Tracking P0446 on Your 2024 Mercedes-Benz GLC
A P0446 code on your 2024 Mercedes-Benz GLC (X254) signals an EVAP vent control circuit malfunction. The second-generation GLC uses the M254 2.0L turbo with 48V EQ Boost (GLC 300) — a significant upgrade from the previous X253's M264. The engine control module has detected a circuit fault in the canister shut-off valve.
Under full Mercedes-Benz warranty, this is a no-cost dealer repair. The redesigned X254 may have first-year software calibration refinements available.
What You're Seeing
- Check engine light with P0446
- Fuel fill issues at the pump
- EVAP monitor incomplete
- Possible companion codes
Likely Causes
- Canister Shut-Off Valve Defect (High Likelihood): Manufacturing variation in the vent valve. The primary P0446 suspect on all Mercedes models. Warranty-covered.
- Engine Control Module Software (High Likelihood): First-year X254 EVAP calibration may need refinement. A dealer reflash is the quickest resolution. Warranty-covered.
- N80 Purge Valve Issue (Medium Likelihood): The purge valve affects EVAP system operation. Factory defect possible on a new vehicle. Warranty-covered.
- EVAP Circuit Connector (Medium Likelihood): Factory connector seating issue in the redesigned X254 underbody. Warranty-covered.
- Fuel Tank Pressure Sensor (Low Likelihood): Sensor deviation on the new platform. Warranty-covered.
What to Do
Schedule a Mercedes-Benz dealer appointment. Under full warranty, XENTRY diagnostics, software updates, and any component replacements are covered at zero cost.
Full Warranty Coverage
Your 2024 GLC is covered by Mercedes-Benz's 4-year/50,000-mile warranty and the federal emissions warranty (8 years/80,000 miles). All EVAP repairs are free.
Safe to Drive?
Yes. P0446 doesn't affect your GLC's M254 turbo engine, 48V mild hybrid, 9G-TRONIC automatic, 4MATIC AWD, or any luxury features. Full crossover capability is maintained.