P0101 is the code that I got from my failed smog check. Where is this located?

Check to see if the O2 sensor heater circuit is fused...as in a blown fuse... Some vehicles/Toyotas have these O2 sensor fuses ...

Unless you got a V-6 jammed in there , it's the rear-most sensor in the system......(yes , 1.8L 4cyl.)