Ok i have a P0141 code on my Teg right now. I replaced the Back cat one brand new Denso oxygen sensor. I have a Bosh up front that has been replaced twice first one stock was bad the second new one got bad. I have tried replaceing the back, checking the fuses. I don't know what else to do. Can it be the damn Bosh having issues again? I recently had a map sensor issue that made me run hella rich. Can that be a issue with the Front one or no? Thanks for your help Brian

 

heater circuit of the o2 sensor. i suggest you get a wiring diagram

 

Try using an OEM one.