Solving the P0446 on Your 2023 Subaru Legacy
A P0446 code on your 2023 Subaru Legacy signals an EVAP vent control circuit malfunction. The seventh-generation Legacy (BN platform) with the 2.5L FA25 or 2.4L FA24 turbo boxer engine uses a canister vent control valve for evaporative emissions. The ECM has flagged an electrical fault in this circuit.
For a 2023 model under Subaru warranty, this code leads to a straightforward dealer resolution at no cost.
Symptoms Noted
- Check engine light on with P0446
- Fuel nozzle clicking off during refueling
- EVAP monitor not completing
- May appear with companion codes
Likely Causes
- Canister Vent Control Valve Failure (High Likelihood): The vent valve can fail electrically even on relatively new vehicles. Primary P0446 suspect. Warranty-covered.
- Vent Valve Connector or Wiring Issue (High Likelihood): A factory or early-wear connector issue. Warranty-covered.
- ECM Software Calibration (Medium Likelihood): Updated EVAP monitoring software may be available. Free dealer reflash.
- Purge Control Solenoid Issue (Medium Likelihood): Boxer engine's unique purge layout. Warranty-covered.
- Gas Cap Issue (Low Likelihood): Quick check. Warranty-covered.
What to Do
Visit a Subaru dealer. Their SSM4 system provides bidirectional vent valve testing and TSB lookups. Under warranty, the dealer handles everything.
Warranty Coverage
Your 2023 Legacy is within Subaru's 3-year/36,000-mile basic warranty and the federal emissions warranty (8 years/80,000 miles). This repair is free.
Can I Drive With P0446?
Yes. P0446 is an emissions code. Your Legacy's boxer engine, CVT, and AWD are completely unaffected.