Investigating P0446 on Your 2022 Buick Enclave
A P0446 code on your 2022 Buick Enclave points to an EVAP vent control circuit malfunction. The Enclave uses a 3.6L V6 on a GM platform with the standard vent valve solenoid controlled by the ECM. On GM vehicles, P0449 frequently accompanies P0446 as a companion code targeting the same vent valve solenoid circuit.
The basic warranty (3yr/36k) has likely expired, but the powertrain warranty (5yr/60k) should still be active through 2027. The federal emissions warranty (8yr/80k) covers EVAP through 2030.
Clues and Symptoms
- Check engine light with P0446
- P0449 companion code may also be present
- Fuel fill difficulty
- EVAP readiness monitor incomplete
Top Suspects
- Vent Valve Solenoid Failure (High Likelihood): The GM vent valve solenoid is the primary P0446 culprit. Located near the charcoal canister. Replacement costs $130–$240.
- Vent Valve Wiring or Connector (High Likelihood): Connector corrosion from underbody exposure. Repair costs $80–$180.
- Purge Solenoid Valve (Medium Likelihood): Sticking purge valve disrupts EVAP flow. Replacement runs $110–$210.
- Charcoal Canister Saturation (Medium Likelihood): Canister degradation after years of use. Replacement costs $200–$370.
- Gas Cap Seal (Low Likelihood): Worn seal. Replacement is $10–$25.
How to Investigate
Scan for all codes—P0449 alongside P0446 strongly points to the vent valve solenoid. Check the solenoid connector for corrosion. GDS2 at a dealer provides commanded solenoid testing. For DIY, test the vent valve with 12V applied directly.
Warranty and Cost
The basic warranty has likely expired, but the powertrain warranty (5yr/60k) covers through 2027. The federal emissions warranty (8yr/80k) extends through 2030. Out of warranty: $130–$370.
Safe to Drive?
Yes. P0446 doesn't affect your Enclave's V6 engine, transmission, AWD, towing, or three-row passenger safety.