New car battery: how long till the computer is good on a Subaru

I have 2 more days to get my 2011 Subaru inspected. This morning 8 a.m. I found the battery was dead dead dead. Called AAA and got a new battery put in, called the garage. He said I have to drive it around a few days (!) so the computer will turn on and gather information, it won’t pass inspection till then. Well, I’ll be dipped. I never knew about this.

So just drive around for a while? How long? How fast? I’ve read complicated formulas for stop and go driving (I really don’t do highways - I can go 50 MPH after morning traffic for a few minutes down the road.)

Son of a beeyotch.

GM says about 100 miles

You will need a cheap OBD II scan tool to see when the emissions status changes to ‘ready’. Unless you just want to pray and go to the inspection. I’m not sure I understand “I really don’t do highways”. You don’t have anywhere near you with a speed limit that high?

Here’s what Subaru apparently says about getting the readiness set in the shortest time (lifted from another site, can’t vouch for accuracy):

My mother drove for 50 years, and never went over 25. Some people wouldn’t know how to get on/off a highway, or how to drive on one. Good thing they stay off.