My 2013 E92 M3 is giving the following 2 faults after I completed a spark plug change (intake plenum removed):
1) 274B DME oxygen sensor pump current calibration error before cat converter bank 2.
2) 27B0 DME secondary air system flow rate bank 1
I verified the secondary air pump (SAP) is working by feeling the vacuum pull on cold start, but I can't verify the air pump check valves (ACV) are opened without more invasive investigation.
What are your thoughts? Do you guys think these two faults are related to the O2 sensor even though they're different banks? Do you think these faults coming right after a spark plug change are coincidental?
I think a quick chicken test would be to swap the O2 sensors and see if the faults follow the sensors...but would really like to avoid the SAP and ACV...
Thanks in advance!