Denso 234-9056 Air Fuel Ratio Sensor

Easy to install,OEM quality and great performance as expected from Denso which makes the toyota parts.This price is way better than: Pep Boys,Auto Zone,Rock auto and Advance auto parts.At least in Puerto Rico they are asking $280 without taking into consideration shipping/taxes/any other fee.

This sensor has a "ring" or "collar" around it that requires a thin-wall sensor socket. I used the "CTA Tools 2064 Thin Wall Oxygen Sensor Socket" B005OH0ITM. It was still tough to remove without moving the inverter. I was able to get it from below after removing all the stuff in/around the wipers at the cowl. I used liquid wrench and ran the car to heat up the manifold. It still took two people, one working from above, another working from below, to get this sucker to move.Sensor is name brand. It might even be OEM. Avoid cheap weird brand sensors. You do not want to repeat this repair.For my 2005 Generation-2 Prius:This is not an oxygen sensor. It is a more expensive air/fuel sensor. I have seen multiple catalog listings that show the same sensor in both the upstream and downstream applications, which is wrong. If your upstream sensor is not twice as expensive as the downstream sensor you likely have the wrong part.My error code referred only to the downstream sensor. I replaced both the upstream sensor and downstream sensor based on my internet research. The upstream can start failing enough (silently) to cause the downstream sensor to trip. Also, they are rated for 100k miles and I was at 120k. You do not want to foul the expensive Prius catalytic converter, especially if you have a California car!

Purchased as the Air/Fuel ratio upstream O2 sensor for a 2nd Generation 2006 Prius.I think that using the right tool is better than grinding down the diameter of a generic tool. I also purchased a Schley Products 66750B Shielded Oxygen and Fuel Sensor Socket to remove the O2 sensor. The Schley tool looks almost identical to the Toyota 09224-00010-01 02 sensor socket which costs $120.Once I removed the windshield wiper arms, the plastic shroud, the windshield wiper gearbox, the relay box attached to the lower metal shroud, and the lower metal shroud, I could see the O2 sensor. I was not able to spray liquid wrench onto the threads until I removed the heat shield attached to the exhaust manifold. The heat shield was attached to the exhaust manifold by 4 bolts with 10mm hex heads. Using a 3/8 ratchet wrench on the Schley 66750B tool, the O2 sensor became loose a lot easier than I expected.

The heat shield will prevent most normal O2 sensor sockets from working. Be sure that you have a thin walled O2 sensor socket ready as this will be critical for installation.Also note: if you're trying to install in a Gen 2 prius it is a direct fit, however most thin walled O2 sockets are too long to use without removing the inverter. I have seen some which appear to be stubby and may work, but I spend hours on mine.

If your mechanical this is not hard to do yourself. I used the thin walled 7/8 CTA 22 mm Thin Wall O2 Sensor socket, and had to us a wrench on the socket because there was no room to get the ratchet in there. I removed the wipers, cowling, wiper motor, and worked my way down. Took about an hour maybe 1.5 but i do all my own maintenance and diagnostics.

Saved a little money by buying directly from NGK vs buying a Toyota branded NGK product. Exact OEM replacement.

I purchased this for my Prius as my check engine light was still on after replacing the catalytic converter (300,000 miles on the car). The dreaded P0420 (catalytic convertor efficiency) came on so I did what I did the previous year for inspection, put on a new convertor. The light went out for 20 minutes and came back on. I guessed that the A/F sensor was dead too so I bought this one and haven't had a problem for the past 10,000 miles.Using a cheap sensor the first time made sense as my car was burning oil at a horrendous rate (a quart every 500 miles). The cheap sensor and a new cat got me through the inspection which gave me time to run the car long enough (the whole next year) to get the oil control issues sorted out. Now with the OEM sensor and the oil usage well withing specification (spec is 1 quart per 1000 miles maximum, I am 0.4 quarts per 1000 miles), the sensor will last. I got a little boost to my mileage as well.

purchased this sensor 10 months ago. Had to buy a specific tool to install it with the shield. 10 months later, now I'm getting code for sensor stuck rich.

Denso is the OEM for this part. After 190K kilometers there was no way I could loosen it. Had it done by someone with more and better tools and we made sure to put anti-sieze on the threads (keep it off the sensor). 2009 Corolla runs like new.This sensor also fits my 2010 Corolla. Amazon fitment says is doesn't but that is not correct. I check a part's fitment on PartsGeek and RockAuto. Amazon's fitment is too often unreliable, but Amazon does sell a lot of Corolla parts at a price that is comparable to Rockauto's and shipping is generally free, especially if Amazon is the vendor.

Amazon states that this part number is incorrect for my vehicle. OEM PART does fit a 2009 Toyota Matrix 1.8l.

Had code P0031 for heater circuit low voltage B1S1 on a 2010 corolla, CEL hasn’t come back on since installing new sensor. Delivery was unusually slow but well worth the wait. Do yourself a favour and buy this OEM sensor, you’ll be thankful.

The sealed package was already open,thats why I give 4 stars. My toyota matrix 2009 keep throwing p0295 and p0138 code and the car had poor gas mileage. With the new o2 sensor, no more check engine everything back to normal. And at the dealer the same brand cost 340$.

I'm very please with this purchase.