Hi, HAF. My engine light is on. The code given is p0420. I was searching and I believe is something related to the optus census or an oxygen censor. Can any one help me out. Send some picture if possible. Thankyou

 

P0420 is "catalyst system efficiency below threshold". This means the rear O2 sensor performance is not aligned w/ expected performance, usually frequent O2 voltage changes aligned w/ primary (upstream of converter) voltage performance. You need an advanced OBD2 scanner to monitor the O2 sensor performance to know if problem is confirmed.

Some have had luck w/ chemical additions to gasoline and removal/washing. Check videos by Scotty Kilmer on youtube on this subject.

There are aftermarket catalytic converters available, but reports are uneven on their performance. Some give glowing reports, others repeat of P0420 in short time. Brands to check are Eastern, Bosal which seem to be better quality. I bought an Eastern for a 99 Subaru w/ P0420 and it worked for 1.5 yrs before P0420 returned again.

good luck