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.
OSA61231
In Stock
Product Reviews
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4.30/ 5.023
23 reviews
5 Stars
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1 Star
17
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Great!!!
Loretta
June 22, 2018
Great price and fit perfectly! I would do business with you again. Matter of fact my my dad ordered the same part because it was exactly what we needed for a good price! Thank you!!
Wrong part- return was a hassle
bruce
August 21, 2018
The A1 staff was friendly and helpful but the return for their mistake was a hassle. Again the staff was helpful but I believe their return policy fails to meet basic customer service. I Ordered the part as stated on their website but it wasnt the right part. A1 staff admitted this part was a problem before but I guess the website hasnt been updated. They agreed to return my money but only after I returned their wrong part. The part was like $50 dollars and took a full week to get; I ordered the correct part from a comparator and received it in two days. A1 sent me a UPS return label but it wouldnt print out so I had to drive it to the nearest UPS store 25 miles away. I now have more time and money in this 02 sensor then I paid for it. I guess I expected to be credited sooner and maybe just keep the part instead of having to spend so much time/effort returning it. For the record I cant use the part so keeping it wouldnt do me any good other then avoiding all my running around. After a
Perfect boot on fit for Tundra
X
November 25, 2018
Perfect bolt on OEM fit for my Tundra, cable was a little longer but a zip tie fixed that right up. Check engine light hasn't come back since, great deal of you ask me!
oxigen sensor
Hector
March 22, 2019
Excellent quality sensor perfect fit with out any modifications very happy
Perfect fit
Ralph
June 15, 2019
Check engine light was on, code was one of the 02 sensors. Local parts store was 185.00 for just the one! Online, found BOTH delivered for 100.00!
Easy install, drove it 30 miles, light went off, passed inspection!!!
Direct replacement is right
S
June 18, 2019
Had to replace factory o2 sensor ( before CAT) due to blown head gasket ( coolant in exhaust system). Out with the old, in with the new, plug in and go! Works perfectly so far and saved a TON of $$$. Picked this up from 10s for about $70 after being quoted 190 plus tax at AutoZone.
I'm Way Happy.
03 Toyota Tacoma Prerunner V6 3.4l
Very pleased
G
July 2, 2019
Quick delivery. Proper fit. No more check engine light on. Will definately shop 1A in the future
O2 sensors
Benjamin
August 30, 2019
Parts were exactly the ones I needed at an amazing price!! At least half the price of anywhere else I was able to find them! Received them three days after ordering them, which was two days earlier than predicted to be delivered. Operators very friendly and helpful, would definitely recommend them to friends and family!! In fact I already have!! Thanks so much 1aauto!
Jennifer
September 3, 2019
Always get what we need
Exactly what I needed
B
September 10, 2019
No issues in the install.
01 tacoma O2 sensor
Edwin
November 10, 2019
Product arrived as scheduled an fit like a glove, installed by dis backyard brokanic without a hitch, no problems, once I got the rusted nuts off, thank you 1a auto.com
Upstream O2 Sensor Works
M
December 20, 2019
Part came as shown and was a replacement to the OEM part. The ear plate on this part is approximately 1 mm thinner than the OEM ear plate. Not a big deal usually, but I needed to add a washer between the ear plate and the nut because the threaded stud was rusted at that depth.
The signal seems to be valid and the ECU is reading the sensor fine.
Pesky light is no longer on
gayla
December 23, 2019
Thank you for having the upstream O2 sensor I have needed to replace for a while. Now the light is off and she is humming along nicely
Fast delivery
D
April 9, 2020
Fast delivery and the right part. Good price too
O2 Oxygen Sensor
Randy
April 9, 2020
I would recommend 1AAuto to anyone looking for great parts and great prices. The O2 Oxygen Sensor works as advertised. Perfect fit and corrected my problem.
Zero if I could
Seth
June 27, 2020
Absolute garbage. Had a check engine light since replacing. Keepa popping up every 2p miles. Even after trying to call and email to get my money back this company wont reply. Avoid
No good
Chase
December 30, 2020
Not worth it. Worked for about 3 months then failed (verified with olm reading)
Happy customer
Vernon
June 14, 2021
Sensor was correct fit and worked perfect
Same as OEM
Trevor
October 25, 2021
Great worked perfect, check engine light hasnt been on since I installed it
I would buy from somewhere else
Lester
October 27, 2021
It didnt work. Unplugged the battery, waited 15min, then installed the O2 Sensor. Started the car and it check engine light still on and the exhaust stinks even more. Waste of $75. Spent a little more on Denso Sensor for $105 at auto zone and it worked perfectly.
Javier
December 25, 2021
The sensor fit like the original part. The engine is running like before the original sensor went bad.
Klint
September 13, 2022
Fits great. Cost less than auto parts store.
Awesome
Eric
December 5, 2022
Love the price and free shipping......
Customer Q&A
will this part work with a manual transmission?July 3, 2016
Greg S
10
These are only engine and emission specific. Transmission type is not applicable for this.
July 7, 2016
Brian F
10
Yes.
July 5, 2017
Ariel-F M
10
Yes.
September 16, 2017
R A
10
Yes
October 3, 2018
D O
10
Yes
February 23, 2019
Derrick M
Will this fuel air sensor work on California emission ?February 2, 2019
Rex A
10
It will be compatible with California emission vehicles.
February 2, 2019
Corey M
Is this the part that I need for code throwing p0125?? 2001 Toyota Tacoma 2.7November 8, 2019
Brandon W
10
Hello Brandon!
Thank you for your inquiry. The code you are referring to is an issue with insufficient coolant temperature. It is possible you may need to replace the Engine Coolant Temperature Sensor, however, we always suggest having the vehicle professionally diagnosed prior to any repairs to ensure the correct parts are being replaced and there is not a larger issue. We hope this helps you out and please let us know if you need any further assistance, thank you!
November 8, 2019
Jessica D
10
Brandon, a P0125 is a generic engine code but is "Insufficient Coolant Temperature For Close Loop Fuel Control." A faulty Oxygen sensor would not likely throw that code. According to Repair Pal, a P0125 is normally associated with "Defective Engine Thermostat; Defective Engine Coolant Temperature Sensor; Defective Intake Air Temperature Sensor; Defective Cooling System; Low Engine Coolant; Dirty Engine Coolant, causing incorrect Coolant Temperature Sensor readings; Defective, or always running Engine Cooling fan(s); Probably need more diagnosis to isolate. Bottom line: An oxygen sensor is probably not want you want.
November 8, 2019
S K
10
It worked for me but mine was a 3.2 v6 but they are probably the same o2 sensor.
November 9, 2019
C H
How long is cable?March 3, 2022
Ruddy Q
10
14 inchs
March 3, 2022
L L
10
Overall Length: 17.72 in
March 3, 2022
Andra M
Customer service
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