P0420 solutions?

[Nelsonmd]

My answers in bold.

Yeah, I can tell you for sure that my 2000 non-cali auto has a short vehicle side harness. I have thought about getting a new 234-4162 just to see if it fits correctly, but I got by inspection, and it only comes on maybe once a week, which I just clear out with my SG2, so I don't care too much and don't want to spend an unnecessary $70. If the actual sensor is the same, then I would just get the longer tail one anyway and zip-tie it up there.

Man, I could have sworn that the front O2 doesn't affect fuel trim on the non-cali's. I thought it was just an O2 sensor, not an a/f sensor on non-cali's, and just measured for exhaust analysis, not fuel trim.

 

[silverturbo]

2000 4Runner 4WD Limited w/Cali-Emissions

I changed my Bank 1 / Sensor 1 Part# 234-9002 and it got rid of the P0420 code. Prior to doing that, I metered the sensor and it didn't show any continuity. It verified that it was the problem so I replaced it along with some new nuts.

 

[fblainen11]

On my 4Runner I was able to remove the O2 sensor with a normal wrench and/or socket.

My 05 Land Cruiser needed an O2 sensor socket to remove. Can borrow them from parts store.

The Denso brand will be just fine and you'll clear it right up.
Inspect the nuts before you start the job. If there's a hint of rust, get new nuts.

Either way, make sure you use PB Blaster soak it several times starting a day or so before. The hardest part of this job is disconnected and reconnecting the wiring harness.

 

[silverturbo]

So my CEL came back on after a couple of days being off... i just replaced the o2 sensor and drove for 60 miles... so far so good. Fingers cross.

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[silverturbo]

Well, fingers were crosses CSEL back on after 750 miles. Erased code and came back on after 30 miles.

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[catrains]

Well, fingers were crosses CSEL back on after 750 miles. Erased code and came back on after 30 miles.

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the downstream O2 sensor bank 1 sensor 2 is what will report signals that indicate the converter is not working effectively ..

possible it is a bad sensor or wiring or converter. converter 17 yrs old very possible its bad. the O2 sensors do require replacing around 100-130K miles .. sometimes they do fail at a lower mile like I had @80K miles. 2005 T4R ... if you leave the vehicle running for a good amount of time like in winter so it will warm up that will do it ..

 

[19963.4lsr5]

Try a bottle of Cataclean from the autoparts store. And take a trip.


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[silverturbo]

Just notice your reply... sorry. But i went ahead and replaced both cats sense I have already replaces both sensors prior to. Lets see how it goes and I'll try not to take too long to reply.

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