more questions about CAT+O2 sensor

Hi, all I got a lot of kind responses after I posted my original questions regarding to CAT+O2 sensor. I feel such relief after reading your responses. So far, the engine check light is still off and I am anxious to see what will happen next. I have some more questions after reading your responses:

  1. Is it possible that I pumped some "bad" gas that caused the whole problem? I keep pumping the cheapest gas I can find and never stick to the brand
  2. How could dealer's mechanic tell the internal worn of CAT? Can such internal worn be detected virtually without taking down the CAT?
  3. I am thinking about purchasing an OBD II scanner. If check engine light is not on, Can I still use it to do some kind of early detection of my car, e.g., whether the car will pass emission test, etc?

Thanks.

Reply to
wenmang
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Possible, but unlikely.

They can measure the exhaust gas downstream from the converter. If it isn't meeting specs, the converter would be considered bad. Most likely, they were just looking for the quick and profitable fix (replace everything related to the code, fix the problem, and make lots of money).

You should be confident if the check engine light is not on, you will pas the emissions test. That is why the O2 sensor after the converter is there. It is nice to have a code reader, so you can diagnosis your own problems.

Ed

Reply to
C. E. White

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