P0021 on Subaru: How to Diagnose & Fix
Intake Camshaft Position Timing - Over-Advanced or System Performance (Bank 2)
3 Subaru models · 3 documented issues · 1 critical · $50-$3,500 repair
P0021 on Subaru by model: symptoms, diagnosis and fix
The FA20 engine in the BRZ consumes oil at elevated rates during high-RPM driving, spirited canyon runs, and track use. The engine design with direct injection and high compression (12.5:1) combined with the oil-fed variable valve timing system means oil consumption increases significantly when the engine is frequently operated above 5,000 RPM. Consumption rates of 1 quart per 1,000-2,000 miles are reported by owners who drive aggressively. The narrow oil galleries in the FA20 make proper oil level maintenance critical.
Common Symptoms
- Oil level drops noticeably after spirited driving or track days
- Oil level normal during city/highway commuting but drops during performance driving
How to Fix
Check oil level before and after every spirited drive or track day. Carry an extra quart of 0W-20 (OEM spec) or 5W-30 (commonly used upgrade for track use). For track cars, install an oil catch can (Radium Engineering 20-0255-02 or Crawford Performance V3) to reduce oil vapor entering the intake. Consider an oil cooler for track use. The 2013 BRZ owner's manual says to contact a dealer if the engine uses more than 1.1 qt every 600 miles.
What you need to fix it
Only diagnosis- and fitment-reviewed repair parts are linked here.
- Genuine Subaru SOA427V1310 synthetic 0W-20 engine oil, 1 quart
2013-2020 Subaru BRZ FA20 according to the live product listing; for 2021 or any modified/track-use engine, confirm the current owner manual and oil specification before purchase.
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Sources for this issue (2)
The turbocharger oil-feed line on the EJ255 uses a banjo (union) bolt containing a fine mesh screen meant to keep debris out of the turbo. As the engine ages or oil-change intervals stretch, sludge and carbon clog the screen and starve the turbo of oil. The turbo bearing then overheats and fails — the shaft can break and the compressor wheel disintegrate, sending metal debris into the oil pan, oil cooler and engine bearings, often destroying the engine. Subaru's service bulletin for turbocharged models directs technicians to check this screen for obstructions whenever a turbo is replaced, and to clean it or replace the banjo bolt (the screen comes only with the bolt, P/N 14445AA090) if it is blocked.
Common Symptoms
- Loud whine, whistle or grinding from the turbo
- Blue smoke from the exhaust
- Sudden loss of boost/power
- Knocking or low oil pressure
- Metallic debris found in the oil pan or screen
How to Fix
On EJ255 turbo Foresters, proactively remove and clean (or replace with a new screened banjo bolt, P/N 14445AA090) the banjo-bolt oil-supply screen at the turbo oil-feed line and keep to short synthetic-oil intervals. At the first sign of turbo whine, blue smoke, or low oil pressure, inspect the screen and oil-feed line before further driving. A failed turbo requires turbo replacement plus a thorough oil-system flush; if debris reached the bearings, engine teardown may be needed.
What you need to fix it
Only diagnosis- and fitment-reviewed repair parts are linked here.
- Genuine Subaru 14445AA090 Turbo Oil-Supply Union Bolt with Screen
correct screened union bolt when inspection finds an obstructed or damaged screen Fitment/availability: 2009-2013 Forester XT EJ255 turbo branch explicitly listed; confirm VIN and feed location Fitment/availability: in stock with Add to …
- Genuine Subaru 803910050 Small Turbo Oil-Feed Copper Washer Pair
new sealing washers required when the screened union bolt is serviced Fitment/availability: 2009-2013 Forester XT explicitly listed; two washers supplied, confirm the serviced banjo connection Fitment/availability: in stock with Add to C…
- Genuine Subaru 15192AA590 Turbocharger Oil Pipe
replacement feed pipe only when restricted, damaged or not cleanable Fitment/availability: 2009-2013 Forester 2.5-liter turbo XT catalog branch; confirm VIN Fitment/availability: ships in 1-3 business days with Add to Cart live when revi…
- Genuine Subaru 14411AA710 Turbocharger Assembly
replacement only after turbo failure and its lubrication cause are confirmed Fitment/availability: 2009-2013 Forester XT turbo branch; confirm VIN and current supersession Fitment/availability: ships in 1-3 business days with Add to Cart…
- Tokyo Roki 15208AA100 Black Oil Filter
engine oil filter used with the correct oil service after contamination inspection Fitment/availability: Retailer specifies all turbocharged EJ engines, including the 2009-2013 Forester XT EJ255 branch Fitment/availability: in stock with…
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Sources for this issue (4)
- Turbo Failure (clogged Banjo Bolt Filter) — Subaru Outback/Forester forumforum
- What's your take on the oil supply screen in the banjo bolt? — Subaru Forester Owners Forumforum
- The Dreaded Subaru P0011 and P0021 DTC Codes, Don't Let Them Wreck Your Turbo — MotoIQarticle
- Subaru turbo filter (turbo oil-supply banjo bolt screen) — Vehicle Service Prostsb
P0011 sets when the Bank 1 (passenger-side) intake camshaft is advanced beyond the ECM's commanded position — the AVCS phaser is stuck advanced or the ECM can't control it. On the Outback this is almost always oil-related: low or dirty engine oil, or the passenger-side intake oil control valve (OCV) sticking, or the classic Subaru issue of clogged filter screens inside the banjo bolts that supply oil to the AVCS solenoids. The ECM drives the oil-flow control solenoids mounted on the valve covers, which move spool valves to route oil pressure into the cam phaser; any restriction over-advances or locks the cam. It often appears in extreme cold (thick cold oil starves the AVCS) and on cars with stretched oil-change intervals. A useful test is swapping the Bank 1 and Bank 2 intake OCVs and seeing whether the code follows to P0021.
