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'02 OBW 2.5 AT
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46 Posts
Discussion Starter #1
This is how I had everything set up for my '02 Outback Wagon with automatic transmission (AT) for replacement of the front oxygen sensor. I saw everyone talking about it but no pictures, hopefully this helps someone else out.

Tools used:

10mm socket
3/8" drive socket wrench
(Used to take the air intake, and air box off)

22mm Oxygen Sensor removal tool
1/2" drive socket wrench
6" extension
1/2" Flex Socket
Front Oxygen Sensor

Lots of WD-40... Dripping... Prior to removal

Step 1: Remove the air intake
Step 2: Assemble tools as in the picture (I did it from under the car)
Step 3: Loosen once, reset the tool and loosen again if necessary

Reverse procedure to replace, again I had to tighten once, and reset the tools to tighten the oxygen sensor completely. I hope this helps someone, or anyone.
 

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'02 OBW 2.5 AT
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46 Posts
Discussion Starter #2
I forgot to mention, under the car to assemble the four tools together and then from above to loosen (or tighten) the oxygen sensor. Back under and then repeat.
 

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2001 Subaru Outback
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25 Posts
Do you know if it is possible to remove the oxygen sensor without the special socket? Just by using a regular 22mm socket?
 

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2005 Outback H6 3.0 LL Bean
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1,203 Posts
A 22mm wrench will do it.

I just used a carefully-set pair of Vice-Grips. It isn't that fragile, but you don't want to crush it.
 

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'00OBW, '96&'94 Legacy - all rusted RIP, current: 2016 Focus MT
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4,804 Posts
Hm nice writeup and approach. Didn't think of using this method, it looks good. It is tight clearance in that area down there on the 2nd gen 4cyl.
 

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37 Posts
I have a 2005 OBW and man I honestly can't see how this would work in it... maybe that area really is that different (doubt it, idk) but really.... the o2 sensor is RIGHT THERE on the bottom of the car, but there's a (what I presume to be the exhaust) housing just in the way, just barely. I have it soaking in lube and hope to take that housing off tomorrow and see if I can get clearance for the o2. If that housing comes off, on the 2005 the sensor will be stupid easy to replace....
 

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'00OBW, '96&'94 Legacy - all rusted RIP, current: 2016 Focus MT
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4,804 Posts
Running the engine for a minute or so just before trying to break loose the old sensor I find very helpful. Although it does of course make the exhaust hot so have to careful about that.
 

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37 Posts
Man I am at my wits end (which means I am just going to take the car and pay someone to do this)... I can NOT see how to get a wrench in there and get ANY torque on this O2 sensor. I even got the special 22mm socket. Can get it physically connected on the O2 sensor... then.. nothing. I have about 1cm worth of leverage on the wrench at that point.

I am SO frustrated. stupid o2 sensor.
 

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Had a nice 50 degree day yesterday, decided it was time to tackle the pre-cat O2 sensor. Armed only with a 22mm wrench and not being able to see the **** sensor I felt beaten before I started. Luckily I soaked the "area" with PB Blaster a couple days in advance. I really couldn't see if I was hitting the sensor but I knew enough would ricochet onto it if I shot enough in there.

So, onto the sensor. I removed most of the air box piping on top of the motor. It gained me pretty good access where the sensor sat on top of the cat converter. However I still couldn't see it! After the BS was moved I grabbed the wrench and sure enough, it grabbed! I'm thinking, this is great, it'll be out in no time. Well, I reach down and use all my might and the wrench laughs at me. There was no way I could reach down that far and get any leverage.

To make a long story shortER, all you need to do is remove the right front wheel and the cat converter sits right there. It's a bit of a stretch but you can reach BOTH O2 sensors. I lucked out (I hope cuz of the PB Blaster) in that once I broke the pre-cat loose I could spin it by hand.
 

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To make a long story shortER, all you need to do is remove the right front wheel and the cat converter sits right there. It's a bit of a stretch but you can reach BOTH O2 sensors. I lucked out (I hope cuz of the PB Blaster) in that once I broke the pre-cat loose I could spin it by hand.
Wheel off, now that is something I didn't think of. I might give that another go.
 

