so i just replaced o2 primary sensor due to trouble code. now i am getting both p0134 and p2251 codes. are they related to a/f sensor? if so, where is the air fuel sensor located? please help, my car is running poor and very low gas mileage. thanks in advance

 

nevermind, i just replaced all 3 sensors and no more check engine light. so easy to do, took 30min for 3 sensors, not bad.

 

Which 3 sensors did you replaced?

 

Its the top rear o2 ( air fuel ) sensor . I recommed a pcm update as well. 2251, 134,and 2195
Are basicly the same

 

what is a pcm update? I have the same codes