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.
OSA61216
In Stock
Product Reviews
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4.33/ 5.03
3 reviews
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No drama and no surprise fix.
Ray
July 31, 2023
Exact configuration of the 23 year-old stock sensors at a really great price. TRQ packaging was shipper proof and they arrived in excellent condition.
warren
October 5, 2024
I was sent the wrong part was supposed to be for the front but sent the back one.
O2 sensor.
Richard
December 15, 2024
Fit perfectly! Haven't have the engine light come on!
Customer Q&A
Good morning, do the nuts come with this?November 2, 2020
Linda P
10
The nuts will not be included with this assembly.
November 2, 2020
Emma F
Hello 1A Auto, I looked up both Upstream and Downstream 02 Sensors for my 97 Toyota T100. Auto, 2WD, 3.4L the error code diagnostic says bank 2. I notice no difference in P/N for either or their appearance difference. As your video suggested a possibAugust 2, 2021
James J
10
Yes, this oxygen sensor will be correct for both the downstream and upstream locations on your application.
August 2, 2021
Jessica D
Will this fit bank 2, sensor 2 for Toyota Tundra 4.7 engine?August 23, 2021
John D
10
I ordered the Oxygen sensor for 1ZZFE for 2001 Corolla. The mounting plate to exhaust did not fit. Suggest you confirm with 1AAuto. Had to modify mounting plate upon which I was informed that I voided the warranty.
August 24, 2021
WARREN S
10
Yup, fixed mine like a charm
August 24, 2021
Travis C
10
I bought it for my toyota tundra 2002 as suggested for 1AAuto, it did fit perfectly, no more check engine light.
August 24, 2021
Edwin A
10
Yes, this will be the correct downstream sensor for the 2000-2004 Toyota Tundra models.
August 25, 2021
Jessica D
is TRQ a japanese brand?February 11, 2023
John D
10
I don't believe TRQ is a Japanese brand
February 11, 2023
WARREN S
10
These are manufactured by TRQ. TRQ is a high quality, high-end name brand that we offer and back with our 1A Auto Limited Lifetime Warranty.
February 11, 2023
T I
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