2004 oxygen sensor - which one?
 

2004 MPV

Need to replace an o2 sensor, but not sure which part# it is - the sensor is in the front of the car - right behind the radiator - about a foot or so off the ground.

Here are the BOSCH part numbers for the 4 O2 sensors for the 2004 MPV-
15314 - "located in front manifold/exhaust pipe"
15708 - located in rear manifold / exhaust pipe"
15257 - "located in front manifold / exhaust pipe"
13596 - "located in rear mainfold / exhaust pipe"

I have been looking for online diagrams - can't find anything - HELP !!!