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Discussion Starter #1
About a month ago, engine light went on and we got a P0420 code. After some research on this site, I decided to replace the after cat O2 sensor and stand it off a little bit from the exhaust pipe by installing it in a spark plug defouler that had been drilled out. That seemed to do the trick and all was well for about a month.

Now, we are getting a P2270 and P0054. The P2270 is O2 sensor stuck lean bank 1 sensor 2. I used my scantool and drove around yesterday looking at the voltage for the sensor. I seem to be getting continuous feedback and it's reading between 0 and 0.5 volts depending on the acceleration so it isn't a drop in signal. Maybe it was the cheap off brand O2 sensor I bought?

Any thoughts on what could be causing the lean reading? The obvious one to me is that the sensor isn't in the exhaust stream but I'm afraid moving out of the defouler will just bring me back to the P0420 code again. I don't intend on dropping $ for a new cat.

Thanks
 

w/ my magic bag
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The o2 needs to be in the exhaust stream to read correctly.....
 

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Discussion Starter #4
Why did you stand it off, the code was still there without it on the new sensor?
I skipped a step in troubleshooting and went right to the defouler. Good point - I should remount the sensor directly where it is supposed to go and see if I get the P0420 back.
 

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I had a coil pack connector plug failure on my 02 and let it go for a couple of weeks as I tracked down the failure. Random misgire code turned to the 420 after the pigtail fix. Had to replace the converter to get rid of the code.
 

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Discussion Starter #6
Ok - removed the defouler and installed the new O2 sensor directly where it's supposed to go. I cleared all codes and it didn't take me long to get P0054 but only that code this time. I'm going to read the resistance across the sensor itself to make sure I didn't get a faulty replacement sensor. Is there anything else that could be causing this?
 

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Ok - removed the defouler and installed the new O2 sensor directly where it's supposed to go. I cleared all codes and it didn't take me long to get P0054 but only that code this time. I'm going to read the resistance across the sensor itself to make sure I didn't get a faulty replacement sensor. Is there anything else that could be causing this?
Wiring is a possibility, is it getting power to it? Ohms check is a good idea I have gotten quite a few new parts that were bad over the year.
 
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