rxrom

iTrader: (2)

My 2000 trans am has had the check engine light on since I bought it last year. It was code p420 low efficiency catalic converter left bank. I tried clearing it but after 10 miles of driving the light alwas came back on.

Today while driving the light disappeared and so far isn't coming back. Can the computer clear a code by itself?

rxrom

iTrader: (2)

I thought the light burnt out but it lits when the key is turned to on

GulfCoastWS6

If you have high flow cats or no cats it will trip.... other than that it could be the oxygen sensor or catalytic converter is bad. po420 is the back sensor reading i believe so the car should be running fine.

Snake_Skinner

iTrader: (12)

Yep happened when my cat went bad.

madmax4499

iTrader: (3)

yes, the light can reset after several drive cycles.