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.
Is my Car a California or Federal Emissions Vehicle
O2 Sensors is it Upstream or Downstream
Created on:
Tools used
No Tools Needed
1. Determining Your Emissions Specification
Open your hood
Locate your catalyst sticker
If the sticker says "This vehicle conforms to California regulations," you have a California emissions vehicle
If the sticker says "This vehicle conforms to US EPA regulations," you have a federal emissions vehicle
If the sticker lists both EPA and California regulations, you have a California emissions vehicle
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.
Determining whether or not your vehicle is a California emissions or a federal emissions vehicle is pretty straightforward. To do this, you'll want to locate your catalyst sticker under the hood of your vehicle. It'll either be actually on the bottom side of the hood, most GM vehicles have it on the air box, and other vehicles may have it along your radiator support at the front of the engine bay.
All you need to do is see, "This vehicle conforms to California regulations." That means that this vehicle is a California emissions car. Just because you're not in California or are in California doesn't necessarily mean your vehicle will be one way or the other.
Now, our F150 has it down here on the radiator's support, right at the front of the engine bay and you can see here, "This vehicle conforms to US EPA regulations." This means that this vehicle is a federal emissions.
Now, here we have two things that are a little different. Our catalyst is located on the vehicle's air box and this vehicle conforms to US EPA regulations and California regulations. If it conforms to both federal and California emissions, it's considered a California emissions vehicle.
Thanks for watching. Visit us at 1AAuto.com for quality auto parts, fast and free shipping, and the best customer service in the industry.
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.
OSA61321
In Stock
Product Reviews
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4.90/ 5.010
10 reviews
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Service
Douglas
July 4, 2019
Overall service was great, part was the exact. Thanks
Good customer services
D
July 24, 2019
Got my product in a timely matter
Great product
jeff
December 22, 2019
Matched my oem exactly excellent price
Normally fast shipping not sure if it was holiday time or carrier being slow took in my opinion to long to get this part would have paid twice the cost at local parts stores if I new it was going to take as long as it did to get again normally fast shipping
Buick Custom LeSabre 2005 Fits
F
April 13, 2020
The video 1AAuto provided helped me put this new part in my car effectively (Buick Custom LeSabre 2005). Be warned though, the video shows an older Buick pre-2000. In the "newer" Buicks like mine, the whole engine is about 6 inches further into the car frame.
This means I had to buy a 3/8" swivel for my ratchet set in order to reach the O2 Sensor with a tool. It is doable on the newer Buicks, you just need an extra piece. Swivels can be bought at a typical hardware store for around $15.
Thank you 1AAuto for listing this replacement part at a lower price than other companies. Considering I am an English Teacher and always trying to cut corners for money, I appreciate it.
Upstream oxygen sensor
Matthew
August 11, 2020
This oxygen sensor fit and works great on my 2006 buick lucerne cxl v6. 100% recommend
I will ALWAYS use 1a auto!
Matt
November 30, 2020
These o2 sensors came in perfect condition packed with plenty of bubble wrap to make sure they werent damaged and worked efficiently. They even went as far as to put a little bit of anti seize lubricant on the threads of each sensor! Very nice touch! I love this company and their dedication to providing the BEST of the best! Keep up the great work guys!
Simone
April 19, 2022
Exactly part needed n fitted my car
Kenyata
April 26, 2022
1A Auto always come through.
Just what the Buick needed
Bob
June 23, 2023
Easy to install and took care of the problem.
Alejandro
August 22, 2024
Very good
Customer Q&A
Do u have the downstream?July 19, 2017
Dianna K
10
What is your vehicle information to provide the accurate downstream oxygen sensor?
July 19, 2017
Alex P
Is this a wideband sensor?March 11, 2018
Diane C
10
No
March 11, 2018
FarLFT .
10
Al 💯💯
April 8, 2021
M A
Is this OEM?February 20, 2020
T E
10
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.
February 20, 2020
Peter L
10
NO MADE IN CHINA THE THREADS WERE OFF WOUD NOT SCREW IN
February 21, 2020
Robert M
Customer service
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