P0011, P0021 - banjo filter removed, runs great

hey everyone. I'm new to the Subaru world, but purchased a 2005 Outback XT about 2 months ago. love it. Everything was great until I got that dreaded p0011 and p0022 code with the check engine light about 2 weeks ago. I'm no mechanic, but i can turn a wrench. I searched the forums, and removed the banjo bolt filter that leads into the turbo. I did a flush and oil change at the same time, and the code disappeared immediately. Problem solved, i thought. Code came back yesterday. stopped at oreilly and reset the trouble codes, thinking it might have just been a stored code from before, but it came back again a few miles later.

no hesitation, misfires, or other engine codes. oil level shows full after sitting overnight. turbo does NOT sound noisy or weird. when i replaced the oil, i used mobil 1 full synthetic with a mobil 1 filter (that thing is tiny). I checked this morning wit the intenion of removing the banjo bolt from the line right behind the oil fill cap, but there was no filter there. no oil leaks or other problems that I can see or hear or feel.

Car has 135k, was meticulously maintained by the previous owner for the last 100k with records to prove it. It still drives great.

I have seen threads related to the OCV, but those always seem to have misfires associated with problems with those (from what I read anyway).

Is there something I am missing. Any thoughts on where to look next.

Thanks in advance,

Justin

A. Most people here advise against Mobil1, and prefer rotella t6.

B. If I'm remembering correctly, some have solved your codes by new/cleaned intake cam gears.

I think the code related more to cam timing position than anything else.

If you are new, you might want to find the "vacation pix".

http://legacygt.com/forums/showthread.php/vacation-pix-171435.html

There are some diagnostic trees in there that will show you how to troubleshoot the codes.

Are these the only trouble codes? If there are others, they should be looked into.

These codes are not directly turbo related, but are for the variable valve system on the intake camshafts (AVCS). The most likely cause is oil related since the AVCS is oil actuated. Possible dirty or clogged oil line, banjo bolt filter or oil control solenoid valve. If your timing belt were incorrectly aligned, that could throw these codes, sounds unlikely.

When you say you checked and found no banjo bolt filter, are you sure you checked the correct place? There is a filter on the driver's side tucked behind the intake cam sprocket on the front side of the head. It is difficult to access without removing the timing belt and intake cam sprocket (a fairly big job and a real PITA). There is a member here, Hammerdown, who came up with another way to access it, but it required some grinding of the banjo bolt head to get clearance.

Also, you should check the "stickies" here, the Turbocharged Technical Forum and Walkthroughs Forum for more info. This problem has been seen by quite a few people on here.

http://legacygt.com/forums/showthread.php/help-request-avcs-related-problem-131462.html

http://legacygt.com/forums/showthread.php/remove-all-banjo-filters-222758.html

+1 for removing the OTHER banjo bolt filter. I wasn't aware of these little buggers until after I had put together my block and had it installed in my car. I was not to happy to have to pull the timing belt just to get to the other one but it's worth it. I didn't notice any misfires or anything like that, just down on power. It sounds like you're experiencing the same thing...

PS

Welcome to the Subaru world! You'll like it here. We have cookies.

Thanks for the feedback everyone. I'll work on removing that other banjo bolt filter as soon as I can. I think i just took the nut off the OCV, thinking that was it. oops.

The filter i did remove on the passenger side was pretty clogged though.

It seems to me that since I am getting the code for both banks (P0011 AND P0021), this would be something more common to the oil system overall than just the drivers side banjo bolt filter. Otherwise, it seems like the code would just be in one bank. Same thing with the OCV. It seems weird to me that both would be problematic at the same time. Is it possible that this is an oil pump issue, or would there be other codes? Of if only once ocv was bad, or one banjo bolt filter was clogged, would I get the code on both banks? Legitimate question, i just don't know enough about how these cars work.

There are no other codes being thrown.

Since you don't know for sure, IMHO the best course to take is the process of elimination, from the things more likely to cause the issue to those that seem less likely. That's why I suggested following the diagnostic trees in the vacation pix. They are usually structured this way.

The AVCS system is hydraulic and has some fine oil passages. If your oil lines are clogged with dirt, sludge, bits of metal, this can cause the AVCS system to behave strangely enough to throw codes.

