2c7c 2c7b Codes on single turbo.

JimboFresh206

Sergeant
Jan 29, 2018
289
152
0
Ride
335/635/535/533/633
New rear 02's are still throwing this code.

"Oxygen sensor after catalytic converter: Signal"

throws it on both banks, but mainly bank 2.

I know someone on here had a similar issues and it was that bank 1 and 2 were switched in the Down pipe, and not at the harness connector.

harness, and sensors both DMM fine... My tuner (jake.h) tried a couple revisions but its still cropping up, so i think its clearly on my end.

Unplugging them and cleaning the contacts with de-oxit worked for about a week... but I think that was just a placebo/FUD because new bosch rears are throwing the same code.
 

WOT808

Specialist
Aug 7, 2017
81
56
25
Ride
E90 335i
I have a Speedtech kit and have been getting those codes since shortly after install (5 months ago). I haven't reached out to Jeff because I haven't had time to check my hardware. I was thinking my o2s got dirty during the install.

I have PI and running pump e85.

The codes seem to pop up shortly after pulls but rarely during cruise.
 

JimboFresh206

Sergeant
Jan 29, 2018
289
152
0
Ride
335/635/535/533/633
same, and same...

think we have the banks switched in the DP?

it seems to be killing my gas mileage, but my logs looks normal
 

WOT808

Specialist
Aug 7, 2017
81
56
25
Ride
E90 335i
same, and same...

think we have the banks switched in the DP?

it seems to be killing my gas mileage, but my logs looks normal

Maybe. Would bank 1 o2 need to be in the bung closest to the flex joint on the DP?
I was thinking the order of the sensors didn't matter because exhaust from both banks are no longer separate after the turbo.
 

veer90

Lieutenant
Nov 16, 2016
1,000
774
0
West Nyack, NY
Ride
e90 335i 6MT
That's what I'm wondering, there's 1 post from @veer90 in the ADV sensor thread, and he was having issues because of that, but that was with JB4 iirc.

It wasn't JB4 related, and I never had ADVs... not sure what you're referring to.

Do you have single rear O2 enabled? If so bank 2 will throw signal code since only bank 1 rear is being used.
 
  • Like
Reactions: JimboFresh206

JimboFresh206

Sergeant
Jan 29, 2018
289
152
0
Ride
335/635/535/533/633
It was just a post you made in the ADV vs. NTK Thread :)

These are the options I have in MHD, do I need to ask my tuner to enable that?
29191
 

WOT808

Specialist
Aug 7, 2017
81
56
25
Ride
E90 335i
According to this FCP o2 listing , bank1 post cat o2 is wrapped in black sheath. I've heard the connector from bank 1 can't fit in bank 2's socket.
I took a peep under the car and the bank 1 o2 is in the bung closest to the DP flex joint.

Hard to believe that both of them went bad right after the single install.
 
  • Like
Reactions: JimboFresh206

JimboFresh206

Sergeant
Jan 29, 2018
289
152
0
Ride
335/635/535/533/633
@WOT808 Yeah having a tough time with that too since the new Bosch did the same thing. I have a set of ntk, aswell as a set of Walker rears I'm going to try out today.

It almost seems like a ground issue, or maybe our 02bungs are not in the flow path/the right depth?


@jyamona is that something (single rear 02) I need to ask jake.h to add to my flash?
 

d8rknight

Private
Jul 22, 2019
33
30
0
Tampa, FL
Ride
10' 335i , 15’ E400
I'm about to order this kit. Is this a common issue. I have to go find the FB post I read recently, but it was something along the lines of having one of the sensors codes out or something.
 
  • Like
Reactions: JimboFresh206

JimboFresh206

Sergeant
Jan 29, 2018
289
152
0
Ride
335/635/535/533/633
Nope, sorry forgot to update.

The bosch 02s I got from auto-zone had some issues, but a set of NTK's from rock-auto did the trick.

pretty sure i just got a set from autozone that had been dropped or something, they were missing the plastic caps when they arrived.
 
  • Like
Reactions: Blackarrow335i

WOT808

Specialist
Aug 7, 2017
81
56
25
Ride
E90 335i
Nope, sorry forgot to update.

The bosch 02s I got from auto-zone had some issues, but a set of NTK's from rock-auto did the trick.

pretty sure i just got a set from autozone that had been dropped or something, they were missing the plastic caps when they arrived.

What are the part numbers for the NTKs you got?