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
How to Replace Downstream Oxygen Sensor 2003-2007 Honda Accord
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.
Tools used
1/4 Inch Ratchet
Torque Wrench
Gloves
Flat Blade Screwdriver
O2 Sensor Socket
1/2 Inch Ratchet
Jack Stands
Wheel Chocks
3/8 Inch Drive Ratchet
Floor Jack
Trim Tool Set
Safety Glasses
Product Reviews
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Oxigen sensor
B
November 21, 2018
That was good price ,but I received 2 oxygen sensor wrong
great !!!
Jonhy
December 13, 2022
great !!!
Scott
March 6, 2024
They work fine without issues. Use the correct tools to remove them to save you the hassle.
My-Number
October 12, 2024
Parts worked great, highly recommend.
O2 sensors
TIM
November 14, 2024
These fit perfectly easy to install, the video is very helpful and everything's working out perfect.
Customer Q&A
Are these only downstream or they can be used upstream as well?January 14, 2019
Khaira-Nisaa H
10
Depending on your application this item is able to fit for either.
January 14, 2019
Emma F
10
These sensors will be for downstream only and will not be compatible for the upstream slots.
January 14, 2019
Corey M
10
I believe the upstream and downstream sensors are different.
January 14, 2019
Keith S
10
I was satisfied only thing I didn't like is that they sent the wrong part but they corrected it
January 14, 2019
E D
10
They can be used either or
January 15, 2019
E S
Is this only for downstream or does it also fit upstream?January 14, 2019
Khaira-Nisaa H
10
Depending on your application this item is able to fit for either.
January 14, 2019
Emma F
Is this pair of sensors considered secondary? After cat front? After cat rear?June 30, 2020
Latasha J
10
This is a pair of downstream oxygen sensors. The downstream location is between the catalytic converter and the tailpipe. Thank you for the inquiry!
July 1, 2020
Andra M
I did not see a question for engine size regarding my application. I do not want to order parts if I cannot specify all pertinent information. I have a 2005 Honda Accord with a 2.4 liter L4. The part that was displayed was for a V-6. Are they same paAugust 25, 2020
Leonard F
10
Thank you for your inquiry! These parts are specific to models with a V6 3.0L engine and would not be compatible with a 2.4L engine. We carry the downstream sensor under part number 1AEOS00058 that would be compatible with your engine size. We do not carry the upstream. Please let us know if you have any further questions, thank you.
August 25, 2020
Jessica D
oxigen sensor O2S bank 1 sensor 2 honda odyssey 2005 need buy parts ? /December 11, 2021
John D
10
Yes, this part will fit your vehicle. These sensors will be compatible with Bank 1 Sensor 2. If you need just a single one you can look up 1AEOS00104
December 11, 2021
Cristina P
Which one of these oxygen sensors OSA61288, OSA61237 is bank 1 downstream?December 7, 2022
David C
10
That would depend on your application. Can you reply with the year, make, model and engine size?
December 7, 2022
T I
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