[lanii00]

Hello everyone,

I’ve had this issue for quite some time without finding a solution and I’d figure now is the time to fix it. I have replaced my pre-*** o2 sensors not exactly at the same time but they are both fairly new. And no I’m pretty sure they are located in the correct ********* as I know that is a possibility. I still get check engine lights on the car. Here are the codes I get

2C31 Lambda probe in front of catalytic converter, trimming control
2F7B Oil pressure switch, plausibility
29E1 Fuel mixture control 2

Here is the o2 sensor part number of the black wire o2 sensor that I replaced that I believed was the issue. OEM Part #: 11787558055

Why am I still getting codes ? Did I change the wrong O2 sensor? Is it Post *** O2 sensors ?

[Payam @ BMS]

That should be the primary O2 sensor for Bank 1. You could have swapped the wrong O2 sensor more than likely.

[lanii00]

Are you referring to the grey wire one is th bad O2? This part #: 11787558087?

[lanii00]

Could this be due to the amount of E85 vs what the tune reads ?

[mj6234]

I had the trimming control code and it was the rear O2 on that bank.

I can't explain it exactly, but there is some sort of interaction between the primary and secondary where the DME validates the readings between the two. I spent a lot of time and money troubleshooting my issue (including replacing the primaries) and it was the secondary all along.

I also had some sort of aging code for the secondary O2 sensor as well, which you don't appear to have.

[lanii00]

By secondary, do you mean post cats? Do you have part numbers by chance? Would this be on the outer ********* I’m guessing?

[RSicks]

Originally Posted by mj6234

I had the trimming control code and it was the rear O2 on that bank.

I can't explain it exactly, but there is some sort of interaction between the primary and secondary where the DME validates the readings between the two. I spent a lot of time and money troubleshooting my issue (including replacing the primaries) and it was the secondary all along.

I also had some sort of aging code for the secondary O2 sensor as well, which you don't appear to have.

I had the same thing, secondary O2 cause the code and cleared once I replaced it.

[lanii00]

Thank you! I will go ahead and buy that O2 sensor

[AZN54]

I had something very similar on bank 2. Replaced pre-*** o2, code remained. Replaced post-*** and cleared it up.

Make sure you reset adaptations after.

[lanii00]

Update: Took a while to do this, but changed the secondary O2 and no more codes ! Thank you all !