I'll check the drive shaft carefully from underneath.

Marcus13190

The drive shaft run when the car is electric drive

ct14

Checked the driveshaft and found nothing abnormal.

However yesterday while driving the car at some point the noise got pretty loud and it triggered a CEL.

After reading it with PIWIS3, it triggered the following code:

P309D00 - Separating clutch actuator - insufficient slip with open clutch

However, the hybrid system works well. The switch between electric mode and petrol engine is very smooth. How could the hybrid clutch cause this noise?

Marcus13190

Hi it's hydraulic clutch ?

ct14

Yes

Marcus13190

Perhaps you can try to refill oil

ct14

Yes, I bled the system once already, but nothing really changed. I am not even sure this is related to the clutch. As it is very smooth when switching from electric to petrol mode.

Marcus13190

There is this thread : HERE

ct14

In the end it was the driveshaft's carrier bearing. It was completely gone.

To anyone with similar symptoms, don't let code #P309D confuse you and lead you into a path of thinking it's related to the hybrid clutch/electric motor.... Code #P309D appears due to excessive vibration on driveshaft.

I never got code #P309D/check engine after replacing the driveshaft with a new one. And the car runs as good as new.

Marcus13190

Ok happy for you. My first idea it was good.