Hello,
2014 Scion XB 80k mileage, automatic tranny. My relative’s car throwing a code Catalyst system efficiency below threshold (bank 1) replaced bank one sensor, replaced faulty PCV valve that had oil in it, removed front 02 sensor and cleaned inside the catalytic comverter with mass airflow sensor first time, didn’t work, a few days later cleaned with throttle body and air intake cleaner with catalytic on the car, didn’t work either, reset it and the check engine light and traction control light keeps coming back at the same time after about 40mins of driving, has strong pollution smell, and the hood vibrates a little, otjer than that no other issues drives and accelerates well. Every time she buys a used car she gets burned and I end up helping her out for free. Read online can be muffler, ect sensor, and catalytic converter. Also checked online can use cataclean and lacquer thinner, but seen some test results that these two products deteriorate O-Rings, so will avoid these two products. She is very low on a budget, is it possible to maybe remove the upstream sensor and drive without it? Or maybe loosen up the upstream sensor so the pressure doesn’t build up and doesn’t blow head gasket? The 02 sensor is located under the hood in front of motor in this car. Any opinions from all of you, or links to videos, suggestions will greatly appreciate it. Thank you
Does the engine burn oil? Burning oil could well have poisoned the catalyst if so. (Even with only 80K miles if not maintained the engine could be shot - or the mileage could be faked.)
You don't want to remove the upstream O2 sensor since that is used as feedback for the fuel injection system. It can be removed temporarily to hook up a back pressure gauge to see if the converter is clogged and that should be done if excess back pressure is suspected. (If that is the case it won't blow the head gasket but the car would have little power and would not be able to reach highway speeds.)
However if the car is running OK aside from the catalyst code and doesn't need to pass emissions inspection it can be driven as-is.
You could try cleaning the converter this way which seems to work for some people, but if the engine is burning oil it's ultimately going to ruin the catalyst:
https://www.youtube.com/watch?v=1uukKrgBXeo
Hello,
Thank you for for your prompt response, in regards to the question that previously asked, not sure if car is burning oil because my relative she recently purchased it and has driven it short distance only, but I’m sure it was losing oil due to oil in PCV valve that I replaced, and replaced 02 upstream sensor but that didn’t fix the P0421 code, traction control & check engine light came on at same time, I would like to ask is it okay to remove the upstream 02 sensor and use a funnel and pour in there 1-2 bottles of seafoam, or laundry detergent mix with some water, or carpet cleaner with water, than let it sit for a day? just to give it a shot if it might work.
Noticed the threads on old upstream 02 sensor and on catalytic converter was rusted where 02 sensor goes in, but the heating element that goes inside catalytic converter was not, there is some kind of white corrosion all over the engine and transmission, I used engine degreaser and removed some of it from the top, see pictures, also took pictures of what spark plugs look like, not sure if a used car dealership that previous owner purchased from maybe used pressure washer or some kind of chemical to make it shine in the past
https://postimg.cc/bDZxQw9S/f80e4b25
https://postimg.cc/1nvdzX5g/5c9c536b
thank you
I don't know about pouring in cleaner through the O2 sensor hole, never heard of anyone doing that and I don't know what it will do to the rest of the exhaust system. From what I can see you'll be blazing a new trail if you try it. The spark plug pics look pretty much normal.
not sure how to reply to the same person who answered the question
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Hello,
in regards to the question that previously asked, new to this channel not sure how to reply to the same person who answered the question, I appreciate the help, so reposting with previous and new concern questions. 2014 Scion Xb, mileage 80k, was asked if car was burning oil, not sure because my relative she recently purchased it and has driven it short distance only, but I’m sure it was losing oil due to oil in PCV valve that I replaced, and replaced 02 upstream sensor but that didn’t fix the P0421 code, traction control & check engine light came on at same time, I would like to ask is it okay to remove the upstream 02 sensor and use a funnel and pour in there 1-2 bottles of seafoam, or laundry detergent mix with some water, or carpet cleaner with water, than let it sit for a day? just to give it a shot if it might work.
Noticed the threads on old upstream 02 sensor and on catalytic converter was rusted where 02 sensor goes in, but the heating element that goes inside catalytic converter was not, there is some kind of white corrosion all over the engine and transmission, I would of attached pictures but have no idea how, not sure if a used car dealership that previous owner purchased from maybe used pressure washer or some kind of chemical to make it shine in the past
thank you
To attach pictures, see here - https://carkiller.com/scottykilmer/postid/183035/