Hi, Hoping for a little advise... 2005 Honda Pilot threw a 0420 code, used cat cleaner and seemed to work which is crazy lol The Catalyst monitor DID clear! :-) BUT the 02 Monitor will not complete? I used the spacers on B1- Downstream, I drove ALL advised drive cycles over and over again now 400+ miles and nothing... all monitors clear except 02's even the evap cleared... Any help would be awesome.. Should I try changing sensors? If bad though wouldn't it throw a 02 code? PLEASE HELP ? :-) Thanks

 

Remove the spacer and try again.

 

hi I forgot to mention in the first post. I ran it at first without the spacer after using cat cleaner.. the cat cleaner seemed to work as the Catalyst monitor cleared but the O2 sensor monitor never did clear. I was told that was the easiest one to clear so I was scratching my head.... but then after about 200 miles it through a pending 420 code so I put the spacer in.. now Catalyst clears and stays clear but same thing O2 sensor monitor never has cleared... do you think O2 sensor could be bad? I was told that if it were it would throw a code..thanks very much

 

I think your catalytic converter is bad and needs to be replaced. The spacer is probably the reason your o2 won't clear. Probably pending on a slow response because of the spacer.