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2005 LegGT Wagon 5EAT
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16 Posts
Anyone would have the pat number for this O2 sensor (2003,H4,Auto)?
 

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97 Lego, 00 OB, 66 Bellanca, Honda, Toyota
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31 Posts
Autozone had this really cool tool that worked perfectly without dropping the exhaust. It's and
OEM angled, swiveling line type wrench. Drove car up on home made wooden ramps, about 6 inches.

Didn't have to remove anything

Job took about 45 minutes with son helping.
 

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I simply cannot abide useless people.
2006 2.5i and 2002 3.0 wagons.
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12,304 Posts
*Whew.*

Just replaced the front O2 sensor on Kaylee. That was not exactly fun. Would have been better with some tools I did not have. I had the cheapest O2 removal tool from Advance Auto, a 3/8 half broken swivel head socket wrench, and a lot of bruised knuckles.

In the end, I actually had to ask my wife to thread the new sensor into the exhaust, as I could not get my hand to fit in the gap and to turn. She lovingly obliged. But the CEL is now off and Cruise Control works again. I'm happy that the job only cost me $150 and not $300.
 

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2000 Subaru Outback
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21 Posts
My CEL went on last night and what do you know, Front o2 sensor set it off! Did you guys buy OEM sensors? I might try the front wheel off technique.
 

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I simply cannot abide useless people.
2006 2.5i and 2002 3.0 wagons.
Joined
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12,304 Posts
I used a Subaru sensor. Car has been fine since. OEM was either Bosch or Denso...but since I could not remember, nor was it stamped on the factory sensor I ordered a new Subaru part. About $130 I think.
 

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Lord of ScoobyMods, ,
19' Impreza Sport 5 dr / 01' Forester S / 13' OB CVT / 10' Legacy 3.6R / 99 Mita MX-5
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1,213 Posts
I just did both front and rear in my kids 2001 Outback. I used the crows foot style. I didn't have to do anything special other than get the car on ramps. I'm not sure if it's possible to do it w/ a regular wrench it's pretty tight. I can say there isn't enough room to use the type of O2 tool that looks like a spark plug socket (with a slot for the wire)

I have pics here of the tool with some info:

http://www.scoobymods.com/oxygen-sensor-removal-02-sensor-t5464.html?t=5464

I can say it's a lot easier with the proper tools. Places like AutoZone will lend them to you for free so it's not a big deal to get them. You just need to leave a deposit that you will get back when you return the tools.

It helped me to attach the crows foot to a 3/8" breaker bar (from the bottom as in my pics in the link) to give max clearance to work.

One tip that I can give that helped me a lot. Dealing with the wire on the end is a bugger. Both loosening and tightening the sensor. When removing and installing, I had an assistant (my teenage son in this case) turn the end of the harness to twist up the wire with some torque. That helped get it off easier once it was loose and after I had the threads started when installing it. Because of the funky angle I still had to snug it with my fingers but it went a lot smoother with him twisting the end the right direction.

Do yourself a favor and do not get a universal sensor, the one you need to cut the harness off and re attach. Those work but are a PITA to deal with trust me. I got mine from www.drivewire.com I used Bosch but Denso is also and OEM brand.
 

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Lord of ScoobyMods, ,
19' Impreza Sport 5 dr / 01' Forester S / 13' OB CVT / 10' Legacy 3.6R / 99 Mita MX-5
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1,213 Posts
Exact same one I just put in our OB, same price too. I wonder if they are really the same store.

DriveWire - Sensor

In any case it works just fine, you should be good to go.
 

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2002 OBW, AT, 2.5
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2 Posts
Taking the passenger side wheel off gave me enough access, but just barely. I had a friend leaning over the top as well to be my eyes, which made a huge difference. We borrowed the specialty O2 sensor wrench from the parts store, but ended up having more luck with a conglomeration of open ends and adjustables as well as one of those grippy jar-opener pads, which I will keep in my toolbox from now on.
 
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