The speedo is driven by a gear on the differential, so... Yes, it could be related. I had the differential in an auto go on me - the center shaft (pinion shaft?) slid out of one side of the differential housing, swung around and ejected the speedo gear from the tranny. I was driving along doing about 60 mph and I hear this POP and my speedo drops to 0. :?
On the other hand, it could purely be a problem with your speedo and/or cable - the VSS is part of the gauge cluster.
I was wrong, I assumed it was the VSS, but it's code 43. I thought that was O2 sensor, but apparently it's fuel supply system?
Then I look at the troubleshooting for it and it's O2 sensor after all! Something must have come undone when I was moving stuff around/washing the bay.