Pulled away from a stop light today and immediately lost all power and the idle was surging and throttle pedal was completely unresponsive, all the DSC, 4x4 and other lights were on. It was exactly like what's in this video:
After restarting the car a few times it finally was running normal. Then after pulling out of the parking lot it happened again. Restarted another 6-7 times and finally it was running okay and now the check engine light stayed on (but the 4x4, DSC, and other lights were off). It's driven fine since then but what I find odd is the only code is P110D which has to do with throttle position sensor and I wasn't aware that we would have one, being a drive by wire car. I also don't see many people with N54's ever mentioning this code. Anyone else familiar?

Attached is the OBD Fusion diagnostic report with freeze frame data (note I didn't have the engine running at the time that I created the report).

I suppose I can try unplugging and plugging back in the throttle body. I had it out in December when I blasted the intake valves and this same thing happened the first few starts of the engine after that but from my reading it sounded like that could be normal until the reset adaptations I did with ISTA+ took place.

 

I would have to assume there's a TPS on a DBW car since the ECU needs to know throttle position relative to other inputs. Others may be able to provide a definitive answer.

 

But the ecu is determining at any time where the throttle should be and moving it there itself. If it had a throttle cable I could see that it would have to measure to see where the throttle is, so my E30 had one. It could have a built in sensor to measure where it is in relation to where the stepper motor is trying to put it... that said, I’m just not finding much info out there for N54 engines along with this code.

 

Did you see this?
https://www.e90post.com/forums/showthread.php?t=909921

I would imagine the TPS is in the throttle body.
My 2004 GM with drive by wire had the same problem a few weeks ago and a new throttle body solved it.
It's only 215 on FCP for a TB

 

I did see that, thanks. That’s where I found the video I posted. I don’t think he had the same error code as me though. I could just get a throttle body but hate throwing money at things without knowing for sure they are broken.

 

Oh geesh, no wonder the video still looked familiar, duh.
Cleaning throttle body, checking wiring and grounds maybe?
The symptom descriptions for the TB on FCP look similar to yours.
The code itself points to the TB. My code had the same A and B out of range description except it was a P2135 for GM
I am shooting from the hip here with my limited experience