Help! Just Got A Diagnostic!

[scuba_suit]

so the 'check engine light' comes on, and yes "oh crap, what now" thought crossed my mind. took my subaru (2003 outback station wagon) to get a diagnostic at the auto store. they ran it through, and got this read out:

 

PO3002

HO2S

bank 1, sensor 1

 

the associate at the auto store said that it looks like it could be emissions, took my sub to a mechanic, he checked it over and told me that it was the oxygen sensor (i believe that he told me it was the 'downstream' sensor) and that the piece would be $180 (he told me that if it was the 'upstream' sensor, that it would set me back $500, WHUT!?), i want to know is (because of money issues) what can happen if it don't get this repaired right away? i'm strapped for money (yay high gas prices!) and i don't want to see this become worse soon but want to know what could happen, case in point: the family wants to take a trip, an 800 mile trip (1600 miles roundtrip), i'm nervous driving around as it is and my nervousness goes into overdrie when i think about taking the wagon on a long trip like that, i don't want to get stuck in the middle of nowhere, can someone tell me if what the mechanic said was true about the oxygen sensor?

[idosubaru]

that should be the Oxygen sensor closest to the engine.

 

$500 is off the charts and i think he probably misdiagnosed to come up with that price. subarupartsforyou.com shows 2003 Outback sensors ranging from $140-$160 (depending on 2.5 liter or 3.0 liter H6 engine), not sure if this link will work for you:

http://www.subarupartsforyou.com/cp_partlistbymod.php?model=Outback&subcat=Engine+Parts%2C+Sensor+O2&year=2003

 

i've never done a 2003 but Oxygen sensors in general are really easy....particularly on new cars like yours. it doesn't require any work to replace them. it only takes one 22 (or 24?)mm wrench to get them out. i've never had to remove anything to replace an oxygen sensor, just unscrew it and thread the new one in. it's just one step above removing your gas cap and replacing it. not much different except you need a wrench and to disconnect the wiring harness (clip on, clip off).

 

$500 sounds like he means to replace the converter - do not do that. subaru converters do not fail...without something else major being wrong which you haven't indicated.

 

a new front oxygen sensor might save you gas mileage though so it would be nice to get. but it won't cause any running issues at all or leave you stranded. again...not sure about the 2003 but on most subaru's you can disconnect the Oxygen sensor entirely and the car still runs fine. probably get bad mileage, but my point is that you won't get stranded by it, it's not a big deal.

[McDave]

Yes, Sensor 1 is always the one ahead of the cat, and $500 is too much for just a sensor, or even two.

 

BTW... P03002 is not a valid trouble code. Just for grins check all your fuses, particularly those in the engine compartment fuse box (assuming your car has one). The sensor is the heated type and may have blown a fuse.

 

Then take it to another shop or dealer that can properly diagnose the problem. Not all O2 trouble codes mean the sensor itself is bad, and at this point we're not even sure it's an O2 code.

[scuba_suit]

thanks so much! i knew i could come to this site for the best advice, i love my subaru to death (i was a vw fanatic, WAS...), i did check the net to see how much the piece would come out to, i saw sensors for my 2003 (2.5L 4 cyl.) for about $35, i'm already taking it to another shop (i checked on cartalk.com to see what other shops around me had good reviews, then again i take those reviews with a grain of salt)...

 

grossgary, where is the sensor located? could i do this myself?

 

mcdave, you mean the fusebox under the hood right by the engine (it has one) not the one inside the car under the steering wheel, right? what fuse would i be looking for? holy moly if it's just a blown fuse, it would be a miracle of miracles (and a money saver)

[idosubaru]

how many miles on the vehicle? if yo'ure getting close to 100k, then it's not surprising to be replacing an O2 sensor. they vary wildly of course but they are *very roughly* 100,000 mile replacement items.

 

yes - do this yourself. the front O2's on all Subaru's i've worked on are very easy. a little tight, yes but all you need is a 22 (or 24, i'm forgetting) open ended box wrench. that's it. it's tight but that's all you need. no need to jack the car up, remove anything else, etc.

