So I just replaced my bank 2 sensor 1 o2 and now I'm getting this code. I'm wondering if it's not just because it's an after market Bosch O2. The sensors are the same size although the ports on the new one are on the top and the old one had them on the side. The wiring matches up. I haven't had a change to take a multi meter to it yet. Any thoughts gents?

 

i'm having the same problem. all new o2 sensors first i got 135 and 155 codes then replaced both upstream sensors and now i have just the 155 code. ?????? i am so lost at this point i hope something comes from this!

 

Fixed it. Get yourself some electrical parts cleaner and q-tip. Pull the O2 plugs and clean them. Fixed my issue.

 

I erased the codes about 3 days ago and it still hasn't come back. So we'll see what happens. If it come back then I'll try cleaning everything up