Subaru Legacy/Outback "Check Engine" Light Problems

dswissdswiss Member Posts: 11
If you are reading this message, you probably know what this is all about. You have gone through multiple 'check engine' light episodes, have replaced multiple oxygen sensors, and are on your third or fourth catalytic converter. I had a 2004 Legacy wagon with 80,000 mi, and my friend (still) has a 2004 Outback. We both have had the same experiences, so these problems are certainly not isolated incidences. In fact, my mechanic told me that has seen all kinds of creative means to disable the 'check engine' light. However, if you live in New York State and need to pass the annual emission test, you will have no choice but to fix the problem. In my case, I also had a transmission replaced, and had a cruise control problem that was unfixable (Subaru started an investigation, but were unable to find the causes of the problem). To retain my sanity, I finally traded the car in on a BMW and took a financial hit.
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Comments

  • ateixeiraateixeira Member Posts: 72,587
    What were the codes?

    O2 sensors won't fix it. Spark plugs, spark plug wires, and maybe an ignition coil might. The coil is only $80 and there's only one for all 4 cylinders.

    Tell your friend to try that. It's worked for other Edmunds.com members.

    Honestly, you just need to find a better mechanic.
  • turbotatoturbotato Member Posts: 2
    Hi,

    I'm working on an '01 Legacy (140K miles) for a friend. The check engine light is lit, but the code reads "N/A?" I can clear the code, but it comes back after a few minutes. The car runs fine cold, but is a little sluggish just off-idle when warm...once you get it rolling at speed, it feels fine. I've checked the plugs, air cleaner, cleaned the throttle body, battery connects and given it a general look over...I see nothing obvious. With this kind of mileage, he doesn't want to invest a ton in it. Anyone ever run into this error? Thanks in advance for your help...MT :sick:
  • ateixeiraateixeira Member Posts: 72,587
    No, and I'm really surprised there would even be such a code.

    I wonder if paisan has seen it before, paging paisan...
  • xwesxxwesx Fairbanks, AlaskaMember Posts: 16,130
    Makes me wonder if it is simply a problem with the scanner reading the code properly.
    2018 Subaru Crosstrek, 2014 Audi Q7 TDI, 2013 Subaru Forester, 1969 Chevrolet C20, 1969 Ford Econoline 100, 1976 Ford F250
  • ateixeiraateixeira Member Posts: 72,587
    I have an Actron one, pretty simple, but if anyone's in the DC/MD/NoVA area and needs one they're welcome to come by.
  • xwesxxwesx Fairbanks, AlaskaMember Posts: 16,130
    Well, what I am wondering is whether the scanner has some hardware limitations that make it not 100% compatible with the Subaru OBDII system. It may be an OBDII scanner, but that does not mean it has all the code compatibility.
    2018 Subaru Crosstrek, 2014 Audi Q7 TDI, 2013 Subaru Forester, 1969 Chevrolet C20, 1969 Ford Econoline 100, 1976 Ford F250
  • paisanpaisan Member Posts: 21,181
    Yup Wes beat me to it, it's the scanner not having all the Subaru OBDII codes. Often times this happens with cheaper OBDII scanners.

    -mike
  • turbotatoturbotato Member Posts: 2
    Thanks for the feedback guys. The scanner is a fairly cheap one (~$100), but I've never run into a car it couldn't scan yet...there's always a first. I get so many requests to scan cars from folks at work that I always carry it in my backpack. Wierd how it will clear the code....but it comes back once the car has been driven about 5-10 miles. Another garage told the owner that the code comes back for a bad knock sensor. I haven't looked at it again, but the owner says that the knock sensor is tough to get at...Anyone been there done that? Thanks again for the help...MT
  • xwesxxwesx Fairbanks, AlaskaMember Posts: 16,130
    I doubt it would have issues with all codes generated by the car's computer, but some of them are manufacturer-specific. I would not think the knock sensor to be one of those. In fact, it seems to me that a knock sensor problem would cause more of an issue while the car is cold than warm! Maybe I am just not thinking it through well enough though. How about airflow sensor? Input is bypassed from that circuit until the operating cycle reaches a preset temperature.

    The knock sensor is mounted on top of the engine, just slightly on the right side (looking at the car from the front), and near the back of the block. It is somewhat underneath the intake manifold. It is not overly difficult to access, but it is a tight space - especially plugging it in!

