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
Description
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.
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.
Returns: Parts with electrical components cannot be returned once installed.
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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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
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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.
OSA61671
In Stock
Product Reviews
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3.30/ 5.010
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O2 to the rescue
Ariel-F
July 5, 2017
It worked wonderfully. Once I installed it. The check engine light went away (after driving for a while). Inexpensive. 2 sensors for the price of 1. Fast shipping to Canada.
O2 sensors
M
April 1, 2018
Worked great little delay on delivery but customer service was big help and reshipped items and got to me in the next 2 days definitely will order again from 1 auto also not only are they helpful with car parts they make videos showing you how to replace part thanks 1 a auto ill be ordering soon
Honda civic oxygen sensor pair
Scott
May 28, 2018
It was the right part and was at a great price. Will be ordering again in the future.
Wish I could give zero
H
January 7, 2019
Replaced the sensor in my car, the first 20 miles it was fine, then the car stopped accelerating and I had to get it towed to the shop.Only thing between working car and not working car was the sensor change.
The sensor may be cheaper on this site but it will cost more in the long run.
G
April 12, 2020
Good quality ,good service on time delivery.
1AEEK00173-Honda Civic O2 Oxygen Sensor Pair
David
August 12, 2020
Excellent across the board, ordering was easy,
parts arrived in time for me to do repair and get inspection.
Great experience overall, would highly recommend to anyone.
Description said it was the right part but it is not.
David
October 22, 2020
The upstream is not the right part . Upstream wires not long enough
Unsatisfied Car Parts
Ray
December 17, 2022
Website stated that it worked for my car 2005 civic lx and as soon as it got installed, it put out more codes and engine light did not turn off. Had to go to Auto Zone and buy O2 from there. It worked fine
Awesome part
Ammanda
April 30, 2024
They work great
Carlos
October 6, 2024
The sensors did not work. I had to replace them again.
Customer Q&A
Does this fit a 2005 Honda Civic lx 1.7l?February 6, 2017
Juan M
10
Yes, this will include a upstream and downstream sensor for your 2005 Honda Civic LX with the 1.7L engine.
February 6, 2017
Alex P
Do I need special socket to change downstream?April 15, 2017
Glenn C
10
No. It's easy.
April 15, 2017
Zean K
10
I changed both upper and lower sensors with an open end wrench but the O2 sensor socket would make the job easier
April 15, 2017
Winstanley F
10
Yes on my 2004 Civic. It's slightly below the upstream sensor and I didn't have any way to get to it without using a socket.
April 15, 2017
David B
10
No its not but for the price of the socket I recommend it. Locations are very tight to use a wrench a reg socket would require you to cut the wires.
April 15, 2017
Edward U
i have a 2004 honda civic dxg
Will plain dx parts fit this car? Looking at the up and down stream oxygen sensor..wa t to make sure the dx will fit dxg..
Im guessing it will..August 30, 2018
Dee B
10
This part is specific to vehicles with a particular set of options. We will need more information about your vehicle to confirm the fit.
August 30, 2018
Jessica D
Does it fit in a 2005 Honda Civic DX 1.7L?June 14, 2019
Adrian S
10
This part is listed to fit the following:
2004-05 Honda Civic DX LX L4 1.7L Upstream & Downstream O2 Oxygen Sensor Pair
June 15, 2019
Peter L
Does this fit Honda civic l.7l D176a2?December 1, 2019
Barbara D
10
Thank you for the inquiry. These O2 sensors are listed to fit 2001-2005 GX models and 2004-2005 DX and LX models.
December 3, 2019
Christa R
Does this fit a honda civic hybrid 2004 1.3L?April 18, 2021
Cesar R
10
This is not the correct part for your vehicle, but we do carry the one you need. The correct part number is:
Upstream EMS00432
Downstream : As long as your vehicle has Federal Emissions EMS00358
April 19, 2021
Christa R
Will this fit a 2004 honda civic ex?April 26, 2021
Joshua R
10
This is not the correct part for your vehicle, but we do carry the one you need. The correct part number is 1AESO00048 for downstream.
April 26, 2021
Emma F
10
I need oxigen sensor for bank 1 for 2005 Honda Civic ex
January 25, 2022
Jose L
Will this fit a 2004 honda civic ex?April 26, 2021
Joshua R
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.
April 26, 2021
Ricale A
Does this fit civic ex 2005?January 28, 2022
John D
10
No, it does not. It looks like we only carry the downstream sensor. The correct part number is 1AEOS00048
January 28, 2022
Cristina P
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