 

some you can get from under the car, some you'll need to get from inside the engine bay.

 

just follow the exhaust back from the engine, the first item you see threaded into the exhaust with a wire on it - is the O2 sensor. it's the only thing threaded into the exhaust except the rear sensor, so it's REALLY easy to find. it's just a foot or so behind the oil pan.

 

keep in mind there are two types of sensors to buy - one will have the stock plug on it that plugs right into the wire on your car. the other will have loose wires and you need to cut and splice the connector off your old plug onto the new one. the loose wire style O2's are the cheapest. it's not hard, but if you don't want to do any wiring work you'll want to make sure you buy the one with the OEM style connector already on it.

 

there are some items that are best to stick with Subaru on depending on the engine. some people would suggest your engine should have a Subaru O2 sensor. i'm not sold either way on that item yet though, just letting you know.

[McDave]

mcdave, you mean the fusebox under the hood right by the engine (it has one) not the one inside the car under the steering wheel, right? what fuse would i be looking for? holy moly if it's just a blown fuse, it would be a miracle of miracles (and a money saver)

Yes. The fuse may or may not be labeled HO2 and there will be more than one O2 fuse. A test light tool is the best thing for checking fuses as you don't need to remove them to check them. I always test all fuses as I've found weird things in the past on some makes, like the ecu wired to the same fuse the cigarette lighter uses on a Chevy truck.

 

If you end up replacing the O2 sensor, I would get one from the dealer. That $35 one is likely a cheap universal.

 

It's good that you're having another shop diagnose it. I would let them go ahead and change the O2 sensor if that's what's needed. Some cars have a front sensor on both banks and you won't know which is which unless you can get them to tell you. Plus if that doesn't fix it (remember what I said earlier about O2 codes), then they will need to diagnose further.

 

Gary's right though, if you have 100k or more you're due for front sensor(s) anyway. The wrench size is 22mm.

[scuba_suit]

thanks for the knowledge grossgary, yeah the car has about 85,000 on it (it needs an oil change too), i did see sensors with the oem adapters and ones with the cut wires that you would need to splice, knowing me, i'd pick the ones that i could splice (eventhough i never done it before, but it shouldn't be that hard, just match the color wire right?), but then again, knowing me maybe the best (and surest) way to get this done is to go with ones with the adapters, i'll go out and check my car in a few, the only thing i don't have is the wrench.... i wonder if i could just rent it, like home depot rents tools?

[McDave]

 

keep in mind there are two types of sensors to buy - one will have the stock plug on it that plugs right into the wire on your car. the other will have loose wires and you need to cut and splice the connector off your old plug onto the new one. the loose wire style O2's are the cheapest. it's not hard, but if you don't want to do any wiring work you'll want to make sure you buy the one with the OEM style connector already on it.

 

there are some items that are best to stick with Subaru on depending on the engine. some people would suggest your engine should have a Subaru O2 sensor. i'm not sold either way on that item yet though, just letting you know.

I have an aftermarket Bosch on my ea82, but it's just a single wire O2 sensor. It works fine but the wire is about a foot longer than oem. The HO2 sensors are a much more specialized fit so I wouldn't recommend a more universal type replacement, particularly with a lot of the crap that's in the aftermarket these days. Even the "Direct Fit - OEM Type" sensors aren't Exact fit. ymmv

 

Edit: Just to clarify: I prefer dealer parts when it comes to emissions components... hands down.

[idosubaru]

i would get the direct fit OEM style. you'll want this to last another 100,000 miles or few years. having never done it before you probably don't have good electrical working tools...crimping tools, shrink tube, etc. and you want to make sure you get a good connection that won't get dirty or corrode over time. better off just buying the direct fit style for a few more dollars. and...the newer style ones have 3 or 4 (two different styles) wires on them.

 

maybe you could borrow the wrench from a friend or something? i recall those large wrenches are rather expensive. some places...autozone or whatever do have loaner tool programs. just ask if they have a wrench the size you need.

