Ran out of gas, check engine light is on with P0420 code. Could running out of gas cause CAT failure, or is more likely to be the 02 sensors? Photo of home diagnostic posted. Thanks for your help! -Matt
Sometimes it takes as much as three gallons of gas to get things working normally again... Also do the codes come back right away after you clear 'em? Or does it take a while?
That will happen to every Prius that runs out of gas. Happened to me. Add gas, clear code, it will not come back.