We've seen a steady increase in AVCS camshaft position sensors on EJ20 engines leaking oil into the sensor's plug. This can result in contamination of the main engine wiring loom and some cases, the main loom back to the ECU harness. The AVCS camshaft position sensor pickups are immersed in oil and the combination of heat and life cycle reduces the protective oil seal in the sensor cap resulting in a slow and steady leak back. Subaru no longer produce the original engine wiring looms so aftermarket repair or replacement existing loom is currently the option.
To avoid or reduce risk to wiring looms we recommend replacing AVCS camshaft position sensors on cars which have original sensors fitted.