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.
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.
Product Reviews
Loading reviews
4.06/ 5.017
17 reviews
5 Stars
4 Stars
3 Stars
2 Stars
1 Star
10
4
0
0
3
I ignorantly ordered the upstream instead of the Downstream
Gregory
January 26, 2018
Return was easy and the right part was shipped right out.
parts
J
March 22, 2018
part was correct and received quicker than they said/ well done
O2 sensor
W
March 14, 2019
Great price received it fast
G
April 5, 2019
Order delivered promptly. Satisfied customer
Works perfect
P
July 23, 2019
I purchased the Oxygen ratio gas pressure sensor for 2006 Toyota Sienna and fast delivery to me on time, it works real good ... I do Recommended to everyone to do so......!!!
Not an exact match
Y
August 21, 2019
I am a novice in repairing cars. The tip of this sensor did not match original. The plug outlet was a perfect fit.
I installed this sensor easily following the A1 instructions once I decided that the tip, though shaped differently, should work just as well.
Perfect fit
Leon
December 30, 2019
Fast shipping quality part best price
O2 Sensor
F
September 12, 2020
I ordered an O2 Sensor for a Toyota Sienna was the right fit and fixed my issue i was having. Thank You.
Perfect
J
September 22, 2020
Exact fit no engine codes
Works just fine. 1/3 cost of OEM.
A
February 19, 2021
Was a little hesitant to use this on a Toyota, as I heard they only like OEM branded air/fuel ratio sensors. But OEM sensor costs 3x as much. I have used 1aauto parts before and they worked fine, so I thought I would try. Turns out it works fine. Code has not returned and car is now passing emission tests. Would absolutely recommend if you don't want to invest in OEM parts for an older car.
Poor quality
Jeff
July 31, 2021
Failed right after it was installed.
??
Jerry
November 17, 2021
So far no problems!
Ive lost money on labor and cost!
Jerome
March 8, 2022
Codes came back on with the sensors I purchased from 1A Auto. I purchased Denso sensors and the lights never came back on.
Returned
David
March 13, 2023
It didn't work. The check engine light was still on. It has been a month since I returned this and I haven't received a refund.
Jose
November 26, 2023
It works perfectly for my vehicle thank so much,fast shipping and great customer service and product intact.
Darwin12
Carlos
February 7, 2024
I love it is good quality my truck running perfect I can recommend to others to buy
Relief!!!
Santiago
September 22, 2024
I ordered the part because I needed an emergency replacement. I had just received an A/F Sensor from E Bay and it was a DUD! Bad part and I couldn't get a refund. Very Disappointed!! Thanks to 1A Auto, I received the Sensor and it worked!!!
No problems thus far. So thankful.
Customer Q&A
my car is front wheel drive will this item fit my camry?December 9, 2017
J A
10
This will fit your FWD model as long as the engine size and placement on the vehicle matches our fit chart at the bottom of our page.
December 11, 2017
Alex P
is the front sensors the same as bank 2?February 24, 2023
Robert W
10
These Sensors are located for the Front and Rear.
February 25, 2023
Jean O
Will this fit 2018 camry 2.5 L xse ?November 26, 2024
Orlando R
10
No, this part is specific to 2018 Toyota Camry models with a V6 3.5L engine.
November 26, 2024
Jessica D
Customer service
877-844-3393
Monday - Friday 8:00am - 9:30pm ET Saturday - Sunday 8:00am - 4:30pm ET
Toyota is a registered trademark of Toyota Motor Corporation. 1A Auto is not affiliated with or sponsored by Toyota or Toyota Motor Corporation.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.