Hi there,

This is my first post and my first BMW. I had my SES light come on and the code read P1418, secondary air injection pump sensor. So I checked the pump and all related areas and found the pump to be bad. I replaced it myself with a used pump and that one works. It has no noticeable leaks or problems so I reset the computer. After driving it for 40 some miles the light came back on. I took it to a mechanic and he said that code 1418 is still there plus 281C (Bit serial interface signal) and 27C3 (thermal oil level sensor). The mechanic mentioned that those 2 extra codes could be related to the secondary air pump but it also could be the Mass Air Flow sensor. I want to be able to do this myself, I love working on cars and this is my first european one. So if anyone could help me, I need to fix this to pass my emissions and also not spend a fortune on having someone else fix something that I could do for less while also learning about my car. Thanks so much in advance!