P0446: Evaporative Emission Control System Vent Control Circuit
18 vehicles · 9 makes · $15-$2,500 repair
Most Reported On
P0446 is an OBD-II diagnostic trouble code meaning “Evaporative Emission Control System Vent Control Circuit.” This emissions code points to a problem in the evaporative emission (EVAP) system's vent control circuit, which manages the vent valve that lets the charcoal canister breathe and seals it during leak tests. The EVAP system captures fuel vapors from the tank to keep them out of the atmosphere, and the vent valve must open and close on command for the system to work and self-test. The code sets when the engine computer detects an electrical or performance fault with this vent valve or its circuit. It usually causes only a check engine light with no driveability change, but it does prevent proper EVAP leak monitoring. This code is most commonly reported on 2011-2023 Chrysler 300, 2007-2014 Toyota FJ Cruiser, and 2016-2023 Toyota Tacoma, plus 15 other vehicles, with repair costs ranging from $15 to $2,500.
Common Causes
Typical Repair Cost
Based on 20 documented vehicle-specific issues. Actual cost depends on root cause and vehicle.
Diagnostic Tools
To diagnose P0446, you'll need an OBD-II scanner. Here are our recommendations at every price point.
ANCEL AD310 Classic OBD-II Scanner
by ANCEL
A simple, affordable code reader that reads and clears check engine codes. Great for quick diagnostics on any OBD-II vehicle (1996+).
- Read & clear engine codes
- View freeze frame data
- I/M readiness status
- No batteries or app needed
BlueDriver Pro Bluetooth Scanner
by BlueDriver
Bluetooth OBD-II scanner with a free companion app. Provides enhanced diagnostics, smog readiness, and repair reports sourced from a database of verified fixes.
- Enhanced diagnostics (ABS, SRS, transmission)
- Repair Reports with verified fixes
- Smog check readiness
- Free app (iOS & Android)
LAUNCH CRP123X OBD-II Scanner
by LAUNCH
A professional-grade handheld scanner that reads all four major systems (engine, transmission, ABS, SRS) with live data streaming and graphing.
- Engine, transmission, ABS, SRS diagnostics
- Live data stream & graphing
- AutoVIN for vehicle identification
- Free lifetime updates via Wi-Fi
Autel MaxiCOM MK808S Diagnostic Tool
by Autel
Shop-level diagnostic tablet with bi-directional control, active tests, and full system coverage. Ideal for serious DIYers and small shops.
- All-system diagnostics (25+ modules)
- Bi-directional control & active tests
- Oil reset, EPB, BMS, TPMS, injector coding
- 7-inch touchscreen with Android OS
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Vehicles Affected (18)
EVAP Canister Purge Valve Stuck Open Causing P0496 / Rough Running (3.0L & 3.6L V6)
EVAP Vent Solenoid Clogging With Dust/Water Causing Check Engine Light and Hard Refueling
EVAP Vent Valve and Charcoal Canister Dust Ingestion Causing Check Engine Light and Hard Refueling
A/C Compressor and Evaporator Failure
A/C Musty/Mold Smell
EVAP System Leak-Detection / Vapor Canister Fault (Check Engine Light, Hard Refueling)
EVAP Purge Valve / Charcoal Canister Failure — P0441 / P0455 & Fuel-Pump Click-Off
EVAP Charcoal Canister and Vent Valve Failure Causing Check Engine Light
Evaporative Emissions Leak Faults from Charcoal Canister, Vent Valve, or Filler Neck Corrosion
EVAP System Leak — Charcoal Canister / Vacuum Switching Valve (VSV) Failure (P0440 / P0441 / P0446)
FAQ
What does P0446 mean?
P0446 stands for "Evaporative Emission Control System Vent Control Circuit." This emissions code points to a problem in the evaporative emission (EVAP) system's vent control circuit, which manages the vent valve that lets the charcoal canister breathe and seals it during leak tests. The EVAP system captures fuel vapors from the tank to keep them out of the atmosphere, and the vent valve must open and close on command for the system to work and self-test. The code sets when the engine computer detects an electrical or performance fault with this vent valve or its circuit. It usually causes only a check engine light with no driveability change, but it does prevent proper EVAP leak monitoring.
What are the most common causes of P0446?
The most common causes of P0446 are: Faulty EVAP vent control valve (solenoid), Wiring or connector fault in the vent valve circuit, Vent valve clogged with dirt, debris, or spider webs, Damaged or corroded vent valve connector, Blocked or pinched vent hose or filter, Faulty charcoal canister assembly, Faulty engine control module driver circuit. The specific cause varies by vehicle.
How much does it cost to fix P0446?
Repair costs for P0446 range from $15 to $2,500, depending on the vehicle and root cause.
Which vehicles are affected by P0446?
Au7o has documented P0446 across 18 vehicle models from 9 manufacturers: Chevrolet, Chrysler, Dodge, Ford, Kia, Mazda, Nissan, Pontiac, Toyota.
Sources (12)
- ForumReddit r/ToyotaTacoma thread discussing musty smell in 2016 Tacoma A/C
- ForumMazdas247 Forum - 2006 Mazda5 A/C evaporator leak / dash removal discussion
- ForumSiennaChat — CEL Codes P043E P043F P2401 P2402 P2419
- ForumSiennaChat — EVAP codes P0441, P0455 and pending P0446
- articleGo-Parts — P0455 on 2011-2020 Toyota Sienna: EVAP Large Leak causes and fixes
- Forum3.6L Purge Solenoid replacement — GMC Terrain, Equinox, and SRX Forum
- manufacturerGM Genuine Parts 12690512 Vapor Canister Purge Valve — Chevrolet Parts
- ForumP0496 high purge flow — Ford F150 Forum
- articleFixing EVAP Codes on Ford Expedition, Navigator & F-150 (2005-2019): A Vapor Canister Guide
- ForumCanister Purge Valve on 2015 XLT 3.5L Ecoboost — F150 Ecoboost Forum
- TSBGM bulletin for EVAP canister vent valve replacement and relocation on pickups/SUVs in dusty conditions
- articleFord Explorer P0456: Meaning, Causes, How to Fix - Drivetrain Resource
Content compiled with AI assistance using NHTSA complaints, TSBs, and owner reports. May contain errors. Always verify with your vehicle's service manual.