02 sensor location

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daMicr0wav3

New member
Easy question guys but I've done so many searches with no specific luck.....hope you can help, I'd like to do this this week.

I've got the check engine light on, took it to Autozone, they said it was 02 sensor at bank 1, sensor 1. I bought the 02 sensor & want to change it out, but where can I specifically find it (no super mechanically inclined, but I think I can do the job). Also, any tips/tricks?

Thanks guys
:nerd:
 
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O2 sensor is in the exhaust. There's one before the cat and one after it. Get a small torch and heat the sh*t out of the nuts, get them glowing red, then they'll come right off. 12mm wrench or socket. If the nuts are real bad you'll need to use vice grips. Make sure the new sensor has a new gasket, other wise you'll need to buy one. If the nuts need vice grips to get them off, buy two new ones too. Before you buy the sensor, double check to see if you have Cali or Federal Emissions. (the sensor is different depending on which you have)
 
yeah, all good advice from pitbull. But, being that your in Fl, I doubt you'll need to heat up anything. Rust is probably not a big issue for you if your truck was always in Florida.

So, basically. Make sure you have the right O2 sensor. If it's a denso like it should be then it does come with a gasket. And you can almost certainly reuse the two (10mm? 12mm?) bolts that come off the old one.

Really simple task. Two bolts, One electrical connector. 15 minutes tops.

Oh yeah, and sensor 1 bank 1 will be the front O2 sensor. So, on the exhaust pipe in front of the catalytic converter.(closest to the engine)

one more oh yeah. If you feel so inclined some antisieze on the bolts during reassembly isn't a bad idea.
 
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In your case, you can ignore the Cali/Federal part...that did not exist in '98. But check out the state of the nuts...if you are by the coast salt corrosion is a factor. If they are corroded get new ones from the dealer (Part # 90179-08059 or find two M8-1.25 stainless nut somewhere).
 
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Don't use a sledge hammer when a rock hammer will do. First, try a 6 sided 12mm socket on the nuts. If they won't budge or feel like they'll round off, shoot the works with some PB Blaster and let it sit a while and then try it again. If they are in bad shape, buy some new nuts to replace them with and use some anti-sieze on them when you put them back on. Mine were rusted pretty bad and wouldn't come off with a standard/cheap type 12mm socket, even though I hit them with PBB 24 hours prior and 2 hours prior to trying to remove them. I let them sit another day and borrowed a 6 sided socket and they came right off. But I put new stainless nuts back on and smeared them with anti-sieze.

I hate to ask what brand and how much you paid for the sensor. Denso is the recommended brand and they can be had online fairly cheap. Bosch sucks and can cost up to 3 times as much over the counter.
 
T4R_Finally said:
Don't use a sledge hammer when a rock hammer will do. First, try a 6 sided 12mm socket on the nuts. If they won't budge or feel like they'll round off, shoot the works with some PB Blaster and let it sit a while and then try it again. If they are in bad shape, buy some new nuts to replace them with and use some anti-sieze on them when you put them back on. Mine were rusted pretty bad and wouldn't come off with a standard/cheap type 12mm socket, even though I hit them with PBB 24 hours prior and 2 hours prior to trying to remove them. I let them sit another day and borrowed a 6 sided socket and they came right off. But I put new stainless nuts back on and smeared them with anti-sieze.

I hate to ask what brand and how much you paid for the sensor. Denso is the recommended brand and they can be had online fairly cheap. Bosch sucks and can cost up to 3 times as much over the counter.
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Thanks guys -all great info. The bolts aren't bad, like mentioned above it's been in Florida so it shouldn't be a problem getting off. And yes, it is a Bosch, was $109 but my friend had an employee discount for 25% off, OEM fit, so I couldn't pass it up.

My original question still stands though, which O2 sensor is bank 1, sensor 1 and where is it located exactly, so I know I'm changing out the right one!! :) And I thought there were 4 O2 sensors??
 
You sure it was a coil and not the O2 sensor? Bank 1, Sensor 1 doesn't make sense for it being an O2 sensor. I could be wrong, I'm no expert but sound right to me. Sensor 1 should be the up stream sensor though, the one in front of the cat.
 
PitbullRescuer said:
You sure it was a coil and not the O2 sensor? Bank 1, Sensor 1 doesn't make sense for it being an O2 sensor. I could be wrong, I'm no expert but sound right to me. Sensor 1 should be the up stream sensor though, the one in front of the cat.
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Yeah, a couple people at Autozone said it's an O2. I'm pretty sure it's the one in front of the cat too, just want to make sure before I do all the work to the wrong sensor. Anyone else confirm?
 
