I have the Toyota Four Horsemen lights (Check Engine, Skid, TRAC OFF, VSC OFF). OBD code is P0456 (very small leak). Purge VSV valve is closed and doesn't leak via a vacuum gauge and smoke test. I closed the system by plugging the filter exhaust (beyond the Vent valve, see red line) and ran a smoke test. Smoke test boundary was from the red line to the PCV valve at the front of the car. System passed the smoke test, there was no leak. Anyone encounter this? Could it be the vent valve leaking? How do you command the vent valve to close without a scanner tool? Can you back pin the canister pump module harness?