Need help figuring this out - FIXED (code 0274A)

[VictorH]

2009 E90 M3
90,050 miles
Plugs have 27,000 miles on them.

Just had my passenger side throttle actuator replaced two weeks ago, but I'm getting an SES light that I don't think is related.
On the iCarly app, I'm getting "Failure Detection, cyl 2 00274A" No other codes with this one.

Engine runs fine, in fact I was at Road Atlanta last weekend and had no issues at all. While there I changed out the cylinder number 2 coil (passenger side second from the front, right?) with another coil from another cylinder, cleared code and 20 min later it's back. Then replaced cylinder 2 coil with brand new one, cleared code, it's back after about 20 minutes. No issues with starting, driving or otherwise how the motor runs.

Does anyone know what this code is and how do I figure out what's going on. Do I change that plug or it this some sort of sensor problem? Thanks

[BPMSport]

274A - Oxygen sensor pump current calibration error before cat. converter, bank 1.

Makes sense that playing with cylinder 2 yielded the same result.

[VictorH]

Thank you, that helps a bit.
So, do I change the oxygen sensors (pre-cat)? Why would cylinder 2 be noted instead of the passenger side bank, for a Oxygen sensor problem?

I have your tune (stage 2) with primary cat delete (test pipes).

[VictorH]

Problem fixed, thank you. Replaced pre-cat O2 sensor on the passenger side, cleared the code and all is good again (now almost 1,000 miles later).
Plan to replace driver's side too since it's just as old as the one that failed.