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2010 Legacy 3.6R Limited
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Discussion Starter #1 (Edited)
I was heading home earlier and got a Check Engine flashing, VDC off solid, BRAKE flashing, and Cruise flashing light. Check engine ended up staying on with VDC, but the other two kept flashing. Stopped and read the codes quick and got P0301, P0303, and P0305. What would cause an entire bank to register misfires? (It does shudder if you are in P or N and rev up to 2,300 or so.)

It doesn't feel or smell funny, it's still responsive and fast, no overheats, ****... feels normal outside the weird shudder mentioned.


488744
 

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2013 3.6R Limited
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843 Posts
One possibility is a failed oxygen sensor.
 
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2010 Legacy 3.6R Limited
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Discussion Starter #3
Wouldn't that throw its own code (like a bank 1 lean or something)?
 

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'03 Outback H6-3.0 Black Granite Pearl, base model with cold weather package and cloth seats.
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or a failed fuel pressure regulator. resulting in one side running richer than the other side.
 

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2010 Legacy 3.6R Limited
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Discussion Starter #5
I have another VAGCOM cable coming on Wednesday, then I'll bring some logs, but this was just weird with that many lights and a whole bank going bad without actually going bad. I just put a tank of gas in it, too. Don't think it could be fuel related on that end, could we?
 

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2010 Outback 3.6R 2014 Legacy 2.5i 2003 Legacy L special edition (retired to backup)
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inspect pcv and blowby hose for hardness and replace if hard. ditto for brake booster hose
 

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'10 3.6R Outback Limited, 2zr swapped Toyota Yaris track toy, '12 Mazda3 skyactive
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My money is on your exhaust VVT solenoid on bank 1.

I posted about having the same issue last year. Solenoid tested within specs but a new one solved the problem.

I was able to diagnose it using SSM software and comparing the solenoids from bank 1 and 2 and seeing the differences. The bad solenoid was bouncing around and not as stable as the good side. When I put the new one in the vamues stabilized.
 

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2010 Outback 3.6R 2014 Legacy 2.5i 2003 Legacy L special edition (retired to backup)
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^ you can remove them and dip them in solvent to clean them up. Put them in a cup and fill it with solvent until the oil control valve is completely submerged and then use a 9V battery to actuate it in the solution a few dozen times
 

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2010 Legacy 3.6R Limited
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Discussion Starter #9
I can't upload a ZIP of my logs anymore. This makes me sad. I'll try to get some charts put together to attach in this thread.
 

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2010 Outback 3.6R 2014 Legacy 2.5i 2003 Legacy L special edition (retired to backup)
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save your CSV file as a .txt file in excel and you will be able to upload it here.
 

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2010 Legacy 3.6R Limited
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Discussion Starter #11
We've got a discrepancy between banks of about 5% on A/F learning, and a few more percent swing at various times. I also logged VVT angles for both banks and both intake and exhaust, just not included in this chart for cleanliness.
489052
 

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2010 Legacy 3.6R Limited
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Discussion Starter #12
Ah you had a good idea. They're just renamed though, so just change .txt to .csv if y'all need to.
 

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2010 Outback 3.6R 2014 Legacy 2.5i 2003 Legacy L special edition (retired to backup)
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+1 for Variable Valve Timing control.... you can remove the solenoids/actuators and soak them in some heavy duty cleaner solvent...I am going to do mine this weekend and stick them in an ultrasonic cleaner
 

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'10 3.6R Outback Limited, 2zr swapped Toyota Yaris track toy, '12 Mazda3 skyactive
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I'm unable to properly view your data logs
 

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^ right click, save target as, save file. Go to file and rename to .csv and open in excel

489114


and you can open it

489115
 

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2002 Pair: 3.0 VDC Wag & 2.5 Limited Sedan
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Wouldn't that throw its own code (like a bank 1 lean or something)?
minor misfires seem to pop up before a more definitive code.

good you are getting logs though. (as someone might see the cause).
 

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I didn't have any problem viewing them after replacing the .txt with .csv. That said, I also did not see any odd behaviours in the intake and exhaust valve timing.

In all three logs there was only one single instance of a misfire ("roughness"), and that was in the WOT-to-60 log. Haven't looked at the other parameters at the time to see if there might be an obvious explanation.
 

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at idle AF learn is -7 that seems a bit odd at idle
 

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As previously mentioned, the VVT Solenoid on that bank. The rough idle cold, and shudder come first. In my case, the P0014 showed up at the same time as the random misfires on all three cylinders of the corresponding bank, however, sometimes the misfires show up first. - All depends on how much the oil control valve/solenoid for that bank clogged or sticking.

What I hadn't realized over time, was that the engine's sound under load had slightly changed. After replacing the solenoid, it was immediately apparent in the sound under load when accelerating. 'Supposedly' you can remove the valve, clean it really well, and reinstall it, however, for $35 or so, I chose to install a new one. That was a couple months ago, and she's been purring like a kitten since, and idles/accelerates butter smooth.

You can test the theory by swapping the valves between the two banks, if the codes switch to the P0302, P0304, and P0306, it's absolutely the VVT Oil Control Valve or solenoid. - Thought occurred that there are two(2) very similar looking devices down at the lower front corner, the VVT Solenoid/Oil Control Valve is the one that pulls out towards the frame rail. (It takes some effort to pull it out, they O-Ring seals quite tight).
 

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Subaru OEM valves are not cheap, ia m going the clean that thing first route
 
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