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Discussion Starter · #1 · (Edited)
Yes it finally happened with 89K on the car. I had a 2000 Avalon and this same sensor failed between 85K and 90K. I've been dreading this one, but after reading a good thread about it here on T/N, and going out and looking at the problem, I have gotten confidence that I can do it. It may not be as tough as I thought, and I'm wondering if I even have to remove the air filter cover and the air resonator which is the standard procedure when getting at the sensor from the top. I removed the TPS cable and I moved the brake booster line above the hood, and it seems to be enough room. I won't know until I order the sensor and try to install it. Thanks to T/N for this great thread about it:


http://www.toyotanation.com/forum/1...-rear-bank-air-fuel-o2-senor-replacement.html

I'm almost certain this is the sensor for my car:
https://www.amazon.com/Denso-234-9021-Oxygen-Sensor/dp/B000C5YD42

I went down and took some pictures tonight...

A/F sensor near firewall



Connector



TPS cable removed



Brake booster hose and TPS cable removed for better access



Trying to save my back here--old man at work


It will take maybe a week to get it from Amazon. I think this is also what has caused the car to hesitate when I accelerate, and I know it is why my fuel mileage has dropped by 3MPG. As long as those threads are OK in the rear exhaust manifold, I think I can do it. We well see...





 

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Discussion Starter · #2 · (Edited)
I wasn't able to edit my original post, so I will continue in this thread with a new post. I was able to get the sensor loose with the 7/8" wrench today. I'm just waiting on the 234-9021 sensor to come from Amazon, and I don't think it will be much trouble to get it in.














 

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Discussion Starter · #3 · (Edited)
The new sensor is in, and the car runs just fine. It runs much better with the new sensor in. The cable on the new sensor is just a couple of inches longer in the rear, and it doesn't have the protective sleeve on it that the OEM sensor had. I used PB Blaster for a couple of days before I removed the old sensor, but I didn't use PB Blaster the day I took the sensor out because I didn't want the wrench to be all slippery. I was able to do this job without removing the air filter top housing or the air resonator or the 2 rubber tubes. I think the job would be easier to do if you removed these parts, but after taking them off many times before, I just didn't feel like doing it this time. I ordered the sensor from Amazon, but after Amazon Logictics failed to deliver the part I ordered it from Roc Auto. With the discount code and 2-day shipping the total was about $114. It says on the box that the sensor is made from foreign parts assembled in America.


There are no CELs on now, and I would like to do the front one when I get the money. I wouldn't say this was an easy job, but it wasn't as hard as I thought it was going to be. You really need a lot of torque to break the old sensor loose. I put a light coat of anti-seeze on the threads of the new sensor. Take your time, and don't get in any big hurry when you do this job, and you should be OK.





 

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Nice DIY there Endzone! I added this to the DIY sticky at the top of this forum.

If any of you know of any other DIYs, just let me know and I'll add them also.
 

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Discussion Starter · #7 ·
Great write-up! Would you still recommend that O2 sensor? Driving impressions and gas mileage still good?

Thanks...Jody
I would recommend replacement of both sensors on the front and rear exhaust manifolds (A/F ratio sensors) between 90K & 95K even if you don't get a check engine light. My car continues to run strong with better acceleration after replacing them. But, it did not improve my gas mileage. I still get the same MPG after the sensors went in as before they were replaced. Also, the word on TN is that you should replace with the Denso brand sensors. Roc Auto has them (with the TN discount) for about $105.
 

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^Endzone speaks truth.
 

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Pictures were helpful! Both my A/F sensors were bad when I got my 2000 Avalon. Replaced bank 2 right away. Real easy since it is out in the open. Open hood, look down there it is. Hardest part was diisconnecting it. What a struggle! It was hard as a rock, like somebody super glued it in.
 
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