[NxTH]

Had a 200 cpi catted downpipe installed to replace my catless on 335i f30 AH3. I never had any codes or anything with bm3 while catless, but now with catted, I'm getting this:

"139001: Oxygen sensor after catalytic converter, from rich to lean: Delayed response"

I have stage 1, cat monitoring off, and the code manually blacklisted. It still comes back every 2 weeks while cruising over 80km/h. I believe it could be due to cold weather, but not certain.

What else needs to be done and why am I getting a code catted, and not catless? I also don't understand why BM3 suddenly isn't clearing the code since it is related to the cat.

I also got these previously:
12BE08, after cat, from lean to rich, slow response
12A308, after cat, from rich to lean, slow response

These I think got blocked by the blacklist function on BM3 since I haven't seen them again. The 139001 does pop up occasionally however.

[n55david]

Originally Posted by NxTH

Had a 200 cpi catted downpipe installed to replace my catless on 335i f30 AH3. I never had any codes or anything with bm3 while catless, but now with catted, I'm getting this:

"139001: Oxygen sensor after catalytic converter, from rich to lean: Delayed response"

I have stage 1, cat monitoring off, and the code manually blacklisted. It still comes back every 2 weeks while cruising over 80km/h. I believe it could be due to cold weather, but not certain.

What else needs to be done and why am I getting a code catted, and not catless? I also don't understand why BM3 suddenly isn't clearing the code since it is related to the cat.

I also got these previously:
12BE08, after cat, from lean to rich, slow response
12A308, after cat, from rich to lean, slow response

These I think got blocked by the blacklist function on BM3 since I haven't seen them again. The 139001 does pop up occasionally however.

Replace the 02 sensor, it's bad or damaged.

[yupetc]

Check your O2 install sequence. I've seen a similar code like that before on a B48 Mini Cooper S, turns out when they did the catless DP on that car, they've got bank 1 and bank 2 reversed. It was a pain in the arse trying to find out why; but eventually when I had ISTA+ plugged in and followed their troubleshooting test plans I caught the detailed instruction on which sensor goes to which bung and got that resolved.

Interestingly, when they had their DP installed wrong, they also had it dyno tuned, and with those errors they still pulled some good numbers. But eventually after the O2 sensors got swapped back, the CEL didn't come back after reset. That car was fun to drive; lightweight, nearly 260whp/300wtq, it's a blast.

[NxTH]

I ended up blacklisting the code successfully, but it was caused by a spacer.