Question on O2 Sensor

hi i have a 2005 bmw 1 series 1.6 and the 02 lamda sensor showed up, bank 1 is replaced with a new one but but engine light still on, bank 2 has been checked too,

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This post was auto-generated based upon a question asked on our tech article page here: Pelican Technical Article: BMW 3 Series (E36) Oxygen Sensor Replacement

[Wayne 962]

The codes that the car gives you should tell you what bank is acting up. I would re-read the codes and see if you can tell which sensor is faulty from them.

- Wayne

[Manolito]

When you say that sensor number two has been checked, who checked it and how? On modern OBD II systems, the oxygen sensors must not only cycle and produce the proper maximum and minimum voltages, they must also respond quickly enough to work with the fuel injection system. If the tech did not check the response (which takes an oscilloscope or a high-end hand-held instrument) then the sensor may be getting old and slow. Any OBD II sensor with over 100k miles is running on borrowed time.