Investigating P0446 on Your 2022 Buick Envision
A P0446 code on your 2022 Buick Envision indicates an EVAP vent control circuit malfunction. The second-generation Envision uses a 2.0L turbocharged engine on a GM platform with the standard vent valve solenoid. P0449 frequently accompanies P0446 on GM vehicles as a companion code targeting the same circuit.
The basic warranty (3yr/36k) has likely expired, but the powertrain warranty (5yr/60k) covers through 2027. Federal emissions warranty (8yr/80k) extends through 2030.
Clues and Symptoms
- Check engine light with P0446
- P0449 companion code may be present
- Fuel fill difficulty
- EVAP readiness monitor incomplete
Top Suspects
- Vent Valve Solenoid Failure (High Likelihood): The primary P0446 component on GM vehicles. Replacement costs $120–$230.
- Vent Valve Wiring or Connector (High Likelihood): Corrosion at the solenoid connector from underbody exposure. Repair costs $80–$170.
- Purge Solenoid Valve (Medium Likelihood): Sticking purge valve disrupts EVAP flow. Replacement runs $100–$200.
- Charcoal Canister (Medium Likelihood): Canister saturation or degradation. Replacement costs $200–$360.
- Gas Cap Seal (Low Likelihood): Worn seal. Replacement is $10–$25.
How to Investigate
Scan for all codes. P0449 with P0446 confirms the vent valve solenoid. GDS2 at a dealer provides commanded solenoid tests. For DIY, check the gas cap seal, then inspect the vent valve connector.
Warranty and Cost
The basic warranty has likely expired, but the powertrain warranty (5yr/60k) covers through 2027. Federal emissions warranty (8yr/80k) extends through 2030. Out of warranty: $120–$360.
Safe to Drive?
Yes. P0446 doesn't affect your Envision's turbo engine performance, AWD, transmission, or any driving features.