Subaru Tribeca B9 P0021 Due to Clogged AVCS Oil Filter Screen

When oil flow to the AVCS components is restricted, the filter screen inside the oil feed banjo bolt may be the culprit. To verify this, locate the oil feed line banjo bolt on the Bank 2 cylinder head. Remove the bolt and extract the small mesh filter screen contained within. Inspect the screen under bright light for physical debris, varnish, or oil sludge buildup that would obstruct the oil passage. If the screen is visibly blocked, this confirms a restriction in the hydraulic circuit supplying the camshaft phaser.