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.
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
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.
Quality Tested - built to a strict level of product standards.
Item Condition:New
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.
FREE Shipping is standard on Orders shipped to the lower 48 States (Contiguous United States). Standard shipping charges apply to Hawaii, Alaska and US Territories. Shipping is not available to Canada.
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.
OSA62855
In Stock
Product Reviews
Loading reviews
5.00/ 5.025
25 reviews
5 Stars
4 Stars
3 Stars
2 Stars
1 Star
25
0
0
0
0
Money Saver
D
July 8, 2019
Well these work great on my 07 Escalade. I didnt have to pay an arm and a leg through a local auto parts store or dealer for them either. The socket I bought with them is a quality socket also, works great for removal.
B
November 20, 2019
Parts came in fast and fit perfectly. Will order again
Great product! Fast shipping!
K
August 6, 2020
Product arrived very fast!
Great quality!
Price was better than other websites!
I will purchase from them again!
Look just like OEM!
Steven
March 19, 2021
I previously installed some cheaper ones that didn't work. So I ordered these and they work great. I would recommend these. Great price and fast shipping. I should have ordered these first time because I had to do the job twice because of other cheap ones. I learned my lesson!
Oxygen sensor
G
March 24, 2021
Great product this part fixed my problem I would recommend it
Great parts
Nicolas
May 26, 2021
Was great quality I would definitely buy them again field a v8 Chevy
great job
cory
September 18, 2021
they looked great in the packaging 2 went in easy 2 werent that much fun but thats the car .seems to be working great i would buy them again
Thomas
October 14, 2021
Awesome parts fits perfectly. No hassle fast
Delivery finished with in a hour.
Thank you ??
Great
Guillermo
January 19, 2022
O2 sensors
Good product
Edward
January 12, 2023
My 2007 Chevy avalanche is running perfect. The 4 new 02 sensors has this baby purring along in 4 cylinder most of the time. Thank you 1AAuto.
Excellent value
Captain
January 22, 2023
All 4 items worked as designed to clear the O2 sensor codes from my truck!
Great site
Roger
February 3, 2023
Great place to buy parts and they have the right parts
Joseph
March 24, 2023
Worked OK
02 madness
Stephen
August 13, 2023
Simple installation socket really necessary
Ryan
August 28, 2023
Since install have had no issues and they were a direct fit
Anthony
February 18, 2024
My ESCALADE ESV IS RUNNING SO MUCH BETTER THAN EVER BEFORE THIS THE REAL TRUTH .IM MORE THAN SATISFIED
Big $ savings over local parts store! And I mean big!
David
March 24, 2024
Excellent part and price! Exact match and quality connectors. O2 sensor is pre-lubed with anti- seize saving you time and risk of fouling the sensor. For all the years I have changed O2 sensors- and learned new foul words to describe the process- the video was a huge help!
Wires
Rafael
May 24, 2024
Great quality
Quality Part. Would recommend
Brian
June 8, 2024
This item arrived quickly and were an exact replacement. I have been very satisfied with the TRQ brand. I would definitely recommend.
Having an oxygen sensor socket would have made the install a little easier. The sensors in front of the catalytic converters are difficult to get a wrench on.
I am beyond pleased with 1A Auto. I will order more parts soon.
Marcus
June 9, 2024
I love the fact that 1A Auto sells great quality parts and the shipping is extremely fast. If they do not have oem parts for your vehicle, they definitely have parts that are more than capable of getting the job done with warranties. I also love the fact that they give tips before installing auto parts as well.
Clyde
June 18, 2024
I ordered these after my truck started skipping and acting erratically. Codes for O2 sensor upstream. Ordered these and fit perfectly. Changed all 4 and truck runs awesomely. On time and great price.
Good
Erick
June 29, 2024
Good fit no issues
Paul
August 22, 2024
Works perfectly
Great quality, good price
Brenden
October 7, 2024
Fixed my o2 sensor code i had, Had a check engine light for a while and decided to buy some Amazon O2 sensors and they never fixed my problem code, installed these O2 sensors from 1aauto and my code went away after driving around about 50 miles and i passed my smog check. So buy quality parts the first time and you'll get quality results and save money
Nichilas
November 9, 2024
Very good
Customer Q&A
Is there anti-seize already applied to parts?June 8, 2019
C L
10
These will not come with anti-seize already applied.
June 9, 2019
A C
will this work in my 07 Silverado 1500 classic 5.3 vortex ?April 12, 2020
Jim N
10
I used it on a 2007 Cadillac Esv. I would think that it would work but don't know for sure.
April 12, 2020
Lloyd A
10
These are not the correct part for your vehicle, but we do carry the ones you need. The correct part number is: Upstream 1AEOS00203
Downstream : 1AEOS00204
Please let us know if you have any other questions. Thank you!
April 12, 2020
Christa R
will this work on 06 silverado with the 5.3 engine?June 23, 2020
Adam M
10
This part will not fit your vehicle. We may have a part that is listed to fit.
