sutherantear

2013 Chevy sonic LS SEDAN WITH 1.8L L4 FI: H - LUW - FLEX with 39094 miles
help my check engine light is on took it to autozone they said that I have a code 597 its either thermostat or heater core.
the check engine light was on before and after I put in a new battery.
I just put a new battery in it today the old one was leaking a little bit & had corrosive on the positive side I cleaned all of that off when I put in the new battery. It is not over heating, all fluids are fine, AC & Heater work fine, the cooling fan works fine. It's just this stupid check engine light stays on.
I do not have all that many miles on my car and I was reading on geotab under Troubleshooting Vehicle Fault Codes By Patterns. Troubleshooting Vehicle Fault Codes By Patterns
I was wondering if anyone has a clue as to what this code might be and how to get chevy to fix it?
I bought 2 sonics same on the same day same year & cars just one white for my daughter & one blue for me.
I still have these warranty left on my car..>
corrosion limited warranty is for 100,200 miles or expire date: 05/23/2019
powertrain limited warranty is for 100,200 miles or exp: 05/23/2018
emission select componet ltd wty is for 80,200 miles or exp: 05/23/2021
bumper to bumper limited warranty - that has expired end at 36,200 miles or 05/23/2016