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.
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O2 Sensors is it Upstream or Downstream
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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.
OSA61188
In Stock
Product Reviews
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3.91/ 5.023
23 reviews
5 Stars
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14
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no problems
Gordon
February 21, 2017
Quick delivery to my house, fit perfect, no problems installing.
Good price
o2sensor the bomb
jimmy
March 8, 2017
The best for the price cant beat works as Tony the tiger said GREAT!!!!
Imad
March 19, 2017
its good works just like the genuine and save a lot money
Low cost/works great
D
August 24, 2017
It was the lowest cost I could find, and is working great!
O2 sensor not an a/f sensor! Not sure if it is listed incorrectly for all vehicles though.
Ross
September 11, 2017
This is a perfectly functional O2 sensor, only problem is that the application it is listed for requires an air/ fuel sensor. These are 2 different types of sensors with incompatible outputs. The tricky thing here is most a/f sensors are 6 wire.. this one is 4 so it will physically install. However you will get a MIL and surging etc. (If you own a Civic, other cars listed can't speak for everyone). I'm a professional mechanic and kind of thought the price was too good to be true as Honda sensor is over $200. When you look at the waveform it's clearly a switching O2 sensor though so it will not work in the Honda s or Subarus listed on the website.
Works ok but it's not the upstream sensor
ben
September 23, 2017
I ordered to replace a faulty 02 sensor in my 2004 honda civic ex. When it came in I went to go install it and the connector was wrong. On the site it says the upstream and downstream have the same connector but that is incorrect. I ended up having to cut and splice the wires onto the old connector. Other then that it seems to be working fine and it got rid of my P0143 code.
Large grommets.
Jose
October 13, 2017
Had trouble inserting the insulator grommets into the metal tabs (too big). Had to remove the wire holding brackets to reshape the folding ends.
Faulty / wrong part
R
October 23, 2017
This part came at the time they said it would however the part was either faulty or not the right part for the car. According to my mechanic this is a normal O2 sensor and the 2004 Honda Civic upward sensor should be the air fuel ratio sensor. However my check engine light came right back on I did get a refund for this part but I will not get the money back for the labor cost that I spent on it
S
February 8, 2018
product was as stated and installed easily. The only issue was that the clip rubber mounts were larger then stock and had to pry the frame clips larger to fit. Great price and fixed the problem.
Nice
L
November 1, 2018
1A Auto very good prices customer service is very helpful very nice place to get your parts and get the best help ever ...Thanks 1A Auto and customer service
Good Product!
Braiden
January 14, 2019
Vehicles PCM (Computer) showed O2 sensor code. Car ran with misfires. This part fixed the issues.
Subaru Baja front end overhaul
Ahmad
October 9, 2019
Top notch parts OE quality and timely delivery
Oxygen sensor
Kennedy
November 17, 2020
I bought this sensor and I made my car feel brand new.
HO2S replacement
Colin
April 26, 2021
Got the part for $100 less than all local stores. Can't beat that with a stick! Car's fixed too.
Thank you!
Awesome
kirk
October 3, 2021
Working well and a great value. They are easy to install.
Faulty sensor
Phil
January 10, 2022
I wanted to wait a few days of driving my vehicle before reviewing this item and I am glad that I did; I have driven for about 100 miles or so and the CEL came on today. Checked it with my scanner and code P0030 came up. Sensor 1bank 1. That is the sensor that I just replaced, the one I bought from you. It is faulty so what do you propose to do to rectify this situation? I await your response.
Jose
January 13, 2022
Yes my experience was very good I am recommended 1auto because I find what need whiteout any problem and price is good of the products and whiteout shipping charges ????
O2 Replacement Sensor
Caleb
March 10, 2022
Fit like a glove and fixed my problem. Delivered quick.
Juan
May 1, 2023
Fit perfect and got rid of the check engine light
When cats bad loose factory 5,500 everywhere revs 500 revs 1000 at times
Chad
July 17, 2023
2001-2003 subaru outback limited 2.5I Baja legacy models what's weird I'll tell you every thinks everything's fine guess what it's odd actually check engine light off right A++ their the engineer made this car accidentally about that only 1 sensor I'll tell you that the cats will oddly strange keep working fine Houston we have a problem their not even though magically they are working too alot of mechanics out their post cat 1 is the fix
Great product!
Garrett
November 17, 2023
Works perfectly and cleared out my CEL!
O2 sensor
Adam
November 26, 2023
Had in for 2 weeks. Now check engine light is on for O2 heater circuit malfunction.
Kevin
March 18, 2024
Works great,. Check engine light was on and I took a guess at the problem and ordered the sensor, took about 45 minutes to change out and the next day the check engine light turned off.
Customer Q&A
Will this after market sensor really work as the high price sensor for my2004 honda civic ex ?August 12, 2018
Carl E
10
These are brand-new, aftermarket parts that are made to the same specifications as the originals and their performance is the same as the original. This part is correct for your 2004 Honda Civic EX L4 1.7L Upstream (Air / Fuel Ratio) O2 Oxygen Sensor.
August 13, 2018
Elesban A
10
Will this work for a 2004 Subaru Impreza RS?
May 19, 2022
John D
I want to know if this product fit 2005 civic ex?October 6, 2018
R O
10
This is able to fit if you have a L4 1.7L.
October 8, 2018
Emma F
Will this work on a 2003 Forester x?February 7, 2022
Douglas R
10
Yes, this part will fit your vehicle as long as you have a H4 2.5L Upstream.
February 7, 2022
Emma F
Customer service
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