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My Check engine light jsut came on.so now what


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To answer your question properly we will need to know what the exact code is. Auto Zone, advance auto, or other local parts stores should be equiped with the code scanner. Go there, they will generally do it free. Get the P code and report back...

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any recent work done in the past year?

 

yep, find out what the code is. autozone and advanced auto parts check the code for free. here's a hint - don't tell us what the guy behind the counter "thinks" it is, tell us the exact codes from the print out/scanner. more often than not we will know more than the dude behind the counter does about subaru's. most likely it'll be something simple to fix that is "common" enough to have been seen before:

 

cylinder misfire - new spark plug wires, easy.

knock sensor - the housings crack - get another one, it's one 12mm bolt to replace it.

O2 sensor - you're getting to the age where it's not a bad idea to replace the front one anyway. just requires a 22mm wrench, that's it...oh and two hands!

cam and crank sensors aren't that rare either - replacement is very easy.

EGR - i hate them, but it won't take much to fix that either.

 

so...report to us what the scanner tells you and we'll help you fix, probably fairly cheap (a whole lot cheaper than taking it to a mechanic).

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[...]What should/can I do to get the light off. What has to be replaced, cleaned or ????
Wecome to the forum. As has already been suggested, have the OBD-II trouble code read, and get back to us with it. (If the light came on after a recent gas fill up, try tightening the gas cap. :) )
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Ok I went to Checker..the code was p0304 The girl said 4th plug misfiring..So I have looked at where the plug is, is there a trick to getting at it? Looks like maybe from underneath is easier than from the top. I have to wait for the engine to cool off anyway so I may tackle this in the A.M. I am in AZ and it's 110 in the shade.

 

Thanks for all the other tips where are all those things (knock sensor, O2 sensor,cam and crank sensors,etc.) A picture would be worth a thousand words; I am new to Subaru's engines. I have have done plenty of tune-ups and brake jobs on Honda's.. Is there a place on line where I can download (for free)a shop manual or general schematic for the Outback.

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One test is swap the plug wire with it's mate. Inspect wire to coil and wire to plug connections for corrosion if you do it. If the misfire code follows the wire, you may be hot on the trail. If you replace the plug wires, buy oem wires. Plugs should be oem recommended types, such as NGK.

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Can I get some help on the location of the other items mentioned in case I have to change those in the future.

 

And any advise on getting the plug out would be helpful it looks like it's really hard to get at it. I will try and switch the plug wires first to see if the problem follows the wire.

 

Again, anyone have a site for downloading a Subaru shop manual or schematics???

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with 50k miles a bad spark plug could certainly be the misfire culprit, just be sure to get NGK BKR6E-11 plugs (that's what the dealer will give you for your car too, just in a Subaru box). If you're replacing wires, get some from the dealership.

OK, getting the plugs out of a DOHC motor, however, isn't as easy as..say, a Honda. here's my reply from another thread, slightly edited for your situation.

little tip I picked up at work (I'm a beginning Subaru dealer technician): unbolt the pitching stopper dog-bone shaped thingy from behind the motor (14mm, if I remember correctly) and swing it up away from the motor, remove the nuts from the two motor mounts (also 14mm, I think), then position a jack and block of wood or something similar under the front of the motor (not the oil pan, but the block itself) and lift the motor a couple inches. you can go like 3, maybe even 4 inches up, just don't start actually pulling any hoses or anything. just that little bit of lift will give you all sorts of extra access to the plugs.

 

a little variation for pulling a cylinder head (or even for doing plugs on one side of the motor at a time...makes more clearance than lifting the whole motor at once): undo the pitching stopper and this time only one motor mount (on the side that you're working on). lift the motor a couple inches, it will start to cock over to one side, and slip a large socket that you won't be using (or piece of wood, or whatever) between the motor mount and the cradle. Now you've got that side of the motor propped up a little, and pulled a little away from the frame rail...pretty sweet.

~Erik~

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An update. I switched the plug wires 3 and 4 and went back to have the error code checked again.. NO change it still showed 4 misfiring but didn't add three?? so I had her erase the code. Started it up and no engine check light. I drove it home 3 miles, still no check engine light and will drive it around for a day or two with the wires switched if the light stays off, I will then switch the wires back and see what happens. Maybe it was only a loose wire/connection and moving them has fixed it??? Too much to hope for????

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it's always a possibility that it was a fluke event that caused the code, or it may just be something that isn't big enout for the computer to take immediate notice of. some codes take mutiple consecutive occurances to set the "check engine" light. for being on a budget, this was probably a good idea, just to really confirm the code wasn't just a fluke before you go ahead and start throwing parts at it. oh, and leave the wires on reversed, so if/when the code comes back, you'll be able to see if the misfire follows the wire.

~Erik~

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I plan on leaving the wires reversed for a few days of driving if the light doesn't come on I figure it was a fluke and not anything really wrong. Then I plan on switch back just to keep the numbers on the wires and cylinders matched correctly. Cause later I may forget that I switch them. Does sound like a reasonable plan?

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If the wire(s) or plug (s) are bad why wouldn't the code show again fairly quickly?? I don't want to drive around and slowly be killing my cat due to misfiring and fuel going into the cat. But I don't want to replace stuff that doesn't need it either.

 

Also I brought some plugs two years ago, autolites 3924's and that's what I have been running gas mileage 22/23 MPG. Seems to be OK? But I have been reading that one should only use OEM NGK's. This is on a 99 Outback Limited 2.5.

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If the wire(s) or plug (s) are bad why wouldn't the code show again fairly quickly?? I don't want to drive around and slowly be killing my cat due to misfiring and fuel going into the cat. But I don't want to replace stuff that doesn't need it either.
If there was sufficient corrosion on the plug wire at either end to cause a weakened spark, moving the wire may have temporarily removed or broken through it; it can reform, sometimes quite a bit later. In the meantime, if the code doesn't recur, then there probably isn't enough misfiring (there's always some) for the ECU to see, or to damage the cat.

 

 

Also I brought some plugs two years ago, autolites 3924's and that's what I have been running gas mileage 22/23 MPG. Seems to be OK? But I have been reading that one should only use OEM NGK's. This is on a 99 Outback Limited 2.5.
I'd suggest replacing the Autolites. On the resistor type, I've seen the resistance go up significantly in value as the plug is used; that eventually leads to misfire.
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Using NGK plugs is the best way to go in my book. Other plugs can work but they can cause trouble like this also. Some other things that can cause this kind of trouble is the knock sensor being too sensitive and carbon buildup in the cylinders.

 

To get at the hard to reach plugs you may have to remove some accessories or come at it from below the engine.

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Thanks for all the info. I am going to watch it for now. Which wires in a few days and maybe install new plugs after that. I'll post what happens in a week or so.

 

Great site, good folks, good info fast responses..I'll be back to help or ask more questions.

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If the wire(s) or plug (s) are bad why wouldn't the code show again fairly quickly??
we can't guess what happened, but basically what he said. corrossion inside the boot...if it allows corossion once it will likely happen again. arcing...reseating may have helped...just random thoughts, not that yours did either of those, but it can happen.

 

But I have been reading that one should only use OEM NGK's. This is on a 99 Outback Limited 2.5.
correct, NGK's on the EJ series engines, particularly yours. these, particularly the motor you have too, are sensitive when it comes to plugs and wires.

 

you could get away with another 5 years, so who knows, time...and the handy CEL will tell. no matter if it's 5 months or 5 years from now, be sure to use Subaru only spark plugs wires on this EJ25, no matter what anyone tells you.

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