Investigating P0446 on Your 2020 Lexus IS
A P0446 code on your 2020 Lexus IS points to an EVAP vent control circuit malfunction. The IS uses the GA-N platform with either the 2.0L turbocharged four-cylinder (IS 300 RWD) or the 3.5L V6 (IS 300 AWD/IS 350). Lexus uses a canister close valve (CCV) for EVAP vent control, built on Toyota's proven architecture.
The basic warranty (4yr/50k) has likely expired, but the powertrain warranty (6yr/70k) may still be active through 2026. The federal emissions warranty (8yr/80k) covers EVAP components through 2028.
Clues and Symptoms
- Check engine light with P0446 stored
- Fuel fill difficulty
- EVAP readiness monitor incomplete
- Possible fuel odor
Top Suspects
- Canister Close Valve (CCV) Failure (High Likelihood): The CCV degrades after years of operation. Replacement costs $140–$260.
- Purge VSV Malfunction (High Likelihood): The Vacuum Switching Valve sticks open or closed. Replacement runs $120–$220.
- CCV Wiring or Connector Corrosion (Medium Likelihood): Five years of exposure can corrode connectors. Repair costs $80–$170.
- Charcoal Canister Saturation (Medium Likelihood): Age-related canister degradation. Replacement runs $200–$370.
- Gas Cap Seal (Low Likelihood): Worn seal. Replacement is $15–$30.
How to Investigate
Scan for all codes. A Techstream scan at a Lexus dealer provides CCV and purge VSV commanded testing. For DIY, check the gas cap seal first, then inspect the CCV connector. Toyota/Lexus EVAP systems are reliable—a P0446 usually indicates a definitive component failure.
Warranty and Cost
The basic warranty has likely expired, but check if the powertrain warranty (6yr/70k) is still active through 2026. The federal emissions warranty (8yr/80k) covers EVAP through 2028. Out of warranty: $120–$370.
Safe to Drive?
Yes. P0446 doesn't affect your IS's engine performance, sport-tuned handling, transmission, or any driving dynamics.