O2 sensors

[StephenCasiday]

I’m trying to figure out what sensors i’d need, everything i see online is contradicting. It says i need 2 different types of o2 sensors for upstream and downstream, and on others it says they’re completely interchangeable, and I don’t want to go and buy something and it not fit. Any tips as to what i should buy to replace all 4 sensors?

2005 Tahoe LT3 5.3 V8 4x4

 

[nonickatall]

First of all, why do you want to change all four lambda sensors?

Do you know they are defective? Normally only the two measuring probes in front of the catalytic converter are important for the engine running.

If these are defective or worn, the engine runs poorly, because the engine control measures incorrect residual oxygen values in the exhaust gas, which then leads to incorrect injection.

The probes behind the catalytic converter are just diagnostic probes that check whether the exhaust gas after the catalytic converter is different from the exhaust gas before the catalytic converter.

They are basically there to report an error if the catalytic converter is defective. They have no influence on the running of the engine and are therefore actually irrelevant.

However, measuring probes and diagnostic probes usually differ. I know this from many other cars.

 

[Joseph Garcia]

Welcome to the Forum from NH.

Lots of knowledgeable folks here who freely share their knowledge, experiences, and perspectives. Knowledge is power.

I hope that you will become a participating member in the Forum's discussions.

Pics of the truck, please.

You are already receiving sage advice from the knowledgeable folks on this Forum.

One item that reappears in the threads regarding oxygen sensors is that you should use OEM replacements whenever possible.

 

[StephenCasiday]

 

[Carolina Brown]

I did a video on what tools to use to replace them. I replaced all four on mine. They were all installed on the truck the same day at factory...if one goes bad the others will follow. Might as well replace them all if you are able to financially. Using a scan tool that can show you live data is how I was able to see that mine were bad. I had two bad ones...after replacing all four and looking at live data afterwards I saw that they were all reading the same values. I used the same sensor (Bosch) except for length of wire. I used Autozone to determine which were correct for my truck...you could cross compare to RockAuto.

See my video for which tools to use.

 

[nonickatall]

But normalvice its not necessary to replace all four. The two Sensors before the cat, are the relevent sensors for the ECM. The o2 Sensors after the cat are only for diagnosis purposes to check if the cat works or not. If this o2 sensors are bad, you probably will receive and error concerning your cat, but no bad engine running.