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Old 01-08-2013, 02:21 PM   #1
Scooby Newbie
Member#: 118170
Join Date: Jun 2006
Chapter/Region: South East
Location: Chattanooga, TN
Default 2004 STI P0021 diagnostic help

First, allow me to say that I have searched for my issue on the forums before posting this. If someone finds my issue in another thread, please share and I apologize for creating duplicate content.

My car is throwing a P0021 error code. I know that this has been talked about all over the forum but to refresh, here is the translation...
"A" Camshaft Position - Timing Over-Advanced or System Performance (Bank 2)
The car: 2004 Subaru WRX STI with 54,000 miles

The story: My car lost almost all oil pressure on the interstate at about 80 MPH. The gauge read about 4 lbs. I pulled over but there was already a HUGE knock. I was able to drop the skid plate and oil pan to replace the rear 3 bearings on the crank shaft. The last one couldn't be reached but it was actually still tight. The other three were scorched. Oil was changed about 5 times in a row (after running the engine for a SHORT time). Even after the second oil change, the oil looked like glitter. Was finally able to change the oil and not be able to see metal in it. The large knock went away. It was replaced by a knock in the middle power band. That's where the P0021 error code comes in. I think that the driver's side cam gear or solenoid is still blocked by something.

I removed both solenoids to check them before tackling the AVCS cam gears. The driver's side solenoid came out with very minor oil in it. It still seems to be in working order. When the other solenoid popped out, oil came out with it. Now I seem to think that the driver's side solenoid isn't getting any oil. Could this cause my error? I want to solve this possible problem before trying to replace the AVCS timing gears. The line to the solenoid seems to be EXTREMELY tight. I had a breaker bar on that sucker but didn't want to literally break it. So here I am.

Does anyone have any information that might shed some light on this situation? How can I trace the oil line for the solenoid?
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Old 01-09-2013, 01:59 PM   #2
Scooby Newbie
Member#: 118170
Join Date: Jun 2006
Chapter/Region: South East
Location: Chattanooga, TN

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Old 01-09-2013, 02:33 PM   #3
Scooby Newbie
Member#: 262684
Join Date: Nov 2010
Location: Reading, MA
2015 Impreza Sport


you searched? it's pretty widely known that banjo bolt filters collect debrise thats in the oil. typically clogging after either a blown turbo or a spun bearing. you need to remove both filters, clean them, and reinstall- they're blocking oil flow to the solenoids and causing more advance than the ecu calls for.
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Old 01-09-2013, 02:57 PM   #4
Scooby Specialist
Member#: 170948
Join Date: Feb 2008
Chapter/Region: South East
Location: Pembroke Pines, FL

When I got this code I did the following:

1) Remove all banjo bolt filters. One behind the passenger head, one going into passenger AVCS solenoid, one going into driver side solenoid, and the one on the front driver side head. My filters had actually broken and came out in several pieces.

2) Removed both AVCS solenoids, cleaned them thuroughly with electrical parts cleaner, relubed with fresh oil and reinstalled. My issue was plastic pieces of the filter limiting the movement of the spring in the solenoid. When cleaning, compress the springs and spray the cleaner to thuroughly take out any crap that might be in there.
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Old 07-02-2013, 09:31 PM   #5
Scooby Newbie
Member#: 353507
Join Date: Apr 2013
Location: Louisville, Kentucky
2004 WRB WRX STi


How do you remove the solenoid I took the bolt out of the top and both on the sides and it wouldn't move how do I get it to come out so I can clean it
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Old 07-15-2013, 08:40 PM   #6
Scooby Newbie
Member#: 362431
Join Date: Jul 2013
Default P0011 code Subaru WRX 2008 stock

I have received this code several times now and the mechanics are stumped.
The car drives beautifully, no detrimental effects to the turbo or performance otherwise. Most recently, the check engine light came on 120 miles after having work done and the code reset. I was getting on the freeway in 5th gear and let the RPMs slip below 2,000 when the light came on. The vehicle occasionally will send minor vibrations while at a stop, but it's not alarming.

My WRX is an '08 with 72,000 miles and no modifications. Prior to the check engine light coming on, the timing belt was replaced and oil changed regularly. Since the P0011 code, I've had both camshaft position sensors replaced (banks 1 and 2), as well as the oil changed again.

Please advise as to what direction I should go in. Is it just a timing issue that can be resolved with the high quality tools of a dealership, or am I looking at serious maladies. Thanks!
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