    Keep us posted with what you discover, please!
    2018 Subaru Crosstrek, 2014 Audi Q7 TDI, 2013 Subaru Forester, 1969 Chevrolet C20, 1969 Ford Econoline 100, 1976 Ford F250
  • deeandeean Member Posts: 1
    Just changed this sensor ($60) on my mother's 2001 Legacy. Very easy to do. Haynes manual has good a description. Make sure to note the orientation of it. I put a long socket extension between the two throttle cables to get to the bolt directly below on the engine block. You'll need a new cable tie unless you figure out how to unlock it. Her car runs better now.
  • sapphirebluesapphireblue Member Posts: 29
    Hi all. I have a engine light question re: my 2005 Subaru Outback 2.5i wagon. :confuse:

    After driving from MD to NC and back this past weekend (with no problems) ... today I was driving around and, mid-way thru errands, the yellow "Check Engine" light turned on, and the green "Cruise Control" light started to blink on and off. I tried to "turn off" the CC using the handle by the steering wheel (even tho' I wasn't using it), but no luck. And stopping and restarting the car still gives me the error.

    Any ideas on diagnosis and fix, or should I just take it into my local mechanic? (I'm not super car-fix handy myself.)

    Thanks,
    sapphireblue
  • paisanpaisan Member Posts: 21,181
    The cruise comes on like that to alert you to the CEL that is going on.

    -mike
  • sapphirebluesapphireblue Member Posts: 29
    Is this something my regular mechanic can diagnose and try to fix? Or do I need to take it to a dealership?

    And if it is an engine problem (e.g., cylinder issue), is that covered under the 3Y/36000 mile warranties (which I am still under)?

    Thanks,
    sb
  • paisanpaisan Member Posts: 21,181
    Anyone with an OBDII scanner can pull the code. If you are under the 3/36k that is a bumper to bumper warranty which means that whatever is causing it should be covered.

    -mike
  • holteholte Member Posts: 4
    I have a brand new 2008 Subaru Outback with 350 miles. On my way to work yesterday my cruise started flashing & the check engine light came on. I called my dealership but they can't get me in until Monday. Has anyone experienced this issue? Thanks
  • paisanpaisan Member Posts: 21,181
    The CEL + Cruise flasshing just means your have a CEL which could be anything out of about 200 different codes. You'll have to wait and see what the code says when hooked up to an OBDII scanner. Could be something as simple as the gas-cap was not tightened all the way on your last fillup.

    -mike
  • holteholte Member Posts: 4
    It was as simple as gas cap not tightened.
    They cleared the code a few weeks ago & since I've tightened the gas cap it hasn't come back.
  • crazycarolcrazycarol Member Posts: 2
    I am repairing a 96 lecacy 2.2 sohc. code is setting rear o2 sensor and cat efficiency problems. replaced both cats and both o2 sensors. ce light returns after 20 miles or so. any help would be nice.
  • dswissdswiss Member Posts: 11
    If you have less than 36k miles on it, bring it to the dealer and they will keep fixing it. If you're out of warranty, you can reset the light by disconnecting the battery and shorting the +/- cable of the car for a few seconds. Then reconnect the battery. However, if the light keeps on coming back, there is a good chance that you have the same problem me and many of my friends had: An emission control system problem. that will kleep reoccuring and costing you lots of $$. Consider selling your car.
  • hydrodudehydrodude Member Posts: 1
    Hello all,

    I need help, I recently purchased a 97 Legacy GT with the 2.5l eng with 195k miles. shortly after I got it the CEL came on. I had the dealership check it out for me and the tech told me it was calling out a #1 cylinder misfire. since then I've changed the spark plugs, wires, and the coil, and the still came back after they reset it the third time. the eng runs great, except for every once in a while when I stop at a light it idles a little rough. I dont know what else to change out. does anyone have any suggestions?
  • paisanpaisan Member Posts: 21,181
    Could be an injector on that cylinder.