It is the one in front of the cat, just soak it in some pb blaster, let it sit. Take it off and replace it, plug it in and clear the code! Cant mistake it for the wrong one, it's right off the engine on the exhaust. The downstream sensor is on the other side of your cat.
 
daMicr0wav3 said:
Yeah, a couple people at Autozone said it's an O2. I'm pretty sure it's the one in front of the cat too, just want to make sure before I do all the work to the wrong sensor. Anyone else confirm?
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On '98 and earlier, and '99 and '00 49-state rigs, both sensors are definitely O2 sensors. Sensor 1 is always the pre-cat sensor, somewhere between the cat and the engine. Sensor 2 is post-cat, between the cat and the muffler. All 3G's have only two exhaust sensors; there is no Bank 2 exhaust.

For less than $109 you could have gotten a Denso O2 sensor on Amazon (same as factory). Bosch sensors frequently cause problems.
 
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I agree with The Durk.. I tried the Bosch the first time & it didn't last 6 mnths... I, on the other hand, also have a question about the O2's.. For some reason, every one I've put on, I had to take a knife and shave the "raised lips" on the O2 plug itself to get it to plug into factory plug... They're always on the wrong side of the plug... Anybody have any idea what that's about..?? Just curious.. BTW, I replace them with Denso so you would think they would plug right in..
 
daMicr0wav3 said:
Thanks guys -all great info. The bolts aren't bad, like mentioned above it's been in Florida so it shouldn't be a problem getting off. And yes, it is a Bosch, was $109 but my friend had an employee discount for 25% off, OEM fit, so I couldn't pass it up.

My original question still stands though, which O2 sensor is bank 1, sensor 1 and where is it located exactly, so I know I'm changing out the right one!! :) And I thought there were 4 O2 sensors??
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I answered your question in post 3? I guess maybe i didn't give enough detail?
 
Get under there, find the cat and trace towards the motor, you will see it and cant mistake it for something else. Good luck with the bosch, i havent heard good things. I have a forum for my dodge truck and bosch has a bad rep there too. Sadly, i work for their parent company.
 
HCurphy said:
I answered your question in post 3? I guess maybe i didn't give enough detail?
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AAH, I see it now, was reading the e-mail responses and not on the forum. Props to you first of all :)

Well I have the receipt, maybe I can return it and get a Denso.

Typing it in on Amazon and to save me some looking up, does anyone know which one it would be for the Bank 1, Sensor 1 on here
 
daMicr0wav3 said:
AAH, I see it now, was reading the e-mail responses and not on the forum. Props to you first of all :)

Well I have the receipt, maybe I can return it and get a Denso.

Typing it in on Amazon and to save me some looking up, does anyone know which one it would be for the Bank 1, Sensor 1 on here
Click to expand...

Look here:DENSO Aftermarket Online Catalog | Vehicle Parts Search



Looks like a 234-4161 if you have the V6.

http://www.amazon.com/Denso-234-4161-Oxygen-Sensor-Ratio/dp/B000C5SGAO/ref=au_pf_pfg_s?ie=UTF8&Model=4Runner%7C1005&n=15684181&s=automotive&Make=Toyota%7C76&Year=1998%7C1998&vehicleType=automotive&newCar=1&carId=004
 
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Alright! Was able to return the unused Bosch and they gave me full price back, so I actually MADE money on it, then I just ordered the Denso from Amazon for $58.xx. Sweet!!
 
Almost forgot to give an update and thank you guys for your help.

Replaced the 02 sensor, the old one wasn't very hard to get out, not alot of rust, however, trying to get the CLIP undone is always a pain for me, and when I couldn't see it, since it was sitting on top of the transmission, I had to do it basically with my eyes closed.....fun. Anyway, after alot of pouting I finally got it unclipped, had the bung cleaned up and the new o2 put on in no time while the battery was disconnected, started it up, and bam, no more engine light....ran great.........until.....

...Ran it about 30 miles that day, then on the way home the check engine light comes back ON!!!??!!! wtf

...Ran it a couple days to see if it would go off like it sometimes would, never did. So reset the battery yesterday, light went back off....so we'll see how it likes the o2....

Will let you know, thanks guys.
 
pull the code next time it comes back. I'm betting p0420 or whatever the code is for the rear sensor.

Sometimes O2's need to be changed in pairs to avoid this situation. If the back one was a little out of spec AND the front one was, too. Then the back one seems fine, then you put a brand new one in front and suddenly the rear one is reading far enough out of spec to throw a code, in comparison to the front that is.
 
HCurphy said:
I answered your question in post 3? I guess maybe i didn't give enough detail?
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I can't seem to find that answer ...I have the same problem - (V8) I now know its the upstream sensor, but driver or passenger side? I may be old, but I didn't see an answer! Help a fella out, please!
 
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