Hi, new here to the forum. i have a 05 ram 1500 with 5.7 hemi and i need to replace the 02 upstream oxygen sensor, where is that actually located in the exhaust? went bad afew months ago and got to apoint that the truck hesitates and stalled out on me the other day.. rpm up and down.. is it easy to replace? also is this only a dealership part or can i get one autozone or somewhere else? thanks guys in advance..

 

upstream is PRE cat


easy job. unplug the o2 and remove it

thread the new one in and plug it up

if its 4wd make sure it doesnt rub on the front driveshaft (driverside)

 

You can get an O2 sensor at any auto parts store. I think in 04 they made them with 4 sensors, since there's 2 cats (2 before, 2 after). Someone will chime in to either support what I've said or refute it. My parts book says I should have 4 with 2 cats, but in reality (as in looking under the truck) I have only 2 with 1 cat. I recommend getting up in there and visually verifying it yourself before you buy anything. Hell, if you pull one down you can even get a part number off it.

 

Yea it has 4 sensors.two before and two after. i had it coded and they said it was a upstream sensor but i have to a call them tomorrow and ask if its the left or right side. it didn't state on the invoice which side. this was back in november when i had it checked so i hope it's still in their computer if not i'll have to replace both sides, i'm not paying again to throw it on a computer.

 

It won't say which side, it will just say upstream sensor.

 

It tells you what side it is when it is the downstream sensor, so the code should tell you the same for the upstream. It will say something like sensor "2/2" where the first number tells the side and the second is up or downstream. Or it might be the other way around but it will tell you what side the code is for.

 

Yep, it will say bank 1 or 2 and upstream (between engine and cat) or downstream (after cat). Bank 1 is the side with cylinder #1. Bank 2 is the opposite. On GM and Dodge, Bank 1 is the driver side. On a Ford it is the passenger side.

 

That's what has me stumped, you think on the invoice it would say which side. maybe i'll just replace both and have it over with.. going to autozone tomorrow to pick both of them up. have off work so might as well do it.

 

autozone should be able to tell you what side is bad they do free scans rght

 

Replacing both can get expensive, especially if you go with the factory replacement part.