Hyundai downhill spiral

I recently had the clutch in my '99 Hyundai Accent replaced (105K miles). When I went to pick it up, the battery had died. It seemed to be the original battery, so I replaced that and the battery terminals too. So the car started and was moving fine, but then I noticed the speedometer wasn’t working. Then, after the first time I stopped the engine following the battery replacement (to put in some gas), the Check Engine light went on. Is there any relationship between these problems? Did the clutch replacement cause any of the subsequent problems? Any suggestions?

They could be related. It sounds like someone forgot to connect a wire connector for the speed sensor when reinstalling the transmission. This can also set the Check Engine Light.
Back to the shop and have them recheck their work.

If the shop that did the transmission does not find a problem, or if the light does not go out within a few days after they reconnect things. You need to have the codes read. Some places will read them for FREE. Try Autozone or Advanced Auto Parts. Get the exact code (like P0123) not just their translation into English and post it back here.

many thanks for the suggestions. will keep posted.

found the wire for the speed sensor, got it reconnected to the transmission, and the speedometer got back up and the CEL went off.
again, thanks to y’all for the help.