2002 OBW Front Oxygen Sensor

[SubaruMN]

Originally Posted by Peaty

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-sen...64.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 Auto Parts, Car Parts and Auto Accessories at Discount Prices | DriveWire.com I used Bosch but Denso is also and OEM brand.

The link is broken! Any chance we could get a repost?

Also, how long can you drive around with this broken? I heard the downstream O2 sensor is more important, but I can't imagine this is good for the car. Thanks.

[Peaty]

rats I can't edit my post try this link:

http://www.scoobymods.com/showthread...64.html?t=5464

Actually, it's the front one (up stream) that is the important sensor. If that's malfunctioning it can mess things up as the car's ECU uses information from it to regulate help the air / fuel mixture. The downstream oxygen sensor (the one after the cat) doesn't do anything but turn on the CEL if it sees an issue with the cat. It's not a bad idea to change the front one after 60 -80K even if you don't have a CEL because it can help improve your MPG's.

[SubaruMN]

Originally Posted by Peaty

rats I can't edit my post try this link:

http://www.scoobymods.com/showthread...64.html?t=5464

Actually, it's the front one (up stream) that is the important sensor. If that's malfunctioning it can mess things up as the car's ECU uses information from it to regulate help the air / fuel mixture. The downstream oxygen sensor (the one after the cat) doesn't do anything but turn on the CEL if it sees an issue with the cat. It's not a bad idea to change the front one after 60 -80K even if you don't have a CEL because it can help improve your MPG's.

Ugh, ours has been on for a few months. Hope nothing else has broken in the meantime. Just been too busy to fix it.

[Peaty]

have you pulled a code? Are you sure it's the front one? AutoZone will pull the code for free.

[SubaruMN]

Yeah I'm throwing P0130. The reader I borrowed even said "O2 Circuit, Bank 1, Sensor 1." I Googled it and the front O2 sensor seems to be to blame.

[Peaty]

That would be the one then, you really should get to it ASAP.

[SubaruMN]

Project completed tonight. Honestly thought I wouldn't be able to do it, but the sensor finally broke free. The hardest part of the whole ordeal is getting a good angle on it with the wrench. I think the special socket is essential and soaking it overnight in PB Blaster was the key for me. (Granted I have a lot of rust from salt exposure.) Those of you who did it without a special socket (slotted 22mm one) are gods among mere mortals. There must have been some magic involved. I didn't remove anything. Was able to get at everything without taking the wheel off or the air intake.

I didn't use the above method showing top access. I was underneath the car, feet towards the rear with the socket in place and wrench pointed to the passenger side. Pulled down with all my might with both arms (had to re-jack the car and put the jack stands higher). Couldn't get it to break free last night, soaked it overnight and went at it again the following night. Almost quit when I couldn't get it to work with the breaker bar, then used my lowly socket wrench and it worked. I think having the right tool makes or breaks this job. There is a VERY limited work space. I seriously thought I got some tools stuck in place multiple times. There is a LOT of up and down for this job. I can't count the number of times I got under the car and back up. Having a second person would be really helpful.

I used the Bosch oxygen sensor. It is OEM. Got it for $62 in person at Advance Auto. Used their oxygen sensor removal tool. $30 deposit which you get back.

Thanks for everyone's help. If others tackling this have questions, please bump the thread and I'll do my best to help.

For those tackling this job, I found this video really helpful:

Oxygen Sensor Change - YouTube

Oxygen Sensor Change - YouTube

[They-Call-Me-Dirt]

Originally Posted by paweliania

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

I replaced Bank 1 & Bank 2 at the same time. They're literally the same sensor, and if you replace only one, chances are down the road the second will light up on the idiot light..
I removed and reinstalled everything no problem without any special tools or anything. I ran the car for a bit to heat up the metal so it'll expand. Jacked it up, sprayed on "Penetrating Oil / Liquid Wrench," cleaned the surrounding area with a rag (it is flammable - SO BE CAREFUL! ENGINE OFF!!). Let it all soak, then unplugged them from the exhaust manifolds (Airbox removed does make for less hassle). Ran the wiring from the sensor through the closed end of a 22mm wrench, and tapped it with a rubber mallet until it came loose. Reinstall is basically the opposite (get correct Bank - there are 4 all together). Make sure you are careful doing all of this! I did mine on my back, on the floor. You definitely don't want over 3k lbs. to fall on you. There's other quick fixes too with Subarus like taking a hacksaw to the old sensor, but I DO NOT recommend that. Hope it helped even though it's a late reply!

[They-Call-Me-Dirt]

oh, after it's done, hook up an OBD II scanner and clear the code before it comes up again. You'll want to disconnect the battery since it's electrical and the light goes off for awhile..

[VIoutback]

Changed the O2 sensor yesterday on my 04 obw 2.5 with a minimal amount of cursing. Definitely tried a few different angles and tool configurations before the old one came loose. Thanks to everyone for the tips.