can you should me were on the car are the oxgyen senors all 4 I don't know where on 2004 Cadillac DeVille

can I get a picture of where they are

Asked by for the 2004 Cadillac DeVille
why are you replacing them?? the chances of all 4 failing at the same time is like you getting hit by lightning in your living room.

what is the issue??

or could it be the mass air flow senor
ok, same question, what is the issue???
service engine soon light stays on
what is the code??

po171 and po174
Those codes tell you the sensors are working . diagnose the CAUSE before replacing parts .
1 more answer
if the service engine light is on have it scan tested for codes