Tracking P0446 on Your 2024 Mazda CX-90
A P0446 code on your 2024 Mazda CX-90 signals an EVAP vent control circuit malfunction. Mazda's flagship three-row SUV offers the all-new 3.3L Skyactiv-G turbo inline-six (340 hp) or 2.5L PHEV powertrain. Both use a canister vent shut valve for EVAP management, with the PCM detecting a circuit fault.
Under full Mazda warranty, this is a dealer repair at no cost. As a first-generation vehicle with an all-new platform and powertrain, first-year calibration updates are common.
Symptoms Present
- Check engine light on with P0446
- Fuel fill difficulties
- EVAP readiness monitor incomplete
- Possible companion codes
Likely Causes
- Canister Vent Shut Valve Defect (High Likelihood): Manufacturing variation on the new platform. Warranty-covered.
- PCM Software Calibration (High Likelihood): First-generation model with all-new powertrain — EVAP monitoring calibration updates are very likely available. Warranty-covered.
- Purge Solenoid Valve Issue (Medium Likelihood): New engine architecture means new purge valve configuration. Warranty-covered.
- EVAP System Assembly Issue (Medium Likelihood): New platform assembly — potential for factory connection variations. Warranty-covered.
- PHEV EVAP Monitor Timing (Low Likelihood): If PHEV equipped, the engine runs intermittently, affecting EVAP monitor execution frequency. Warranty-covered.
What to Do
Schedule a Mazda dealer appointment. Under warranty, Mazda IDS diagnostics, software updates, and component replacements are all free. The all-new platform requires dealer-level tools for proper diagnosis.
Full Warranty
Your 2024 CX-90 is covered by Mazda's 3-year/36,000-mile basic, 5-year/60,000-mile powertrain, and federal emissions warranty (8yr/80k). All EVAP repairs are free.
Safe to Drive?
Yes. P0446 doesn't affect your CX-90's inline-six turbo or PHEV powertrain, 8-speed automatic, i-ACTIV AWD, towing capability, or luxury features.