Please enter your vehicle's year make and model in the search bar at the top of the page. This will display parts guaranteed to fit your vehicle.
June 24, 2020
T I
Will this fit 2007 chevy tahoe 5.3L?July 7, 2020
David K
10
Thank you for the inquiry. Yes, this set will be correct for the 5.3L. Please let us know if you have any additional questions.
July 7, 2020
Curtis L
Will this fit 2007 GMC Yukon XL Denali 6.2L 1500 ?October 1, 2020
B A
10
This part will not fit your vehicle. We may have a part that is listed to fit.
Please enter your vehicle's year make and model in the search bar at the top of the page. This will display parts guaranteed to fit your vehicle.
October 1, 2020
T I
Do you have a 4 piece o2 sensor set for a 2007 gmc sierra classic with a 5.3 flex fuel or does this set work?October 12, 2020
Frank F
10
Currently, we do not carry this part for your vehicle. We're always updating our inventory so please check back soon! If you have any other questions, let us know.
October 13, 2020
Emma F
10
Which is upstream
August 18, 2021
John D
Which one is for upstream and which is for the downstream?November 14, 2020
Alan B
10
Thank you for the inquiry. This would depend on the vehicle in which you are installing these into. If you can provide the year, make, model, and engine size of the vehicle you are needing these for we can let you know which is which.
November 14, 2020
Curtis L
10
Hello, We would happy to tell you the part numbers and location, could you provide your full vehicle information, please?
October 4, 2021
Ricale A
Will this fit 2007 chevy suburban 5.3L flex fuel? And how I know which ones are upstream and downstream??April 5, 2021
Caleragto C
10
Yes, according to the information you provided, this part will fit your vehicle. When you receive them they are labeled with the corresponding part number to show which side the part belongs to.
April 5, 2021
Cristina P
This works on 2007 GMC Sierra new body style correct? See it says 2007 GMC Sierra classic 4.8.June 2, 2021
Adam C
10
These will not fit on the new body style, only the Classic for a 2007 model year.
June 2, 2021
T I
Will these work on a 4.6 L?August 15, 2021
Consuelo V
10
This will depend on the year, make and model of your vehicle.
Please enter your vehicle's year make and model in the search bar at the top of the page. This will display parts guaranteed to fit your vehicle. Just be sure to verify all of the information shown in the Vehicle Fit tab before ordering.
August 16, 2021
Cristina P
Are these the same sensors as the 15150& 15898 sensors?September 7, 2021
James M
Which one is upstream and downstream by part number ??October 2, 2021
Thomas T
10
Hello, we would be happy to assist you with that, could you provide your VIN#, please?
October 2, 2021
Ricale A
This will fit to 2007 Chevy Silverado classic 2500 6.0L?December 2, 2021
Marcos M
10
This part will not fit your vehicle, but we may have a part that is listed to fit.
Please enter your vehicle's year make and model in the search bar at the top of the page. This will display parts guaranteed to fit your vehicle. Just be sure to verify all of the information shown in the Vehicle Fit tab before ordering.
December 2, 2021
T I
Will this fit an 07 gmc sierra 2500 with a 5.3 engine?April 6, 2022
Alan S
10
This is not the correct part for your vehicle, but we do carry the one you need. The correct part number is: 1AEEK01252 for the upstream and 1AEOS00114 for the downstream
April 6, 2022
Cristina P
Will this fit 2006 chevy tahoe 5.3 flex fuel 4wd?June 25, 2022
BOB S
10
Hello, this kit is listed to fit 2006 Chevrolet Tahoe V8 4.8L Upstream & Downstream
June 25, 2022
Ricale A
which is the upstream and down stream for a 2007 Chevy Tahoe?September 29, 2023
Donnell S
10
When I purchased them I went on which plug was different.
September 29, 2023
William H
10
The items will be labeled by each individual part number once they are received. There will be two of OSA61702 which are the upstream. And two of OSA61214 which are the downstream.
September 29, 2023
Meghan R
Will these fit in the 4.3 V6? The parts description says yes, however at least one staff comment says these are for 4.8L only...July 31, 2024
Eric W
10
These will not be able to fit for a V6 4.3L.
July 31, 2024
Emma F
10
no
August 22, 2024
Paul P
Are these sensors heated?August 25, 2024
John P
10
Yes, the sensors will be heated.
August 26, 2024
Jessica D
Customer service
877-844-3393
Monday - Friday 8:00am - 9:30pm ET Saturday - Sunday 8:00am - 4:30pm ET
Chevrolet is a registered trademark of General Motors Company. 1A Auto is not affiliated with or sponsored by Chevrolet or General Motors Company.See all trademarks.
Enter Vehicle Year Make Model
Specify your vehicle's year, make and model to guarantee fit.
Year
Make
Model
Options
Drivetrain
This part doesn’t fit a . Select from parts that fit.