so I was drivin down to VT last week from nova and with 2hrs 2 go my check engine light came on in my 05 scion tc w 65kmiles. i checkd the codes nd it said o2 sensor in the catalyst. After i got home later that week the light was still on so I took out the battery to see what it would do. the light went away and i have driven almost 50 miles since then and the lights still off. my question is do i still need a new o2 sensor? is my o2 sensor still broken even though the light is off or is it fine now? sorry for the novel

 

My answer would be get it to a shop where the can hook up a scanner and see if your o2 sensors are functioning like they should. Yeah you would have to pay for diag, But you would have your answer.

 

had the same problem last week with my cel.( rear o2 sensor) scanned the code and deleted it. have driven almost 400 miles since then and it has not come back on. was told to do a compression test.

just my 2 cents

 

Someone told you to do a compression test because you had a one-time rear O2 sensor CEL? There's some great advice..

 

well if in time you will need it but jus wait until the light comes back on again

 

the code prolly stored in the computer , take it to a shop and have them check it out

 

ok so if i run the codes now it should still be there if the o2 sensor still isnt working? ill do that hopefully tonite

 

On OBD2 vehicles, most codes will be stored in the ECU even after they go away. It's part of the design requirements for diagnostics to help troubleshoot problems that aren't consistent. So even if you aren't getting that CEL at the moment, it should still be stored in the ECU and viewable on an OBD2 scanner until it is cleared (with the scanner).