UPDATE: I finally got the car into the dealer with the fault, and the ECU reads that there is a Throttle Valve Control Module fault. The tech reset all codes and sent me home, to report if the fault returns.

Anyone have any experience with Throttle Valve module fault? I assume its just a plastic unit mounted somewhere. Anyone replace this part before?

 

RESOLVED
It was the throttle body/e-gas valve that failed, or was failing. Installation was very easy, remove the airbox, unplug the throttle body, remove 4 e-torx fasteners, replace gasket and install new part and reassemble. 20 minutes tops.

The X51 uses the same 82mm throttle body as the GT3 and, it seems, some Cayennes. Part #s are as follows: TB - 997-605-116-01 Gasket - 997-110-319-40

Throttle body is about $325.00 online for "genuine Porsche" and I found OEM Bosch for about $25 less. FWIW the original part that come off my car was clearly marked Bosch, so I would not be afraid to just save the $25 and get the OEM.

Thanks for all the help and advice guys. Happy to have the car at 100% again.

 

Glad you're up and running again. Was that you I met at C&C a few weeks ago with the M5? I was with my son in the Atlas Gray C2S.

 

Yes, that was me. Hope to see you out there again this sunday!