 

keep in mind too that you'll need an open ended wrench an "O2 Sensor" tool won't work on a subaru, at least on the ones i've done.

[johnceggleston]

 

keep in mind too that you'll need an open ended wrench an "O2 Sensor" tool won't work on a subaru, at least on the ones i've done.

IIRC, the 22mm is the same as 7/8 inch. this may be easier to find. i think i changed mine with out a 22mm, so i would have uesd my 7/8 - 3/4 open wrench .

[Gnuman]

Because the fit is so tight, I generally use a 7/8 box wrench (unplug the wire and you can slide the box wrench down it and over the sensor). I also recomend OEM, and by that I mean genuine Subaru for this sensor. O2 sensors vasry widely in thier manufacture, and I have seen the "universal" ones simply not work on a Subaru, or be so marginal that they fail after a few weeks at best. There is only one bank of O2 sensors, and sensor 1 is the one threaded into the front of the cat, or perhaps on the pipe between that and the engine. Fairly easy to get to. Should be on the passenger side behind the engine in the engine bay.

[scuba_suit]

yeah, i think i'll go with one that's direct fit and not cut, okay i went out to check my car, i popped the hood and went lookin for the sensor, question: is the sensor located on the left close to the bottom but above the exhaust, car facing me (passenger side of the car)? i'm a newbie to automotive engine maintenance so i want to be lookin at the right thing before i go diving in, as for the tool loaners at the auto store, i'm going to call up autozone/advance auto parts to see if they do it

 

in regards to the engine fusebox, which fuse am i lookin for? i see a bunch of relays and sbf fuses, does anyone know how many amps the fuse is for it? i am PRAYING it's the fuse and not the sensor (the car runs like a dream)....

[johnceggleston]

changing this thing out is not hard, but if you haveno experience, you might consider buying the subaru part, online, and paying a local garage to put it in. it should onlt cost about 40 or 50$ to have it put in.

[scuba_suit]

i 'll check for the subaru part and see how much that piece is going for, i want to do this myself, and thanx gnuman for givin me detail on where the piece should be and yes that's what i was lookin at before, i'll call the nearest subaru dealer to see if they have one in stock, i just don't want to take it to someone, the last garage was going to charge $90 for labor, i ain't rich....

[four-fleet-feet]

Yes, Auto Zone rents tools. They also have the reader for your car and will read it for free. Have it done again and make sure they give you the printout sheet (looks like a register receipt with all the pulled codes and possible solutions).

 

O2 sensors don't go bad often, so I'm glad you've decided to get a Subaru one for your car. Why do this twice if you don't have to? Unless you still have your Subie in 100k when the next one gets popped in, that is. If there's one thing I've learned on this forum, it's when to get OEM parts and when it isn't necessary. This is one of the times OEM is just worth it (the main others being plug wires, knock sensors, and PCV valves).

 

Don't think you have to go to the dealer to get this installed, though. If you have access to a trusted mechanic, you can always ask questions and do it yourself. The feeling of 'I did that!' is worth any greasy hands or bloody knuckles, trust me.

 

(Just call me 'She who told the dealer to go stuff their $175. LABOR charge to put in the Subaru knock sensor I already had!' Sheesh - that WAS a stealership! Ten minutes of my time and I was off to lunch!)

[idosubaru]

i 'll check for the subaru part and see how much that piece is going for,

look it up online at subarugenuineparts.com or subarupartsforyou.com. or just PM/email Subiegal (she's a member of this forum and works at subarugenuineparts.com). the online places sell for very reasonable prices where your local place will be more - actually the subarupartsforyou.com place will show you what the local place charges - "retail" next to their price.

 

if you don't want to order it online, what you can also do is print out the prices and stop by your local dealer and ask if they'll at least come close to the online prices. my local dealer does this for me. i still order most of the time since i'm pressed and like it laying on the doorstep when i get home rather than going to pick it up.

