Code P0420

[X535dee]

Just my luck. CEL came on today. Done research and could be o2 sensors to bad cats. To start I'd rather replace o2 sensors. If you had to choose replacing 1 or 2 sensors rather than all which would you suggest? Not to many finds out there in the webs pertaining to this certain vehicle when I do a search. Help appreciated thanks!

[Dekero]

P0420 indicates the upstream O2 sensor.. I'd start by replacing it... And don't get a knock off... Bosch or BMW OEM. Worst case scenario get the BMW one as used from eBay if money is an issue.

Install, clear all codes with a BMW specific scan tool and drive it for a week and rescan to see what comes back

[X535dee]

Originally Posted by Dekero

P0420 indicates the upstream O2 sensor.. I'd start by replacing it... And don't get a knock off... Bosch or BMW OEM. Worst case scenario get the BMW one as used from eBay if money is an issue.

Install, clear all codes with a BMW specific scan tool and drive it for a week and rescan to see what comes back

Thank you Dekero. I'll take your advice. I've read so much since last night. Even looked up new DPF's which are hard to find btw. Go figure? Anyhow I cleared the CEL last night and have driven it today and had not come back on. I'll keep this thread updated as soon as anything changes.