O2 Sensors is it Upstream or Downstream?

In this video, 1A Auto shows you how to identify an upstream or downstream oxygen (O2) sensor

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⚠ DISCLAIMER:
While 1A Auto strives to make the information provided in this video as accurate as possible, it makes no claims, promises, or guarantees about the accuracy, completeness or applicability of the content. No information contained in this video shall create any expressed or implied warranty or guarantee of any particular result. All do-it-yourself projects entail some risk. It is the sole responsibility of the viewer to assume this risk. 1A Auto is not responsible or liable for any loss damage (including, but not limited to, actual, consequential, or punitive), liability, claim, or any other injury or cause related to or resulting from any information posted in this video.

[AAuto]

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[josiahmoss]

Went and bought 2 O2 sensors; one of them cost a few bucks more ; when i got home and opened each box( different parts number) the sensors were exactly alike, only difference was the length of the wiring;

[TRUNOS]

This is one of the only videos I can find where someone actually explains upstream and downstream positioning and what they mean. Thank you

[xgtmg]

My upstream and downstream sensors have different connectors. I found out when the ones I bought off of eBay wouldn't plug in. The ad said upstream and downstream but I had two upstream sensors. Had to order some downstream sensors to finish the job.

[millyonair]

Excellent explanation! You're a GREAT communicator, bro!

[yukiostrachan]

Thank you for helping me understand that my 4 cylinder engine only has Bank 1. This video helped me immensely.

[kccodex]

Lose the music, it's pointless and distracting.

[shobud]

If the 02 sensors are different, how do you determine which one goes where ? Someone could have already put the incorrect one in the wrong place.

[fernandogalvao]

Excellent educational video. Thanks for explaining what banks are and which engines incorporate them.

[davidharrell]

This explains everything so simply. Thanks for your time and I look forward to your other videos

[xrbeokd]

Good video little late watching this but just subscribed to your guys channel hope to see more amazing videos helped me out a ton as a young guy trying to become a mechanic one day very informative straight to the point but also very detailed great job keep making these videos !

[Cougar]

This doesn't answer MY question. Are the sensing heads different? There's only one "O2 sensor" for my silverado on every parts online store I look. Is it just wire lengths that vary? If the plugs reach their harness, can I use the same part for up or downstream? Thanks.

[drosser]

Excellent question which has caused much confusion - unfortunately, you spent the entire video clarifying a different issue. Okay, so I have purchased an upstream and a downstream sensor, taken them out of their boxes, then am called away for an urgent phone call. On return, I forget which came out of which box. How does your answer help? You have described the function of the sensors well - but your question was 'how can you tell the difference?'. It does not need a video to demonstrate their location on the vehicle. Surely there should be an identifying part number stamped on the body of the unit or a tab on the cable like any other part. Can you clarify how to identify the sensors without the questionable on car comparison (bearing in mind that aftermarket units may look different anyway0

[alexchavez]

Perfect video guys, saved my a headache before my repair tomorrow

[shiddy.]

FYI ... I found out today that accidentally leaving one of the hoses on the intake near the air filter disconnected after changing the air filter will throw the exact code for this bank1 sensor2 O2 sensor failure

my torque app said the light was on for 'o2 sensor slow to respond' ... instantly fixed by fixing the disconnected hose on the side of the intake tube

if you have this code for bank1 sensor 2, first check all of the hoses that attach to the intake before digging into this O2 sensor repair - especially if you've recently had the air filter out

if writing this helps at least one person it's worth it

[joearanda]

Thank you thank you for telling me what I needed to know I appreciate it and I love your videos

[bigkev]

Man VERY excellent video & VERY informative. Thank ypu

[jmo]

Very great information thank you for the help👍🏼

[KC-vpwn]

You are the first person to tell you how to determine O2 banks. Though it now makes sense to me that the bank of cylinders with the number 1 cylinder will be bank one not everyone will make that connection in their heads.
Thank you for spelling that out to us!
Now I can go and change out my bad bank 1 sensor 2 O2 sensor and have the right one changed out!

[lotus]

Turn your engine on. Locate catalytic convertor by touching the ballooned portion of exhaust. It should melt your hand off. It has two wires fore and aft of it.