About TRQ: TRQ is a trusted brand dedicated to making every repair a success story by combining premium parts with easy installation. Each TRQ part is engineered by a team of automotive experts to meet or exceed OEM standards, delivering enhanced performance and maximum longevity. With rigorous in-house testing, the brand ensures superior fit and function across every product line. TRQ also provides customers with best-in-class, step-by-step installation videos—so you can complete repairs with confidence, whether you're a first-time DIYer or an industry professional.
Product Features
Application Specific Design: No modifications and pre-calibrated
Isotatic-pressed and plasma-sprayed for extended service life
Double-Layered 310S Stainless Steel: Additional protection from moisture and debris
Restored Engine Performance: Improved fuel economy and lower emissions
Description
TRQ oxygen sensors are manufactured to precise specifications using premium raw materials to optimize your vehicle’s emission system. Each sensor is isostatically-pressed for improved strength and durability, and plasma-sprayed to improve sensitivity and prolong the service life of the sensors. Oxygen sensors wear out over time and should be replaced every 60,000 miles to prevent poor engine performance. TRQ recommends replacing the oxygen sensors in sets to optimize fuel economy and reduce overall emissions. All products are fit and road-tested in our Massachusetts R&D facility to ensure we deliver on our promise of Trusted Reliable Quality.
What is Upstream vs. Downstream?
Upstream location is between the catalytic converter and the engine
Downstream location is between the catalytic converter and the tailpipe
Install Tip: You may be required to reset the vehicle computer after installation of this part.
Returns: Parts with electrical components cannot be returned once installed.
Attention California Customers:
WARNING: This product can expose you to chemicals including Lead and Lead Compounds, which are known to the State of California to cause cancer, and birth defects or other reproductive harm. For more information, go to www.P65Warnings.ca.gov.
Lifetime Warranty
This item is backed by our limited lifetime warranty. In the event that this item should fail due to manufacturing defects during intended use, we will replace the part free of charge. This warranty covers the cost of the part only.
Returns: Parts with electrical components cannot be returned once installed.
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Expedited is available on checkout to the United States, excluding Alaska, Hawaii and US Territories as well as P.O. Boxes and APO/FPO/DPO addresses. Final shipping costs are available at checkout.
O2 Sensors is it Upstream or Downstream
Created on:
Tools used
No Tools Needed
1. Identifying your Oxygen Sensors
Upstream oxygen sensors are located in between the engine and the catalytic converter
Downstream oxygen sensors are located in the catalytic converter or farther away from the engine than the catalytic converter
Locate your vehicle's firing order diagram
The bank that contains cylinder one is bank one
The bank that does not contain cylinder one is bank two, even if it does not contain cylinder two
Hi, I'm Mike from 1A Auto. We've been selling auto parts for over 30 years. We're dedicated to delivering quality auto parts, expert customer service, fast and free shipping, all backed by our 100% satisfaction guarantee. Visit us at 1AAuto.com, your trusted source for quality auto parts.
In this video I have a couple of oxygen sensors with me. While there are some aesthetic differences here, the wire lengths are a little different, the actual body and tip of the sensor are a little different, the threads and gasket are the same, and on the other end the connections are actually the same. I can plug these into either position on our vehicle. But if I had to ask you which one's upstream and which one's downstream, you probably can't tell just from looking at them. That's true of most oxygen sensors. The way you determine whether or not an O2 sensor is upstream or downstream is all done visually.
Your oxygen sensor position can be determined relative to your catalytic convertor. As the name suggests, upstream sensors will be located upstream or ahead of, in front of, above, closer to the engine than your catalytic convertors. This means that they see the exhaust gasses first. They then go through the catalytic convertor and to the downstream oxygen sensor, which will either be located in the catalytic convertor like our vehicle here, or after the catalytic convertor to monitor the gasses coming out of the cat and make sure that it's being efficient relative to the readings of the upstream O2 sensor.