The oil pump is a possible problem. Some people have reported a pressure relief valve in the oil pump stuck open. That would be very bad, since oil pressure throughout the engine would be low.

If you want to visually see what is happening, there is data available in the ECU showing you in real time what the cam angle advance is. You would need an interface and some software, which is a whole other subject.

It is probably not a good idea to drive the car around in this state, even if it "feels fine".

For oil recommendation, endless debates - there is a bandwagon around Rotella, but there are many good synthetic oils of correct spec out there. People say to avoid Mobile 1 5w-30, but there is another Mobile 1 Euro Car Formula 0w-40 that is very good. For oil filter the main thing is that you have the correct higher pressure relief valve. The Subaru OEM is fine. There are a few others. Don't worry so much about size. If you change oil at 3,750 miles as recommended, you will be putting in a new filter frequently.

I'm not following you on the Seafoam idea. That seem more like a cleaning treatment for tops of the cylinders and valves, no? How would that help clean out oil passages elsewhere in the engine?

And you did say the passenger side banjo filter was dirty. What was in it? How bad?

Not necessarily seafoam, but some kind of sludge remover in the crankcase, then another oil change.

I did look at the diagnostic tree, and it seems like i would need some more advanced diagnostic software to really do well following that tree. I can read the codes, but don't have the ability to see the real time data or detailed logs.

The passenger side banjo filter appeared to be sludge of some kind. I could not see through it, but I did not notice any debris. I seem to recall that it was gray looking.

You'll need to rule out the OCV's first by testing them. These codes pop up due to lack of oil pressure to the OCV's or faulty/sticking OCV's.

- Remove OCV, disconnect the connector and 10mm bolt and wiggle it out, may have to move the secondary coolant tank out of the way.

- Testing the movement of the valve. Take a small screwdriver and push back on the inner valve pin. Do it several times, allowing it to spring back each time. If the movement sticks or seize, replace OCV. If it moves freely without any hesitation, the movement is good.

- Testing the connection. Take a 9v battery, tape lead wires to each terminals (positive/negative), then touch the lead wires to the OCV terminals. If the valve moves, the connections are good. If nothing happens, it's bad, replace.

If the OCV's past the test, you'll need to hook up an oil pressure gauge and determine if you have enough oil pressure in the lines. If oil pressure is below normal on a cold start up (less then 60 psi), then you'll either have a clogged line or a dying oil pump.

...I did look at the diagnostic tree, and it seems like i would need some more advanced diagnostic software to really do well following that tree. I can read the codes, but don't have the ability to see the real time data or detailed logs

The passenger side banjo filter appeared to be sludge of some kind. I could not see through it, but I did not notice any debris. I seem to recall that it was gray looking.

The software would help you look for a pattern, like AVCS timing sticking at high advance, etc. Or maybe an electrical issue like bad sensor, bad ground, something like that. Assuming your sensors and wiring are OK, there are still some mechanical checks you could make.

These codes tend to get thrown when people don't change the oil enough. Since you found some sludge/junk in the passenger side banjo bolt filter, it is a fair assumption that similar junk may be found elsewhere in the engine. You could pull the oil control valves fairly easily:

http://legacygt.com/forums/showthread.php/help-p0021-intake-camshaft-position-timing-over-advanced-18887.html

See what they look like. They might need to be cleaned or replaced. FWIW, I would suggest that before running some kind of oil flush.

DTC P0021 INTAKE CAMSHAFT POSITION - TIMING OVER-ADVANCED OR SYSTEM PERFORMANCE (BANK 2) - H4DOTC

 

DTC DETECTING CONDITION:

• Two consecutive driving cycles with fault

• GENERAL DESCRIPTION

 

TROUBLE SYMPTOM:

• Engine stalls.

• Improper idling

 

STEP 1:

CHECK CURRENT DATA.

1) Start the engine and let it idle.

2) Inspect the output of AVCS advance angle and oil flow control solenoid valve duty.

 

CHECK:

Is AVCS advance approximately 0 degrees, and the oil flow control solenoid valve duty output approx. 10%?

 

IF "YES":

Check the following item and repair or replace if necessary.

