EGO O2 sensor 1 replacement
 

I have a check eng. light and the code came up 1221, which
I believe is EGO O2 sensor1 needing replacement. Is this a very
difficult job, and how can I turn off the "check eng" Light?
Thanks very much. It is a bmw 1994 325I

Typically, changing them is easy... What car is it for....

what year? the 318 or 325 (i.e., the I4 or the I6?)?

Thanks for the reply. It is a 94 bmw 325i.
sorry for not including that info

Replacing them is sometimes a major PITA due to the fact there is little room to access the O2 sensor plus they are quite often very tight. It's worth a try, but I would suggest having the correct socket etc........and a long breaker bar.