P3000 code, help assessing the issue

Hi all,

09 prius, 180k miles

My car sat for about 9 days recently, when I came back the battery was dead. This is typical when I leave the car sitting for a week ish, and it does even quicker when it’s really cold. Pretty sure there’s some type of phantom drain on the 12v. The 12v is new replaced a few months ago.

the car sat 9 days and I jumped it with a remote started I always have on hand. It turned on and after about 30 seconds red triangle came on. Read the code with Dr Prius and P3000 came up. I was unsure what to do. I figured it had something to do with the car having been dead, and I think I read on here before about you being able to clear it and keep going, so I did that. That was two days ago. Since then drove around 6-700 miles and today when I was coming to a stop at a red light, the code came on again. Again I cleared it and now I’ll see how long it lasts for again. But any ideas what’s going on?

Car is burning oil pretty good but I stay on top of that. Getting around 38mpg and it’s winter in NY. Any one have any idea what’s going on based on this description? Attached is a screenshot I just took of Dr Prius. I got another 1k miles to drive in the next week or so, hopefully I can reset it again if that happens again.