O2 Sensor Problems
 

Hi everybody,

Here is the 411:

So I ran a header for about a year then took it off because I didn't care for it after a while, I had no O2 problems because I ran one of the 90* angle things on the secondary O2. Then I replaced it with the original manifold and about after a month I had problems with codes.

I replaced both sensors because the car has 117,xxx miles on it and I figured it needed it. I replaced them now I am thorwing the following codes:
P0031 HO2S Heater Control Circuit Low (Bank 1 Sensor 1)
P0037 HO2S Heater Control Circuit Low (Bank 1 Sensor 2)

After replacing them with cheap ones, I thought it might be that the cheap one was a bad sensor at first so I went and ordered a new OEM one from Toyota only to have the same problem.

I read on a Nissan forum somthing about their manfold being messed up and that corrected the issue when they replaced it. Is there anybody in the area (Boston area) that has a stock manifold for a 2005-2006 tc so I can see if this is the issue? If it is then maybe I will buy it off ya.

Any ideas? I'm poor and I need to get my car inspected and emessions tested in 2 weeks. I have spent about $135 so far and still have the same problems. :pray:

here are some details from a past post:

https://www.scionlife.com/forums/vie...ighlight=p0037

my car just threw the P0037 code also so im looking into it. Is this sensor the one on the header itself? First thing im going to do is disconnect the battery and have it reset the ecu and see if it comes back on. its o2 so i know that its nothing that will affect the car so a few days with it on is no issue to me.

whats the cost of the P0037 HO2S Heater Control Circuit Low (Bank 1 Sensor 2)
and where is the best spot to buy it?

this is something i thought i could just get at a junk yard but i was looking for an index. i guess i would have to call the yard that has a tc and ask them. i have no clue.

yea - shut my light off and it comes back on w/ the same code. where is the best spot to get this sensor from? I will need to replace it.

so, both your A/F sensor and your 02 sensor are throwing low input codes huh? that's weird. ill have a think and check my fuel systems book and get back to you.

I was getting the p0037 which is the second sensor - i let it go and my car was barely able to pick up speed going up hills - scared the crap out of me - im glad i fixed it because i didnt even want to go to work tomorrow (it was that bad).

thats weird. the second sensor i listed is the post-cat 02 sensor that's just there to monitor cat function. that shouldn't effect driveablity. a bad A/F sensor would though.

^ i did see that the wire was eaten into (meaning the coating was frayed) - all i know is that as soon as i replaced it the car now runs perfect. its night and day difference

^ which sensor was it in the end? the one in your exhaust manifold or the one after the cat?

so now the car runs a lot better but after driving 20min the car bucks every so often. The car drives A LOT better but still something is wrong ..... what the heck

the one after the manifold and before the cat. Pretty much had to reach my hands up and wedge them where the crank is

ah. i figured as much. yeah, a bad A/F sensor will cause severe problems because your PCM loses it's main feedback concerning whether the engine is running rich or lean. like i said, the post-cat o2 sensor is just to monitor cat effciency.

Is your cat(s) clogged? I've seen issues like this before where the O2 went bad and then were replaced but the cats were clogged to hell and it still ran funny. Just something to check out. Also try reseting your ECU by disconnecting your battery for a while so the computer can relearn the fuel trims.

^ thats what I was thinking. I brought it to a shop and they tested and said the cat was ok. This sounds like a stupid question but I heard a rattle and I think some weld let go inside by my sensor - i dont hear it all the time though. There is no way for that to pass through the cat right? The cat should be honey comb shaped right?

My secondary one was honeycomb so I would "assume" that the main one connected to the downpipe assembly is the same. I'm not sure about the rattling noise but just to be sure about everything (given all the problems you've been having) I'd take off the downpipe assembly and disconnect it from the S-Pipe to do a thorough bench inspection of the cat, any welds, the donut gasket, and support brackets. There are a few brackets underneath that may not have been tightened properly if the shop did a half a$$ job.

You can also check your spring bolts from your S-Pipe.

^ i started to hear it after i replaced my sensor. it was full of crap so i had to put a wrench on it and tap it with a hammer a few times (so i wouldnt doubt it free'd up something in the pipe). I just wish their scan tool picked up something so I had more to go off of. I made 3 10minute trips and the car was perfect (after the sensor replacement) and only today when i was going to work (30minutes) the car bucked once right before I pulled into the parking lot

the wire coating was frayed on one part and i think that was causing the sensor to bug out. After replacing it the car atleast ran and didnt loose all its power going up hills (scary stuff)

It is possible that it could be a piece of carbon build up but I would try to find out why there was so much carbon build up in the first place. The car would have to be running too rich for quite some time for this to happen. Any CEL's?