SocomM4

iTrader: (2)

Code reader says possible problems ranged from loose connection to bad pcm.

so tried looking at the connections and checking them out. Cleared code, came back.

So just replaced it. But damnn 130 bucks for a damn A/f sensor?

Hope they gAve me the correct one and location at autozone.

Which is B2s1?

Turbonut

iTrader: (1)

You'll need upstream front O2 sensor, and yes the upstream sensors are expensive.
According to aftermarket catalog, both upstream sensors are the same.
OEM ($210/$151) has different part numbers (L&R), probably just different length of wiring.

SocomM4

iTrader: (2)

B2S1 location?

Turbonut

iTrader: (1)

See below:

SocomM4

iTrader: (2)

Derp. My bad . Good. So replaced last night and no cel.