Oxygen Sensor 7-12 Cylinder not working

[Pufhead]

Hello

I have just replaced both Oxygen sensor on my 850 after both of them being broken and having engine problems as the engine is not running as clean as it should
and after being on diagnose test at a local BMW work shop they found that the Oxygen sensor on bank 7-12 still wont work after getting brand new ones
unfortunately they did not have any more time to check it out and try to locate the problem

what i have tested out so far my self
i have tested the cable from the Oxygen sensor to the DME unit and that is whole as far as i can see as i get signal on all the cables running to the Oxygen sensor
i all so tested out just swapping the DME units for 1-6 whit 7-12 Cylinder whit out no possessive results on that

[peake]

Oxygen sensors shall be changed every 80.000 km according to BMW repair handbook. Dependent on manufacturer/quality the sensor can be broken from the start. One way to find out is to switch the sensors with each other and see if the fault follows. BTW I changed my sensors (Bosch) a couple of months ago and there is a noticeable change, less gasoline smell in the exhaust and lower gas consumption when driving.