    -mike
  • ateixeiraateixeira Member Posts: 72,587
    You already did the 3 things I was going to suggest, so I'm stumped.
  • kurtamaxxxguykurtamaxxxguy Member Posts: 1,798
    I haven't read everything in detail here yet but...

    one subaru owner I knew who had this was told the gas cap, hosing and emission cannisters connected to the fuel filler, were defective. Once those items were serviced, his check engine light problems went away.
  • paisanpaisan Member Posts: 21,181
    Except that those problems would not give you a misfire in a particular cylinder. Those items would effect the evap system or another code related to the emission control area of the car.

    -mike
  • dswissdswiss Member Posts: 11
    What you're saying is that both Subaru dealers I went to have incompetent mechanics. You might have a point! ;)
  • steveknystevekny Member Posts: 6
    Been down your path with a recurring CEL spitting out engine misfire on 3 and 4 with no noticeable loss of performance (98 Outback with 2.5l manual). Problem has been intermittent since about 80K miles (now 134K, with a rebuilt engine at 120K - typical head gasket failure) After checking/replacing wires, plugs, coil I just tried some heavy duty add to the gas injector cleaner. Light went off after about 100 miles, and is still off after 500 miles.
    Advice to anyone with a similar problem....swap the fuel injectors with each other and see if the codes change before replacing all that electrical stuff (unless, of course, it's tune-up time anyway).
    BTW I own Toyotas and Hondas with similar/more mileage, and none have ever turned on the CEL. My POS Subaru does it routinely.
  • horspoorhorspoor Member Posts: 6
    Okay, I bought a 2002 Subaru Impreza Outback Sport at the end of Oct, 2007. It now has 21,000 miles on it. The check engine light came on last night. Took it to the dealer for scheduled oil change today the want $130 just to scan it. Is that a reasonable price, even before they fix anything? Car drives fine. Doesn't get the mileage reported though, and I drive semi grannyish. It sounds like the check engine light is an issue. The dealer did say it was probably a smog/emissions deal that would need to be fixed. So, should I try and get out of this car ASAP?
  • xwesxxwesx Fairbanks, AlaskaMember Posts: 16,130
    No, the $130 sounds like a rip off to me, if all they are doing is reading out the code(s). You could buy your own reader for that and have it on hand for the next time the light illuminates.

    At this point, it is too early to tell if you should look to dump the car. Super low miles for the year, so it could potentially be a good buy for you. Give it some time, and proceed with repairs cautiously. Throwing sensors at the car to solve a tripped code is not a good course of action. ;)
    2018 Subaru Crosstrek, 2014 Audi Q7 TDI, 2013 Subaru Forester, 1969 Chevrolet C20, 1969 Ford Econoline 100, 1976 Ford F250
  • horspoorhorspoor Member Posts: 6
    Thanks, I'll see who else I can get to scan/look at the car. Fun car to drive, park it anywhere and don't worry about getting stuck up at pasture.
  • xwesxxwesx Fairbanks, AlaskaMember Posts: 16,130
    Reading the codes is terribly easy - takes about 30 seconds. You could then take it to a shop with codes in hand. If the shop then wanted to run a full diagnostics on it to pinpoint the problem, it might be warranted if it saves replacing sensors and making several repeat visits to the shop.
    2018 Subaru Crosstrek, 2014 Audi Q7 TDI, 2013 Subaru Forester, 1969 Chevrolet C20, 1969 Ford Econoline 100, 1976 Ford F250
  • paisanpaisan Member Posts: 21,181
    Most shops will charge 1 hr labor to read codes. So it should be closer to $90 to read the code.

    However since your car is a 2002 w/21k miles if it is in fact an emissions problem, it will be covered under the 8/80k emissions warranty.

    My guess is that it may be the gas cap tightening thing, so give it a few days before panicing.

    -mike
  • dswissdswiss Member Posts: 11
    Thats about how long the catalytic converter lasted on my Legacy. By 80,000 mi I was on my third one - all paid by Subaru. After that YOU will have to pay for it, but until then, keep having it fixed at their cost!
    good luck.
  • ateixeiraateixeira Member Posts: 72,587
    I'd buy a scanner.

    I got an Actron model for $99. I've used it a couple of times, plus a couple of times for friends.

    At $130 per use, it's paid for itself more than 5 times already.
  • jumbliesjumblies Member Posts: 2
    Hey, I bought the harbor freight OBDII with CAN for my 1999 Subaru legacy outback wagon which occasionally throws misfire cyl 4 CELs.

