SIERRA SLT 2020 with 300 miles, Check engine went on and shutoff after 1 min. took it to the dealer and they told me the car fix it self . 800 miles light came back again, took it to autozone but the guy erased the code before reading it :( . got my self a test tool today, light is off, but I can read the same codes : U0146, U0100, U0101, and P25A2.