 

O2 sensor is easier to see from the passengers side. from above look either around the air intake hose or from underneath in front of the passengers side wheel. - it's below the motor and sticking up out of the exhaust pipe (just after the two exhaust sides come together).

 

good luck!

[scuba_suit]

so far i've been looking for the sensor, i've been looking to see if i can find a subaru piece and i find that vendors here have bosch and denso, if i had to pick, which one? i also called about tools, they don't rent out wrenches, being the ignoramus that i automechanically am, could i just use an adjustable wrench from home depot (and please give me a solid answer on this one, a "maybe" and i'll go off and do it), all of everyone's advice and suggestions have been the best....

[Gnuman]

Just buy the single 7/8 combination wrench (box on one side, and open end on the other) from Home Depot, and use that. you will need quite a bit of force to loosten it if it is rusted in place at all, and an adjustable wrench will flex under those conditions, causing you to round off the corners of the sensor and make it even harder to remove. I would order the Genuine Subaru part as it is sure to fit and mate up easily with your harness. I would get it from Jason at 1stsubaruparts (call, don't use the site. 866-528-5282, ask for Jason in parts) or you can use the places that were mentioned earlier in this thread. It may take a few days to get to you, but you will know the part is the right one, and you will not have to splice the wires, making it very easy to install. This will also give you time to go get that wrench.

[scuba_suit]

gnuman, if no one's told you, you are the wiz, well, here's the update: i went to the subaru dealer and got the sensor (they looked up the piece with my VIN) and got the wrench from lowe's which is by my house, so i'm lettin the engine cool down and i'ma get to it in a few and i'll let all know the outcome....

[scuba_suit]

....and it's RUSTED tight. am i spinnin it the right way? left or right? i'm dizzy and greasy, i don't know which way is up, i'm in there pushing the wrench hard to the right to make the sensor spin left (it's upside down, where the nut is on the bottom), everytime i'm pushin and feel like it's moving, i take out the wrench but it feels like i'm rounding the edges, i gotta stop for the night and try tomorrow, is there any advice out there to try to get it off? what would be good to try to budge it? there's not a lot of room in that area, i'm like "this" close to grabbin some wd-40 but i don't want to blow myself up.... here's a question that i shoulda asked: how long should i wait for the engine to cool to work on it? i mean it seems cool to me, i can work on it without burning myself but i was driving it about an hour ago, should i wait til tomorrow morning?

[Gnuman]

With the wrench on the nut, and the arm toward the back of the car, you need to pull it towards you, so the sensor makes a counter-clockwise motion if looking at it from the top. Yeah, I did say it might be tight. . . That is why I recomended the box wrench, you can pull harder without damaging the turning surfaces.

[scuba_suit]

well it's nighttime and i'm exhausted, i'm gonna try tomorrow first thing when it's real cool out and the metal in the car has had a chance to contract (hopefully making it a little easier to get it off, i'll give the details tomorrow....

[Olnick]

i'm gonna try tomorrow first thing when it's real cool out and the metal in the car has had a chance to contract

 

Hmmm, just the opposite from what I remember reading awhile back! You might want to try a search to confirm.

 

First, give the thread area a few treatments with a good quality penetrating oil or spray (NOT WD-40!) over a period of a day or so.

 

Second, warm the engine up a bit before attempting to loosen it.

 

Worked quite well for me.

 

Good luck.

[scuba_suit]

thanks olnick, it's 7:36am and i just came in from trying to loosen it, the thing will not budge, what kind of penetrating spray would you recommend? can i walk into an auto parts store and get one off the shelf? i think that's what i need for it to move, i am tellin you folks, i don't want to give up on this (my wife calls it "hardheaded'), how long do you guys think it will take for the 'check engine' light to go off once the piece is in? like a day or two?

[Olnick]

PB Blaster and Kroil sprays are well thought of. I like good old fashioned Liquid Wrench too. Any auto parts store will have.

 

CEL should go off after a few driving cycles.

 

Use the search function to look up "oxygen sensor" and you'll find a lot of useful info.