O2 issues
 

Alright, so I have a 2010 Z 65k miles. Back in january the fuel pump died. At the time it was already throwing codes p2a00 and p2a03 for both upstream sensors. I figured the pump was the issue and replaced it but the light never went away.
Fast forward to february when my fender liner falls off and my car sucks up water. I live in the north so salt is everywhere. Salt coats the filters and maf sensors. I just replaced the filters and maf sensors on Thursday, as well as a clogged up pcv valve and spark plugs while I was at it.
now, the car is throwing codes or both downstream o2 sensors. All I can think of is that the salt killed them but why is it just now popping up? Im not sure if I should just replace all four sensors or what?

You have high flow cats right? Those are sensor 2 codes, meaning post cat. I wouldn't worry about them, they have zero effect on how your car runs.

I have been running fast intentions hfc for quite a while with no secondary o2 codes until now. And it is not the cat inefficiency code.

How old is the "historic" fault?

Since December but it has been ongoing

The sensor 1 code is the more serious -- that sensor might need to be replaced.

The bank 2 codes are most likely due to the HFC's, and shouldn't adversely affect anything. Replacing the sensors may or may not make a difference in getting the CEL.

Im hesitant in saying the downstream codes are from the hfc. The code is saying low voltage and slow response. Not catalyst inefficiency.

I have seen codes thrown for the same thing when using nonfoulers / O2 extensions, it's not always inefficiency.

I appreciate the input.
as far as the upstreams go, both of them have been throwing codes in the past although only one is being shown as historic. Its just confusing to me that all 4 are throwing codes

First, the p2a00 and p2a03 are codes a number of use have had on here with little to no reason. I believe some have found intake piping leaks and that remedied their problem. In my case I checked the AFR while the car was running and didn't see any problems that would justify the code. In the end I just turned the p2a00 and p2a03 codes off through uprev.

Now onto your other codes. I had the exact same codes except on the primary o2 sensors last summer after an autox oops broke both my primary o2 sensors. For o2 sensors to work they need power and atleast on our cars there's a fuse in the power circuit. In my case the fuse was blown as a result of the broken o2 sensors. I'd check the service manual (should be able to find a link to it on here) and locate the fuse and make sure it's still good. More likely than not it's in the fuse box buried next to the battery meaning you'll have to pull the battery to get to it.

Also if you do end up replacing the primary o2 sensors make sure you get the right ones. I believe it was mid 2010 that they changed the connector resulting in a different part number. I know when I got mine almost nobody showed that there were two different sensors depending on build date.

Just checked the fuse box and the fuse is not blown.
thanks for the info about the o2 sensor. I thought it wasnt until 2011 that it changed. Ill be sure to order the correct sensor if I go that route

http://i.imgur.com/p3StBEG.jpg
I logged the O2 readings today. They are constant at .28 volts. Unless anyone can chime in and say otherwise, to me that means they have gone bad?

So I replaced the downstream oxygen sensors. One of them were completely plugged with steel wool from last summer when I was running test pipes. I assume that was causing the codes for the downstream sensor

Hmm. So before the steel wool broke off and clogged the O2 did it keep the CEL off?

I wonder if some sort of filter screen might work better.

Glad you resolved the problems :tup: