2010 BMW 650i E63 Catalytic Converter fail code

[mmakabeh]

2010 BMW 6 Series 160K miles

Hi,
My engine light is on.
Fail message :
bank 1 and bank 2 readings bad
- replaced all 4 O2 sensors same fail codes ?
Also once in while maybe 1,2 a month my car smokes blue smoke for 20 seconds and stops
Specially if I reset the error codes.
Please advise.

[Timm]

Changing Lambda sensors against a mixture error is a bit like changing the temperature sensor when the engine overheats - you are treating the symptom not the cause. Have a read of these:

https://www.meeknet.co.uk/E38/Diagnostics.htm

[jclausen]

Check the diaphragms on the valve covers for tears, check get the oil to 10w60 m oil. And when your pulling faults until you perform the correct diagnosis they are just information on what to do, oxygen sensor faults more times then not are only setting faults because there reacting to something up stream.

[Niheem]

Did u find out what was the problem