Bad O2 sensor?

[supton]

Pulled the codes for a friends '11 Sonata. I looked up the codes and it seems like it's got a bad sensor, but maybe it's something else? I'm thinking of clearing codes and seeing what comes back. I'm not sure what to make of the too rich/high and low/lean codes though.

P0136: Post O2 low V
P0140: no post O2 activity
P2096: post catalyst trim too lean
P2271: post O2 stuck rich
P0138: post O2 too high

Pending P0136 and P0140

 

[skyactiv]

You have access to an oscilloscope?

 

[andyd]

O2 has 100k miles? Change it. A new one will bounce between .2v and .9v . Sounds like yours are bouncing too slowly. Just a wild guess.

 

[supton]

I do have an o-scope. But that jogs the gray cells, I recall Torq has a graphing function. I used that to determine I had a bad O2 sensor in my car (which oddly never tripped a code). Maybe next week I'll look into that--not sure how much help I want to offer, 7 years of road salt should mean it'll come out easy, right?

Yeah, over 100k on the clock, like 178k.

 

[StevieC]

I had similar codes in My Santa Fe when it went bad on me.

 

[slacktide_bitog]

You need a new downstream oxygen sensor. Denso and NTK are the best ones to get

 

[clinebarger]

Most likely a bad O2 sensor......Getting stuck low then stuck high.
If this was a hard short in the wiring.....It would be stuck Low or Stuck High at all times!!

I don't know this particular vehicle very well, However.......If the signal circuit was shorted to battery power......The O2 voltage reading in the data stream will read over 1.00vdc which is a voltage the 02 sensor itself cannot produce.

Do you have access to scan data?

 

[The_Jeff]

Unplug it, hit with a little PB blaster, put a 7/8 box wrench on, start it up for just a minute, then hammer the other end of your wrench. She'll come.

 

[JTK]

Given the conflicting codes for the same sensor, I'd check it's connection and wiring first, then try a new sensor.

 

[spasm3]

178K miles? I'd just change the upstream ones. I change mine at 80-100k miles as a maintenance item, cheap enough to do myself and prevents cooking a cat, if it goes out on a long trip.

 

[WyrTwister]

Were it me , I would go ahead and buy a sensoe , then jack it up and check wiring . If wiring was OK , replace the old one .

Do not know how many O2 sensors the car has , but visually inspect all of them while you are under there .

 

[supton]

Should just be two for an I4. Too busy this weekend to work on, not sure when I'll see the car again.