I have a 2005 Bmw 525i with the 2.5l m54 engine. I'm trying to figure out what's causing the code. It's referring to o2 sensor bank 2 sensor 1. But I changed all the sensors. Could a vacuum leak cause the code? When I run the engine & when I turn the engine off I hear the engine sounds like gasping/sucking air. My check engine light is on.

 

What is the PXXXX code that's associated with the 28E7 code?

 

how do I see that? I just got the code from inpa.

 

You can use a regular OBD reader / scanner. There are a number of PXXXX codes associated with the 28E7 BMW code, all of them pointing to different things.