E90 oxygen sensor issues

[alijanjan 3]

Hi all

I used to get 2CA2 AND 2CA3 codes on my N46B20 e90 so I changed both pre cat oxygen sensors (it was a lot easier than I expected). 

Now with the new sensors I don't get those codes any more but I get couple of new codes. I'm getting 2C45 and 2C46. Also sometimes getting 2D11 and 2D12. Never used to get these codes before replacing the sensors 

While I was replacing the pre cat sensors, I unplugged the post cat ones and gave the plugs a clean with contact cleaner 
The new sensors were Bosch ones
Anyone had similar issues? Any help is appropriated

Thanks 

[B.M.W Ltd 950]

99.9% of the time 02 sensor fault codes are triggered by over fueling or running lean and not a sensor fault. They are the result... not the cause. The most common causes on your engine type is unmetered air (air leaks) in the manifold or crankcase breather system. Correct diagnosis is the key to repairing these faults. Using the wrong type of scanner can lead you down the wrong and expensive repair road.

[alijanjan 3]

On 12/24/2018 at 4:18 AM, B.M.W Ltd said:

99.9% of the time 02 sensor fault codes are triggered by over fueling or running lean and not a sensor fault. They are the result... not the cause. The most common causes on your engine type is unmetered air (air leaks) in the manifold or crankcase breather system. Correct diagnosis is the key to repairing these faults. Using the wrong type of scanner can lead you down the wrong and expensive repair road.

Thanks for the reply Glenn

I've looked and cannot find any obvious leak, unless it's the CCV. I've checked the CCV hoses and all seem intact ( as far as I can see without removing the intake manifold). Should I be looking at replacing the CCV kit? The car has done 150k

The engine runs very smooth however, cold and warm

 

Edited December 24, 2018 by alijanjan

[alijanjan 3]

So the oxygen sensor codes have all magically disappeared 

I'm thinking maybe to do with the adaptation as I couldn't reset them after installing the new sensors 

I have driven the car around 2k since the last reset and they have not come back yet

 

[Calin Pavel 0]

On 12/23/2018 at 1:46 PM, alijanjan said:

Hi all

I used to get 2CA2 AND 2CA3 codes on my N46B20 e90 so I changed both pre cat oxygen sensors (it was a lot easier than I expected). 

Now with the new sensors I don't get those codes any more but I get couple of new codes. I'm getting 2C45 and 2C46. Also sometimes getting 2D11 and 2D12. Never used to get these codes before replacing the sensors 

While I was replacing the pre cat sensors, I unplugged the post cat ones and gave the plugs a clean with contact cleaner 
The new sensors were Bosch ones
Anyone had similar issues? Any help is appropriated

Thanks 

Hello, 

I have the same issue with my E90, 318i and I can't figure out where is the air leak coming from, did you managed to find the problem?

[Sniffburger1974 0]

On 6/11/2019 at 9:00 AM, Calin Pavel said:

Hello, 

I have the same issue with my E90, 318i and I can't figure out where is the air leak coming from, did you managed to find the problem?

Hey all, 

I have the same problem as the original post but wasn't sure if to change the O2 sensors or look for leaks.  I only have 1 pre and 1 post sensor as it's the 2.0ll petrol.  Does this mean I have only 1 bank and not 2 banks? 

[noel1119 0]

Hello! I got the same issues with my car. E91 320i N46B20B, o2 sensor bank 1 sensor 1 is fault that say the code reader, but i changed already twice. Anybody got any ideas what is the problem with my car?