Decoding P0446 on Your 2020 Mercedes-Benz GLE
A P0446 code on your 2020 Mercedes-Benz GLE (W167) indicates an EVAP vent control circuit malfunction. The first-year W167 generation offered the M264 2.0L turbo (GLE 350) or M256 3.0L turbo six with 48V EQ Boost (GLE 450/580). The engine control module has detected a circuit fault in the canister shut-off valve.
At five to six years old and as a first-model-year vehicle, your GLE is past the basic warranty and entering the age window where EVAP component degradation becomes more likely. The federal emissions warranty still provides coverage.
Clues Gathered
- Check engine light on with P0446 stored
- Fuel nozzle shutting off during fill-ups
- EVAP readiness monitor incomplete
- May appear with P0441 or P0456
Leading Causes
- Canister Shut-Off Valve Degradation (High Likelihood): After five-plus years, the valve's solenoid and seal wear from thermal cycling. First-year W167 components may have slightly higher failure rates. Parts $90–$195, labor $135–$265.
- Valve Connector Corrosion (High Likelihood): Years of road exposure corrode the underbody connector. The GLE's SUV ground clearance helps, but salt and moisture still penetrate. Repair costs $75–$175.
- N80 Purge Valve Wear (Medium Likelihood): The N80 purge valve degrades with heat exposure and cycling. A weak purge valve disrupts EVAP balance. Parts $105–$225, labor $125–$255.
- EVAP Line and Hose Aging (Medium Likelihood): The GLE's extensive EVAP routing along its large body means more lines susceptible to rubber and plastic deterioration. Repair costs $85–$265.
- Charcoal Canister Issues (Low Likelihood): The GLE's larger canister handles more fuel vapor. Saturation or housing cracks after five years of service. Parts $170–$370, labor $140–$280.
Diagnostic Trail
- Scan all control module codes and freeze frame data
- Inspect canister shut-off valve and connector for physical deterioration
- Test valve solenoid resistance and operation
- Test N80 purge valve function
- Inspect all EVAP hoses and lines for aging
- Smoke test if leak codes are present
Repair Costs
- Canister shut-off valve: $225–$460
- Connector repair: $75–$175
- N80 purge valve: $230–$480
- EVAP line repair: $85–$265
- Diagnostic fee: $160–$250
Driving With P0446
P0446 doesn't affect your GLE's performance. The turbocharged engine, 9G-TRONIC automatic, 4MATIC AWD, and all luxury features operate normally.
Emissions Warranty
Mercedes-Benz's basic warranty has expired. The federal emissions warranty covers EVAP for 8 years/80,000 miles through 2028. Contact your dealer to check eligibility.