Common Symptoms
- Check engine light
- Rough or unstable idle
- Hesitation or slight loss of power
- Worse in very cold weather
- Minor fuel-economy drop
How to Fix
Check oil level and condition first and change with spec 0W-20 synthetic if degraded. If the code persists, remove and clean/replace the AVCS banjo-bolt filter screens and replace the Bank 1 intake oil control valve (OCV, ~$95-350 OEM) — a straightforward job. Inspect the OCV connector/harness for open or short. Reset ECM VVT learned values after repair.
What you need to fix it
Only diagnosis- and fitment-reviewed repair parts are linked here.
- Genuine Subaru 10921AA231 Oil Control Valve
OCV only after the Subaru diagnostic path proves the valve fault Fitment/availability: 2013-2017 Outback 2.5-liter FB25 branch; confirm VIN and bank/position Fitment/availability: Add to Cart live when reviewed
- Genuine Subaru 10921AA23B Oil Control Valve
later OCV only after the fault is proven Fitment/availability: 2018-2019 Outback 2.5-liter FB25 branch within this card; current replacement for 10921AA23A, confirm VIN and position Fitment/availability: ships in 1-3 business days with A…
- Genuine Subaru 14451AA050 Cam-Carrier Oil Filter
filter only when the applicable TSB diagnostic procedure identifies restriction Fitment/availability: cataloged for the FB25 Outback branch; quantity and position are procedure/VIN dependent Fitment/availability: ships in 1-3 business da…
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Sources for this issue (3)
P0021 code reference
General diagnostic-code context. The code alone does not confirm a cause for your vehicle; use the applicable issue card and its sources.
Frequently asked questions
What does P0021 mean on a Subaru?
P0021 stands for "Intake Camshaft Position Timing - Over-Advanced or System Performance (Bank 2)." P0021 means the engine computer detected that the intake camshaft on bank 2 is timed too far advanced and won't return to its commanded position. Most modern engines use variable valve timing (VVT), where an oil-pressure-driven actuator rotates the camshaft to optimize power and efficiency; the PCM compares the camshaft's actual position to its target. When the cam stays over-advanced beyond an acceptable limit, this code sets. Bank 2 refers to the side of the engine that does not contain cylinder number one. You may notice rough idle, reduced performance, or lower fuel economy. On Subaru it is documented across 3 models: BRZ, Forester, Outback.
What are the most common causes of P0021?
The most common causes of P0021 are: Dirty or low engine oil restricting the VVT system, Stuck or failed camshaft oil control valve (VVT solenoid) on bank 2, Clogged VVT solenoid screen or oil passage, Faulty camshaft position actuator / phaser, Wiring or connector fault at the VVT solenoid, Camshaft or crankshaft position sensor problems, Worn timing chain, guides, or stretched chain altering cam timing. The specific cause varies by vehicle.
How much does it cost to fix P0021 on a Subaru?
Published repair estimates on Subaru range from $50 to $3,500 depending on the model and root cause. If an issue mentions a recall or campaign, check your VIN with the manufacturer or NHTSA and confirm eligibility and coverage with a dealer.
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Content compiled with AI assistance using NHTSA complaints, TSBs, and owner reports. May contain errors. Always verify with your vehicle's service manual.