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.
OSA61237
In Stock
Product Reviews
Loading reviews
There are no reviews for this item.
Customer Q&A
Does this sensor listed work for both/either upstream and/or downstream?November 3, 2018
Victor F
10
Only for downstream, but good luck with the fit, the one I bought did not fit and ended up getting one at whinchester auto a Denso o2 sensor works perfectly
November 3, 2018
B R
10
no
November 3, 2018
Thomas D
10
This will fit either the upstream or downstream location, but it depends on your model. What is your full year, make, model and engine size?
November 5, 2018
T I
10
2006 Honda Ridgeline
February 3, 2022
Reuben A
Would this fit bank 1 sensor 2 for 2006 Acura TL?December 3, 2021
John D
10
Yes, this part will fit your vehicle as long as you have an automatic transmission.
December 3, 2021
Emma F
10
No
December 6, 2021
Jaime Z
will this fit bank 1, sensor 2 Odyssey 2007 V6 3.5L?December 20, 2021
Kev N
10
This will fit the Downstream front location.
December 20, 2021
Andra M
is it good for upstream 2.4l 04 honda accord?March 12, 2022
Carl A
10
Currently, we do not carry this part for your vehicle. We're always updating our inventory so please check back soon!
March 12, 2022
Cristina P
Does this sensor listed work for both/either upstream and/or downstream on a 2003 Honda Civic Hybrid 1.3L?October 12, 2022
Gerardo G
10
This is listed to fit:
2003 Honda Civic Hybrid L4 1.3L Built Before VIN 3S020169 downstream.
October 12, 2022
Kelly S
Does oxygen sensor upstream and downstream oxygen sensor fit for 2005 Acura TL car?December 26, 2022
Afton P
10
This will only be able to fit for the downstream.
December 29, 2022
Emma F
How to install upstream oxygen sensor ?August 25, 2023
Hosea S
10
i can't write a good in English but go to youtube, is the best way,good luck.
Is this compatibale with honda civic es5 2003?February 6, 2024
Madusanka K
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.
February 6, 2024
Kemal S
Customer service
877-844-3393
Monday - Friday 8:00am - 9:30pm ET Saturday - Sunday 8:00am - 4:30pm ET
Acura is a registered trademark of Honda Motor Co., Ltd.. 1A Auto is not affiliated with or sponsored by Acura or Honda Motor Co., Ltd..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.