Gen2 Fault Code: P1F40

[sdiori]

Anyone familiar with this code?

Background:

Brentune flashed prior to new exhaust.

New, full exhaust done by local shop.

Servo buddy installed. At pick up, shop told me they thought my servo buddy was defective because it caused an engine code.

After emailing BT, they recommended scanning with the flasher tool.

Flasher tool displayed the fault code above.

Cleared it via the flasher tool, code returned.

Quick call w/ my local BMW dealer didn't drum up any new info...the service adviser was unfamiliar with it.

A quick Google search also yielded to answers.

I have an appt next week, but I figured I'd ask here.

I suspect that either the servo buddy is actually defective or the shop may have crossed the O2 sensors.

Thanks for your help!