Nestorsh

Can someone tell me the location for the O2 sensor on bank 1 sensor 1 on a Nissan Maxima 09?

User1

Right on top of the manifold. Can't miss it.

Nestorsh

Great, one more thing, autoparts webpage shows them as upstream front and upstream rear, but I dont know which is the right one for bank 1 sensor 1. Can you tell me?

User1

Firewall.

Nestorsh

That make it rear upstream... i guees?!

User1

Depending on the month of production of your vehicle, you need one of the two part numbers below:

From 05/2008-08/2009
https://www.nissanpartsdeal.com/part...-module,,22693

From 08/2009-08/2011
https://www.nissanpartsdeal.com/part...-module,,22693

Shop around for a better deal, they're out there.

Nestorsh

Great, i got the part, now I’m trying to take it out, is in the back of the engine by the firewall like you said. But no luck taking it off, is a small place and can’t work, and it’s really tight. Any tips or ideas?

User1

I dunno man. I'd have to see it to figure it out. O2 sensors are usually pretty tight. Don't round it off or you're screwed.