New to the aveo. Some issue/questions.

2008 Aveo sedan LS
auto 162,xxx miles

Recently picked up an Aveo from a co-worker. Seems like a decent car. No rust. Which is hard to find here in Minnesota. Its sluggish but maybe i can help it a little with fresh plugs/wires and an intake of some sort..

Anyway,
I know the tire topic has been beat to death on all forums. But i am going to buy winter tires here in a few days. Maybe a week away. It has aftermarket 14's. I picked up 4 15" steelies from a cobalt. I believe the stock 15" size is 185/55r15. Id like to go a little bigger/taller for ground clearance in the snow.
Any recommendations?
Would a 195/60r15 fit? The car does get loaded. at times the rear does sag some. Would rubbing be an issue?

Check engine light comes on and the car will run rough and won't shift to 4th gear.
Using the torque app and adapter the codes i get repeated are:
P0700
U0100
U0001
U0073
U0101

I clear the codes and the car runs fine. But they do come back after a while. Sometimes several times a day. Sometimes it takes a day or two.

I use my car for deliveries. This was kind of a forced buy as my cars brakes failed (no pedal pressure). And my coworker is letting me make payments as I have had a rough month.

Any help is greatly appreciated.
Thanks

When I buy snow tires, I usually just go with whatever is inexpensive. They're really all better than all season tires.

The U codes you got are transmission codes. This makes sense since the P0700 is a transmission code as well. Unfortunately, I'm not familiar real familiar with automatic transmissions.

Last year was my first time with snow/winter tires and i will never go back to all seasons in snow. I just got the cheap ones from discount tire. Had them on my focus. They made my car handie 6"+ with ease. I was out in almost 2 feet of snow with very little trouble.
How do these cars handle snow?
My other car is a focus zx3. 5 speed, no abs/traction control/etc.
Its currently undrivable due to no brakes (hydrologic system isn't working correctly).
But im use to a small car in snow. Just not this small lol.

Hopefully someone will chime in on the codes.
Thanks for the reply

These are primarily all CAN errors, and the first thing to check is the connectors and all wiring bundles to the ECU.