Kia O2 sensor

[CoreyVanDine]

Ok guys I'm new here but I have an interesting issue on a Kia Sedona. Came in with a p0138 (bank 1 sensor 2 high voltage) and a p0455 (evap large leak.) monitoring the O2 sensors came up with something a bit odd. The specified range shows to be ~ .06-.07 on b1s2 and b2s2.



So keep in mind the code is for high voltage on b1s2. This is engine warm at idle.



I see that b1s2 voltage is indeed slightly high at times but for the most part it looks to be in range. Now look at b2s2.



Am I wrong in thinking the b2s2 is way out of range? At times almost just as high as b1s2 but mostly low? Drivability is fine except for maybe a slight rough idle. 150k on the odometer. I don't feel I have enough of a cause to bolt a b1s2 on it yet. Shot of both banks together.



Bank 1 Sensor 2 looks to have a slow response that bank 2 sensor 2 but why a high voltage code? Any input would be great!

[Modis500]

Seeing alot of activity on that B2S2 as if a CatConverter is acting lazy...just my 2cents

[Nickb]

Ditti on the convertor. Back o2's shouldn't have activity like that.

[Joe Rappa]

If you don't find a leak with the P0455, make sure you check the purge valve. Sometimes they don't turn on and set a gross leak code, even though there's no leak in the system. Not uncommon for the purge valve to fail on them.

Joe

[CoreyVanDine]

Keep in mind this is at idle. Fairly normal for increased activity on post cat O2's at idle? Big question is why the high voltage code? No catalyst code. P0455 was the canister closed valve and hose that goes to the valve. Valve stuck open and hose split. These screen shots were taken after the evap repair and after 3 drive cycles with no return of the cel. O2 code has not returned but the values still look wrong. Not ready to close the book on it just yet.Thanks for the replies!

[Crusty]

The indications are there for a bad converter BUT, the post-cat sensor isn't only dependant on the Cat-efficiency.

Check both PRE-cat sensors and make sure they're both in full fuel control and have good amplitude and frequency. There could be something ahead of the O2 sensors such as ignition, injectors, etc.
The two Pre-cat sensors don't look EXACTLY the same, yes they initially appear similar but I would want to confirm what's going into both banks of the exhaust stream first.

Check the "enabling conditions" for the hi voltage code and also the "code set criteria".
Sometimes it may see a high voltage above 1.000 due to a shorted O2 heater and thus suspend using that sensor to flag a bad cat.

[Modis500]

Corey,

Totally unaware that this info was @ Idle...didn't see any RPM reading on your screenshot, and no info from you as to engine speed, so I believe some of us assumed (and you know what assuming does!) that this was at a steady cruise. Some more info would be helpful next time, but nonetheless, yes sometimes the downstream do have some higher activity @ idle. Upstreams look good, maybe get us a screen shot at a steady cruise speed for add'l data.

Tom

[CoreyVanDine]

I probably shouldn't have put that this was at idle in between two screenshots! Everyone loves pictures so much its easy to miss those boring words!! Its right after the screenshot of the specs. "So keep in mind the code is for high voltage on b1s2. This is engine warm at idle."

Here's one at cruise speed. B2S2 certainly indicates a bad cat. Bank one doesn't look a whole lot better.





This is after a new B1S2. Much better but not perfect.






At this point I'm convinced that a cat would make this car right but that can be a hard sale in a state with no emissions testing. I drove this car about thirty miles today (shutting it off several times) after the new sensor with no codes. My confusions stemmed from the high voltage code. What Crusty said makes sense about the comp seeing the high voltage and no longer searching for cat efficiency. The other strange thing was how uniform the voltage was on B1S2 at idle. Almost as if the signal was computer controlled and not depending on the cat at all. I would still like more input if anyone has anything to add. Unfortunately the customer decline any further repair at this time so a definitive result can't be TOTALLY proven. Again thanks for the replies and the hospitality.

[Modis500]

Corey,

Thanks for the add'l info. And Yes, I did see that information in between the screenshots, just un-aware all the shots were @ idle. B1S2 definitely looks better after replacement, but that B2 Cat is probably toast. It will be a hard sale for a Non-Emissions state, as customers believe they should only do the minimum...sad state of affairs, especially here in Charlotte, as we have a Non-Emissions state directly below us, with many of the dirty SouthCarolina residents driving north into our state and our main EPA testing station is a mere 5 miles from the border, and on a main road, so we get a bad rap for allowing out-of-state workers with Emissions problems on probably 50% of these vehicles(if you seen what drives through into our region, you'd cringe sometimes!)and the EPA says we have one of the worst records since they started testing, and currently we don't pass 1995 EPA Regs!!!! Thanks SC for your dirty cars! Okay guys, sorry for venting, kind of a sour subject for many of us that have to keep our cars current and clean on Emissions. Falls on deaf ears, however maybe our local governments should state "...any vehicle owner that works full-time in a neighboring state shall follow all emissions and safety regulations in that county/state" Hahahaha, like that'll ever happen!

[Bob's Garage]

Hi Corey,

I posted an answer to your post you started over in the general discussion forum.

http://productforum.autorepairdata.com/forum/showthread.php?p=38777#post38777

[Bob's Garage]

Corey,

Thanks for the add'l info. And Yes, I did see that information in between the screenshots, just un-aware all the shots were @ idle. B1S2 definitely looks better after replacement, but that B2 Cat is probably toast. It will be a hard sale for a Non-Emissions state, as customers believe they should only do the minimum...sad state of affairs, especially here in Charlotte, as we have a Non-Emissions state directly below us, with many of the dirty SouthCarolina residents driving north into our state and our main EPA testing station is a mere 5 miles from the border, and on a main road, so we get a bad rap for allowing out-of-state workers with Emissions problems on probably 50% of these vehicles(if you seen what drives through into our region, you'd cringe sometimes!)and the EPA says we have one of the worst records since they started testing, and currently we don't pass 1995 EPA Regs!!!! Thanks SC for your dirty cars! Okay guys, sorry for venting, kind of a sour subject for many of us that have to keep our cars current and clean on Emissions. Falls on deaf ears, however maybe our local governments should state "...any vehicle owner that works full-time in a neighboring state shall follow all emissions and safety regulations in that county/state" Hahahaha, like that'll ever happen!

Remember this: "Emissions programs are not about clean air. Emissions Programs are about politics and money"

I could go on, but no ranting before bed or I'll have nightmares.

[Crusty]

Remember this: "Emissions programs are not about clean air. Emissions Programs are about politics and money"

I could go on, but no ranting before bed or I'll have nightmares.

ROFLMAO.....TOO TRUE-!! Thanks for the chuckle Bob.

[Modis500]

Bob,

True enough...should have stopped and thought for a minute. EVERYTHING is politics and $$. Thanks for the refresher course

[sandt38]

Check your purge valve. If it is sticking open it could set high bias O2 codes.