Cat code
 

Hi guys. I have a 99 4runner sr5 that has a check engine light. The obd scanner is reading a code saying 'catyletic converter operating below allowable threshhold'. The truck passed inspection like this somehow because I reset the light (however it still shoots the code when plugged into the emissions scanner), but the light only stays out for a day or 2. Anyone have any suggestions other than replacing the exhaust system? From what I've seen online so far it's big bucks and not an option for me right now. I tried b12 injector cleaner with no luck. Thanks!