2c7e Lambda probe Error

crasher381 · 11-07-2011, 08:40 AM

Currently I have a 2008 335i with the following mods:

jb4
ets intercooler
ar design catted down pipes
ae cat back exhaust
bms dci

The car seemed to just not be running 100%, so I started to check and see if I could notice an difference while idling and reviing up the engine. I didn't really notice anything at first. But once I quicly revved up the engine to about 4000-5000 rpm I go a lot of white smoke out of the exhaust. I was able to reproduce this several times. I checked the error codes int he computer and the only one listed was:

2c7e Lambda probe behind catalytic converter, trimming control

From what I gather this is related to the Bank 1 o2 sensor after the catalytic converter. I then ran INPA and checked them and Bank 1 o2 sensor does seem to be having issues, but I am not sure what the readings should be. Attached is a picture of the readings I got from IPNA.

The bank 1 after cat o2 shows very low voltage, however when I rev up it does go up, but on idle it stays about 0.00 to 0.07 voltage. Whereas the bank 2 one stays about .6 to .7 voltage.

Does anyone know for sure if that means that the bank 1 o2 sensor is bad and that I need to replace it? Any help or insight would be awesome. Thank you.

bmbob · 07-19-2012, 11:35 AM

Did you find any solution to this? I am getting the same code.
Not sure if you replaced bank 1 02 after cat, but if so, did it fix it?
Are you getting bad mileage?

EJ_3 · 07-19-2012, 10:01 PM

Make sure you have the correct o2 sensor in the right pipe. The one with the grey wire should be going into the pipe in the passenger side.

edmfperez · 06-17-2017, 08:02 PM

Hey there...sorry to ressurect the thread but I’m having similar issues with my car. I got the 2C7E error for the bank 1 post cat o2 sensor failure even after replacing the sensor.

Does anyone Have a clue on to what else the issue could be?

teggei2 · 05-27-2018, 09:46 PM

Quote:

Originally Posted by edmfperez

Hey there...sorry to ressurect the thread but I’m having similar issues with my car. I got the 2C7E error for the bank 1 post cat o2 sensor failure even after replacing the sensor.

Does anyone Have a clue on to what else the issue could be?

Exhaust leaks can cause this. Another guy replaced his gaskets and it went away.

11-07-2011, 08:40 AM	#1
crasher381 Enlisted Member 5 Rep 32 Posts Drives: 2008 335i E90 Join Date: Aug 2010 Location: Ocala,FL iTrader: (2)	2c7e Lambda probe Error Currently I have a 2008 335i with the following mods: jb4 ets intercooler ar design catted down pipes ae cat back exhaust bms dci The car seemed to just not be running 100%, so I started to check and see if I could notice an difference while idling and reviing up the engine. I didn't really notice anything at first. But once I quicly revved up the engine to about 4000-5000 rpm I go a lot of white smoke out of the exhaust. I was able to reproduce this several times. I checked the error codes int he computer and the only one listed was: 2c7e Lambda probe behind catalytic converter, trimming control From what I gather this is related to the Bank 1 o2 sensor after the catalytic converter. I then ran INPA and checked them and Bank 1 o2 sensor does seem to be having issues, but I am not sure what the readings should be. Attached is a picture of the readings I got from IPNA. The bank 1 after cat o2 shows very low voltage, however when I rev up it does go up, but on idle it stays about 0.00 to 0.07 voltage. Whereas the bank 2 one stays about .6 to .7 voltage. Does anyone know for sure if that means that the bank 1 o2 sensor is bad and that I need to replace it? Any help or insight would be awesome. Thank you. Last edited by crasher381; 11-07-2011 at 08:41 AM.. Reason: Link broken
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07-19-2012, 11:35 AM	#2
bmbob Private First Class 268 Rep 197 Posts Drives: 18' C63S, 15' M4 Join Date: Jan 2012 Location: Calgary iTrader: (0) Garage List 2021 BMW M4 Competi ... [9.50] 2018 Mercedes C63S [8.00]	Did you find any solution to this? I am getting the same code. Not sure if you replaced bank 1 02 after cat, but if so, did it fix it? Are you getting bad mileage?
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07-19-2012, 10:01 PM	#3
EJ_3 Colonel 371 Rep 2,838 Posts Drives: e92 335i, e34 525i & e60 530i Join Date: Aug 2011 Location: N Las Vegas iTrader: (13) Garage List 2007 BMW 335i [8.34] 2016 Ram 1500 Sport [8.00] 1994 BMW 525i [10.00] 2007 BMW 530i [8.66]	Make sure you have the correct o2 sensor in the right pipe. The one with the grey wire should be going into the pipe in the passenger side. __________________ click here for mods
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06-17-2017, 08:02 PM	#4
edmfperez breaks things 13 Rep 47 Posts Drives: 2007 335i Montegoblau 6MT Join Date: Feb 2015 Location: Austin, TX iTrader: (0)	Hey there...sorry to ressurect the thread but I’m having similar issues with my car. I got the 2C7E error for the bank 1 post cat o2 sensor failure even after replacing the sensor. Does anyone Have a clue on to what else the issue could be?
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