E90 Push Button Start, No Crank
 

06 330xi with push button start. Disconnected the battery to do some work on the valvetrain.
Re-connected the battery and it cranked and cranked but no start. Turns out we unplugged what I think is the DME when trying to make room to get the valve cover off and on. Located in a white box just ahead of the winshield on the passenger side.

Plugged in the DME correctly and now the starter won't engage, as in it's not getting power sent to it. Tried disconnecting the battery overnight and retrying, but still same situation. Everything lights up just fine but starter doesn't turn.

I believe it's a computer issue due to the DME being unplugged rather than a bad starter.

Thoughts on what we try next?

Are you able to pull any codes? From what I've read in the past about this issue, it could be a blown fuse in the ECU box.