• Engine oil (amount, dirt)

• Oil pipe (clog)

• Oil flow control solenoid valve (clog or dirt of oil routing, setting of spring, clog of valve)

• Intake camshaft (dirt, damage of camshaft)

• Timing belt (matching of timing mark)

 

IF "NO":

A temporary malfunction. Perform the following, and clean the oil routing:

Replace the engine oil and idle the engine for 5 minutes, and then replace the oil filter and engine oil.

As others have said,

-do check the OCVs and make sure they move freely

-take that other banjo bolt filter out using hammerhead method.

my other recommendations:

-do not wait too long to fix this or the turbo may suffer...

-get the btssm app. You will then be able to log the OCVs angles for both the driver and passenger sides. They should always be in sync. If you have these codes, I bet they are out of sync, one is either stuck, or there is really an issue in the oil flow due to the other banjo bolt filter being clogged.

The passenger side banjo filter appeared to be sludge of some kind. I could not see through it, but I did not notice any debris. I seem to recall that it was gray looking.

This is troubling and not normal. Some careful inspection of your oiling system's general health is advisable.

Welcome to the Subaru world! You'll like it here. We have cookies.

Seriously, this is a common issue, check the OCV first before suggesting other issues. Several of us have in counter this problem and it turned out to be a faulty OCV. If the OCV pass the test, then we'll look at the other possible issues.

Of course the OCVs should be tested. Nobody suggested otherwise, and the OP specifically stated he was going to do that.

Not sure how others feel about it but I always run a can of Rislone Oil Treatment through a car that's new to me or poorly maintained. It seems to do a really good job of breaking up sludge and shutting up noisy lifters. Just don't leave it (and the sludgey oil) in for a long time; maybe 1000 miles.

Based on your comment that the passenger side filter was clogged it sounds like you motor could benefit from some internal cleaning.

So, I took out both OCV's and tested them using a 9v battery with a couple lead wires. They seem to cycle well (no sluggishness). I cleaned them, oiled them and reinstalled them. Then I ran some engine flush in the oil for 4 minutes and changed the oil and filter to rotella t6. This is the 2nd time I have done this oil change procedure in the last 2 weeks, so the oil was pretty clean. first time i did it i put in mobil 1, but used shell this time. Code is still there so far, but i'm going to go to the parts store and borrow their scanner and clear the codes. One thing I noticed:

When i cracked open the bolt on top of the passenger side AVCS with the engine running, oil flowed out pretty freely. When I did the same thing on the drivers side, even after several turns on the bolt, oil just barely oozed out. One question i have is related to oil flow routing. As mentioned, I have not yet removed the banjo filter on the drivers side, but the passenger side was pretty gunked up when I removed it. I'm concerned that removing the timing belt and assorted accessories might be a bit beyond my skill level, and i'm not sure there is enough room to get that bolt out, even if I can get that nipple shaved off. Question is, is the drivers side AVCS upstream or downstream of the oil pump? in other words, would a clogged banjo filter on the drivers side impede oil flow to the AVCS, or does oil flow from the AVCS to that banjo bolt?

The other thing that does not make sense is why I'm getting both codes if oil seems to flow fine on the passenger side.

forgive my ignorance if i am assuming something incorrectly. I don't know a ton about this kind of stuff, which is why I'm hoping a couple of you experts here will have some ideas.

If I were to attempt to test the oil pressure, where would I connect the gauge?

One question i have is related to oil flow routing. As mentioned, I have not yet removed the banjo filter on the drivers side, but the passenger side was pretty gunked up when I removed it. I'm concerned that removing the timing belt and assorted accessories might be a bit beyond my skill level, and i'm not sure there is enough room to get that bolt out, even if I can get that nipple shaved off.

Link to how to move DS banjo filter bolt, without remove rear timing cover & everything before it. http://legacygt.com/forums/showpost.php?p=1326330&postcount=158

Question is, is the drivers side AVCS upstream or downstream of the oil pump? in other words, would a clogged banjo filter on the drivers side impede oil flow to the AVCS,

Yes, the oil flows out of the DS head, into & through the banjo filter bolt on it's was to the AVCS.