LEXUS RX 300 WARNING LIGHT

I Recently Had My Engine Relplaced In A Lexus. However Soon After Having The Engine Replaced My Engine Light Came Back On Again. I Took It...

What Does This Mean. And My Clock Reset To 1:oo Am Every Morning When I Start It Up

I Had The O2 Air Fuel Ratio Sensor Fixed. The Mechanic Said It Was The One That Failed. My Check Engine Light Went Off, But I Still Smells...