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Hey there!

The check engine light came on in my '04 Honda Civic EX.

I hooked up a code reader and it came back with the P0134 O2 sensor fail on Bank 1, Sensor 1.

I did some searching on the net, and couldn't really find a clear answer as to the correct location of the Bank 1, Sensor 1 location on the '04 Civic.

I'm not sure if it's the sensor that sits near the engine block, or if it's the sensor that's near the catalytic convertor.

Anyone know where this might be? Thanks!

 
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#1 is ahead of the cat, in the pipes between the head and the cat. First sensor in the exhaust stream.

Sensor #2 would be in or after the cat.

 
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out of the 8/9th gen section and in to the correct 7th gen section! Moved!

 
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Dangit, I missed that again LOL

 
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So is that underneath the car or in the engine?

Also is that considered upstream or downstream?

 
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Have you located all two sensors on the car yet?

 
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See this diagram. Sensor 1 is Item 7, Sensor 2 is Item 8.

 
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That's an LX setup. OP has an EX.


That means it's part #19, and the pic makes it as clear as mud.

 
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Well, I have located the one that is illustrated as item #7 in crxmanpat post.

But from your illustrated post, it looks like I'm gonna have to get under the car.

I'll hop under there and take a look and see if there is one there.

 
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LX has the cat mounted in the exhaust manifold (first parts pic from Pat), whereas EX has the cat located further away from the engine, under the car (2nd parts pic from me).

The sensors are in different places on each version, but they are always in the same relationship to cat placement, i.e. primary or secondary, ahead of or in/behind the cat.

HTH

 
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And FYI the front sensor is an A/F sensor, not an O2 sensor (even though it is called that). They look about the same, do the same job, but the internal workings are entirely different and cannot be substituted one for the other. The computer is not the same either.

 
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Ahhhhh, ok.

Gotcha.

So, I am looking for an EX upstream O2 sensor.

And the location is under the car for the 04 EX.

I think I get it now.

Thanks for all your help!

 
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Erm....You sure you got it?
You said your car is an EX in the first post.



Find your cat, then locate the two sensors.

 
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DAP! Yes, I meant EX, not LX. Sorry. I edited my previous post.