    This Code reader works well, cost <$40 USD and helps you figure out right away what the problem is. It also prevents having to stop at autozone to have them read/reset codes.
  • horspoorhorspoor Member Posts: 6
    Okay, I posted here before about my check engine light, and the dealer wanting $130 just to scan it. I unplugged my cell phone charge thing from the cigarette lighter...no more check engine light. Waiting to see if it comes back on.
  • caliberchiccaliberchic Member Posts: 402
    Wow if that's it what a lucky fix!
  • horspoorhorspoor Member Posts: 6
    So far so good, no check engine light. Whew, I hope this is the answer. lol
    Thanks, for all the help on ideas. I am buying a scanner deal. There's a Harbor Freight tools here. Going to go check it out.
  • lostinmarylandlostinmaryland Member Posts: 1
    Hello there. I happened across your post and you just might be the only person who can help. I have a 1995 Subaru Legacy and the Check Engine Light has come on. I've gone to Advance Auto and have been told they can only read 1997 to current and the best price I received to have a mechanic read the code is $80. I really do not want to pay $80 for something that might be a $20 fix. I am in the Maryland area and was wondering if your scanner is able to read the code for a 1995 Subaru Legacy.
  • ateixeiraateixeira Member Posts: 72,587
    Well, let's see, I have this model, pictured here:

    http://www.obd-codes.com/reviews/showproduct.php/product/25

    It is an OBDII reader. There was OBD version I.

    Does anyone know when Subaru switched, and if an OBDII scanner will read codes from earlier models?

    I know that my Miata, for instance, is OBD v1, but it's a 1993.

    Maybe check to see if the port is the same on your 95 Legacy? Let me know. It's under the dash board near the driver's left knee.

    Edit: this is what the plug looks like:

    image
  • horspoorhorspoor Member Posts: 6
    Now my check engine light is on. It may be off when I start the car again. Doesn't seem to be any rhyme or reason to it. It's off as often as it's on. Just weird.
  • horspoorhorspoor Member Posts: 6
    Oh, I was looking on Ebay. Not sure how good that is, but they have a bunch of scanners. You could check with the seller and see if it's compatible with your '95 Subaru. Worth a shot anyway.
  • paisanpaisan Member Posts: 21,181
    OBDII Readers won't read OBDI The plugs aren't the same, etc. OBDI can be read by connecting the test leads to each other and counting blinks of the CEL. Each car is different so you have to check the repair manula of that car.

    '95 Imprezas were OBDII, and '96 Legacies are OBDII IIRC.

    -mike
    Motorsports and Modifications Host
  • georgejunggeorgejung Member Posts: 8
    I happen to have a 2005 Legacy wagon, same as one of the posters here - 19,000 miles on the 2.5 engine. The CEL came on, followed by the blinking cruise. I bought my car used (do I still have the power train warranty, or do I 'lose' that since it's used, not through a dealer?). I tried having the OBD II scanner, but maybe the shops' wasn't updated; no codes were read. I've been doing some searching on the net, and one site notes that Subarus use a bit different code - they recommended an OBD II with VAT. I'd be curious - do I need to go that route - but am re-assured some here have had success with the less expensive units.
    I bought this car based on what I'd thought was a stellar reputation for the company. Am I confused on that point (I've been reading a lot of folks saying Subaru is famous for 'issues' such as this - I'm not looking for another 'dependent', if ya know what I mean).

    I've checked my gas cap; I haven't checked my fuses. I expect I'm wasting my time until I get an OBD II readout - correct?
  • cptpltcptplt Member Posts: 1,075
    the factory warranty is good regardless of where you purchased it or how many owners it has had. 3/36 bumper to bumper , 5/60 powertrain. yours should still be covered. you will have to go to a dealer for the work though.
  • georgejunggeorgejung Member Posts: 8
    Thanks for the info, cptpit. I'll check tomorrow, see when I can get it in for an evaluation.

