I have a 4.7l 2000 Druango that is throwing code p0138 which is telling me its an o2 sensor (behind the cat I believe)
With this being bad would it cause a carbon smell once in a while and black soot to build at the end of the pipe?
Also I put high octane fuel in last time before the code went on by mistake so not sure that would have to do with anything?

Thanks

 

Also, I think I replaced this same sensor about 2 year ago when it was around 100k (now has 125k)

 

the carbon smell is not caused by a bad O2 sensor, tho it could make the computer think you have a bad O2 sensor, the high octane fuel wont hurt anything except your wallet so dont worry about that, it sounds like you either have a bad O2 sensor or a bad catelytic converter, it is also possible that it is a different sensor that went bad the 4.7l engines have 4 O2 sensors (2 per side) so chances are it is the post cat sensor on the other side of the engine which is bad

 

P0138 1/2 O2S Shorted To Voltage


I think that is the pre-CAT sensor on the drivers side. Replace it with OEM 02 sensor.

 

if it just shorted (i know JUST lol) and you have had alot of rain lately, or driven through alot of puddles clear the code and see if it come back, if it doesnt come back dont worry about it, i got that code last june when the NE part of the country had almost a month straight of solid rain and i got lost i downtown patterson (NJ) and it was flooded, so i got stuck driving through it.

 

+1 Sharps!


I forgot about that.

 

Thanks for the reply's.
We did just have a lot of rain for a few days win Snow just leaving. The sensor i replaced a few years ago was a generic Bosch and it was just tied into the old wiring so maybe water got into the connector and shorted. (the one after the cat)
I will try and clear code, I need to get the car e-checked before the 10th when I need new plates by!

Thanks again.

 

I pulled the o2 after the cat and it was black from carbon I guess. I put the new one in, started the Durango up and the light never came back on.
Took it to eCheck this morning (get it done in case the light comes back) and it passed but did fail on the gas cap which they give them free if you fail that part.

Now I just need to find out why that o2 got so black,, would a bad cat cause this?

Thanks.

 

im going to say no a bad cat would not cause it, im not really sure what would cause it, but IMO a little bit of build up is normal but im not sure how much you have pics would help

 

Here is the pic. Maybe it is normal then. Just looked very black along with my exhaust tip being very black also.