2015 Impreza with 2 error codes

My check engine light came on yesterday and our local mechanic checked the codes for me this morning: P000B and U0073.

I had an oil change by Jiffy Lube 2 months ago and don't drive more than ~1k miles a month. Between the recent oil change and the combo of codes, I'm guessing I have an electrical problem? Can anyone equip me with insights/ theories as I prepare to reach out to my local Subaru mechanics/ dealers? My local mechanic says the chain engine is beyond him and I probably want to go dealer.

Last week happens to be the longest it sat in our garage (in MA) because I got norovirus, so it didn't run for 6 days, then the check engine light came on when it ran again yesterday.