    BTW, I've been reading a lot about different OBD II scanners; most that I've checked on claim that the Subaru needs one that also has VAG (don't know what that stands for, but apparently reads more codes). I have the 2.5 normally aspirated engine; any suggestions on which I should purchase? (It'd be nice to be able to at least get an idea, for future reference, what's wrong before hauling into the dealership.) Thanks.
  • ateixeiraateixeira Member Posts: 72,587
    VAG = Volkwagon Auto Group, maybe? :confuse:
  • tompainetompaine Member Posts: 6
    I'll start off this post by saying that the dealer's service department that I have been using acknowledges that they have never seen a series of Check Engine Light (CEL) problems like the ones they have seen with my vehicle. I'm hoping that that is not simply a diplomatic way of saying I have a lemon (perhaps the only one on the roadways of Colorado).

    Let me give a little history of these problems so that I can get your collective thoughts on whether they are all related and symptomatic of a larger or missed problem or simply unfortunate isolated incidents.

    My 2002 Outback Wagon is the base model with a standard 4 cyl. engine, automatic transmission. It currently has approx. 93k miles on it.

    Back in late 2005, when I had approx. 51k miles on the vehicle, I started getting constant Check Engine lights. The dealer pulled a Code P0420 and started off by replacing a Fuel (or Oxygen) Sensor. (The dealer indicated that these were the same things.) When the CELs persisted approx. 2500 miles later, and the same code reappeared, the dealer replaced the catalytic converter. I went 15k more miles and the problem resurfaced - same code. The dealer cleared the computer and told me to drive on it some more. At 73787 miles, when the CEL and same P0420 code came back, the dealer replaced the same fuel/Oxygen sensor. Then, at 76874 (now February 2007) -- same code came back and the dealer put in a new catalytic converter.

    Up to this point, I simply got constant CELs and it did not really affect driving performance in any perceptible way. That changed this past fall, when I noticed that the vehicle would sputter and I would get intermittent engine vibrations, usually at idle or low RPM. Occasionally, the vibrations and sputtering would get more intense and sometimes at higher RPM (e.g. 2k). I also noticed that I would typically see the problems when the weather turned colder and in stop-and-go traffic or at higher altitudes (in the mountains at 9000 feet and above). The CEL would blink for 20-30 seconds and then turn constant.

    When I brought the car to the dealer in November with approx. 89k miles, at first they could not pull a code, and simply cleared the computer. The problem reappeared and technicians were able to pull a code: P0302 (cyl. 2 misfire). I was up for my 90K service, so that was done, replacing the spark plugs, and I also had them do a fuel injector flush at their recommendation.

    My problems came back in about 2 weeks and less than 2000 miles. This time the technicians pulled a P0420 code. They cleared the computer, told me to drive it some more, but warned that if the code came back I would be due for my fourth catalytic converter.

    The same symptoms persisted but when I brought the vehicle back to the dealer in late January, with approx. 93k, the techs pulled a P0302 code (the cyl 2 misfire) again. At their recommendation, I had the ignition coil assembly and ignition wires replaced. Although it was not documented, the technician also told me he did a comprehension test, which came back with normal results. They told me to use better gasoline and drive on it.

    The same problems -- engine sputtering/engine vibs, blinking CELs, etc. - came back within a week and less than 200 miles (using the better grade gasoline). The tech who worked on my car confessed that he was not sure whether the new coils and wires would solve the problem but all that the dealer can offer at this point is the recommendation that I continue to drive on it and keep putting in better grades of gasoline. Otherwise, they are out of ideas. (The service manager confessed that he did not think gasoline quality was really the issue.)

    So the short questions I have following this long post are these: Are the problems interrelated? Has something been overlooked? (A friend mentioned that loose connections with the air filter may be a culprit.) Any thoughts on what steps to take next?

    I would be grateful for any suggestions or advice.

    Thanks.
  • ateixeiraateixeira Member Posts: 72,587
    ignition coil assembly and ignition wires replaced

    I would have tried that sooner. The cat was probably a symptom of unburned fuel making its way past the cylinders that were misfiring.

    This case is far beyond my knowledge, but they have to try to find the cause rather than continue treating the symptoms.
  • paisanpaisan Member Posts: 21,181
    Hmm, seems like it could be a vacum leak, intake manifold gasket leak, intake leak of some kind. That would be my guess at this point.

    -mike
    Motorsports and Modifications Host
  • tompainetompaine Member Posts: 6
    Thanks for all your views to date. These are things that the dealer techs did not mention before. I appreciate your thoughts on this.
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