The other determination you need to make is bank one versus bank two. Determining which bank is which can be done by looking at a picture of your vehicle's firing order. Whichever bank contains cylinder one is going to be bank one, and the other one, regardless of whether or not cylinder two is in it, is going to be bank two by default. These banks are true of V engines like V8s, V6s, and flat engines like Porsches and Subarus that have individual banks.
On inline four-cylinder engines, as long as they have one exhaust manifold like a Jeep four-liter or a four-cylinder Honda engine, you'll only have one bank with an upstream and downstream O2 sensor. There will be no bank two on the engine.
On our vehicle here, this is the passenger side, which we've already determined from the firing order is bank one. We have our upstream sensor here closest to the engine ahead of the cat. Then we have our downstream or sensor two here inside of the catalytic convertor. This could also be located somewhere after the cat. Here I have my two sensors for the vehicle. While they are aesthetically different, we can now tell this is my upstream sensor because it looks just like the upstream sensor I have up there. This is my downstream sensor. Now that we know which one's which, we can order the right part, correct the problem, and fix you up right.
Thanks for watching. Visit us at 1AAuto.com for quality auto parts, fast and free shipping, and the best customer service in the industry.
Product Reviews
4.7/ 5
★★★★★★★★★★
21 reviews
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86%
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★★★★★April 25, 2026
Fit perfect. Engin light turned off and it was packaged in a clear wrapper and also says match with old scensor before opening new new packaged scensor. Thank you A1 auto
★★★★★August 7, 2025
Like butter
★★★★★January 19, 2025
1A auto parts, your reliable parts store.
Their customer service is excellent. If you don't know and need help finding a part for your car. They will help you find it if you simply give them a call. Amazing customer service. I have bought headlights before this purchase it fits perfectly. They also have video tutorials if you are handy. My friend recommended 1A to me, and I am recommending to you.
★★★★★May 4, 2024
Perfect fit thanks
★★★★★February 28, 2024
Reliable
Helps to have a reliable service, thank you 1A Auto.
★★★★★February 25, 2024
Pass smog California emissions standards
For downstream in 2.2 L Camry for California emissions standards, pass smog,
★★★★★November 13, 2023
Good
★★★★★September 9, 2023
Good quality Price reasonable I will introduce a website to my friend
★★★★★April 4, 2022
Worked fine
Was fine for my 01 Camry LE.
★★★★★December 14, 2021
Perfect!
Simple install, works great and good quality!
Showing 1–10 of 21 reviews
Customer Q&A
Got a question about this part? Post it and get answers from our team.
JohnJune 15, 2021
Hello,
I have a 2000 Camry LE with the check engine light on and had the code ran at an auto store. It was recommended that I first try installing a new O2 sensor before doing any other work. ( I can't remember what the code stated but I do remember
There could be multiple reasons why you're having this particular problem. We suggest taking your vehicle to a nearby reputable shop to identify the cause. Once you know the cause, we'll be happy to see if we carry the parts and how-to videos needed for your repair.
Emma · June 15, 2021
ReyFebruary 21, 2021
Hi, have 2005 Toyota Camry 2.4L made in America. Is this the 02 sensor for Downstream bank 1 sensor 2? I also I need downstream bank 1 sensor 3. I don't think they have the same cable length. I have California emission.
Yes this is the correct downstream O2 sensor for your vehicle.
T · February 23, 2021
ClaudeFebruary 19, 2020
Who makes this sensor?
1A Auto's house brand parts are manufactured by various aftermarket companies specifically for us and built to your vehicle's exact OEM specifications. Please let us know if you have any other questions.
T · February 19, 2020
FernandoDecember 20, 2019
Is this for a 2000 toyota camry inline 4 upstream?
Thank you for your inquiry. This is not the correct fit for that model year Corolla, and we unfortunately do not carry the correct O2 sensor for that vehicle. Please let us know if you have any further questions.
A · December 20, 2019
Showing 1–4 of 4 questions
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