2 warnings after installing a new radio

[Jomby15]

2008 GT convertible. I swapped out my radio today with an aftermarket from crutchfield. I disconnected the battery before I did any work on it. I removed the shaker 500, and then installed the head unit using all the recommended gear from crutchfield. When I started the car, the new radio worked fine. But I got 2 new messages. 1. Low tire pressure. 2. 0 miles to empty on my message center. (my fuel gauge says I have a 1/4 tank). My tires are fine, and there is enough gas. Is this because the battery was disconnected for 4 hours? Or is it because of some kind of wiring error i made with the radio? Will these problems resolve themselves, or am I going to have to do something?

 

[DieHarder]

2008 GT convertible. I swapped out my radio today with an aftermarket from crutchfield. I disconnected the battery before I did any work on it. I removed the shaker 500, and then installed the head unit using all the recommended gear from crutchfield. When I started the car, the new radio worked fine. But I got 2 new messages. 1. Low tire pressure. 2. 0 miles to empty on my message center. (my fuel gauge says I have a 1/4 tank). My tires are fine, and there is enough gas. Is this because the battery was disconnected for 4 hours? Or is it because of some kind of wiring error i made with the radio? Will these problems resolve themselves, or am I going to have to do something?

1. Do you have a code reader that you can use to clear codes? I'd try that first to see if the codes come back.
2. Wire brush and reconnect the battery connections.
3. Recheck your work. Did you remove and/or forget to reconnect any grounds?