Two brand new O2 sensors throw codes without leaving driveway.


Nov 6, 2016
Long Island, NY
Hey guys, have an interesting issue going on. I have an N54 with a DocRace ST kit. I recently did a full refresh on my mechatronic unit, and pulled my BimmerLife coils for the preferred Delphi's, as I felt no difference. Ever since I finished the tranny job, the precat bank 1 oxygen sensor has failed. My NTK first failed as I started filling the transmission following the mech unit job. Following that I ordered a Bosch O2 from FCP as Amazon is backed up preventing quick retrieval of an NTK, and that one failed within a drive down the block. I then found another Bosch sensor which popped on second startup without driving the car. Bank 2 is totally perfect, pinned at 14.7. The AFR first sits around that 14.7 mark, then quickly rolls away. I have both postcat sensors disconnected. I have no other codes, besides a power management relay code which I only had when the battery died on me, and never came back after clearing codes. So all I have is function/temperature of Bank 1 precat sensor. I am totally clueless at this point what could cause such, so I thought I'd ask you guys. Any help is greatly appreciated !