P0446
Fix within 1-2 weeksYour vehicle's evaporative emissions system has a problem with the vent control circuit, meaning it can't properly release or control fuel tank pressure.
Code P0446 means your evaporative emissions system vent control circuit has a problem. Common causes: EVAP vent valve (60%), wiring (25%), clogged charcoal canister (10%). Drivability: Yes, safe to drive. Repair cost: $30-$150 DIY, $130-$450 professional.
Can I Drive With P0446?
Yes, safe to drive
No restrictions on driving, but fix for emissions compliance.
Stop driving immediately if: No need to stop driving unless other symptoms develop.
Symptoms of P0446
- 1Check Engine Light is on
- 2Difficulty fueling your vehicle (fuel pump repeatedly clicks off)
- 3Fuel smell around the vehicle (less common but possible)
Common Causes of P0446
Parts most likely causing this code, ranked by probability
The vent valve is stuck open or closed, or has an electrical fault, preventing the EVAP system from properly venting or sealing.
60% of P0446 cases are fixed by replacing this part
Damaged, corroded, or disconnected wiring to the vent valve prevents the Powertrain Control Module (PCM) from controlling it.
25% of P0446 cases are fixed by repairing the wiring or connector
A clogged or damaged charcoal canister can restrict airflow, causing the vent valve to malfunction or the system to report a circuit issue.
10% of P0446 cases are fixed by replacing the charcoal canister
Cracked, disconnected, or blocked hoses connected to the vent valve or canister can disrupt the system's ability to vent.
5% of P0446 cases are fixed by repairing EVAP hoses or lines
Check These First (Before Buying Parts)
- Ensure your gas cap is fully tightened and not damaged.
- Visually inspect the EVAP vent valve and its electrical connector for any obvious damage or disconnections.
- Look for any cracked, disconnected, or pinched vacuum hoses in the EVAP system.
How to Diagnose P0446
- 1Check your gas cap to ensure it is tight and not damaged.
- 2Visually inspect the EVAP vent valve (often near the charcoal canister) for physical damage or disconnected wires.
- 3Inspect all vacuum hoses and lines connected to the EVAP system for cracks, disconnections, or blockages.
- 4Use a multimeter to test the electrical circuit at the vent valve connector for proper voltage and ground.
- 5Test the resistance of the vent valve solenoid itself to ensure it is within specifications.
- 6If possible, use a scan tool to command the vent valve open and closed while monitoring system pressure.
P0446 on Popular Vehicles
Toyota Camry
2002-2011P0446 is extremely common on these models. The EVAP vent valve (canister vent solenoid) is prone to failure due to dirt and debris contamination, causing it to stick open or closed. It's often located near the charcoal canister under the vehicle.
80% fixed by replacing the EVAP Vent Valve
Honda Accord
2003-2012Similar to Toyota, Honda Accords frequently experience P0446 due to a faulty EVAP vent valve. The valve can fail electrically or mechanically, preventing proper system operation. Inspecting the valve and its connector is crucial.
75% fixed by replacing the EVAP Vent Valve or repairing wiring
Ford F-150
2004-2014Ford F-150s can also trigger P0446, often due to a failing EVAP vent valve or a clogged charcoal canister. Overfilling the fuel tank can lead to charcoal canister saturation and subsequent vent valve issues.
70% fixed by replacing the EVAP Vent Valve or Charcoal Canister
Frequently Asked Questions
What does P0446 mean?
P0446 indicates a malfunction in the evaporative emission control system's vent control circuit. This means the system cannot properly manage the pressure and vacuum within your fuel tank.
Can I drive with P0446?
Yes, you can drive safely with a P0446 code. This code primarily affects your vehicle's emissions system and will not cause immediate damage or leave you stranded. However, you must fix it to pass emissions inspections.
Will P0446 clear itself?
No, P0446 will not clear itself. The Powertrain Control Module (PCM) needs to see the vent control circuit functioning correctly over several drive cycles before the code will clear. You will likely need to replace a faulty component and then clear the code with a scan tool.
How do I fix P0446 myself?
Start by checking your gas cap and inspecting all EVAP hoses for damage. The most common fix is replacing the EVAP vent valve (canister vent solenoid), which is often located near the charcoal canister under the vehicle. You will need basic hand tools and possibly a multimeter to test the circuit.
How much does it cost to fix P0446?
The cost to fix P0446 yourself is typically $30-$150 for a new EVAP vent valve. If you take it to a professional shop, expect to pay $130-$450, which includes parts and labor.
P0446 keeps coming back - why?
If P0446 keeps returning, it means the underlying issue was not fully resolved. This often happens if you replaced the vent valve but the problem was actually in the wiring, a clogged charcoal canister, or another part of the EVAP system that was overlooked. A thorough diagnosis is necessary.
Will P0446 fail emissions/smog test?
Yes, P0446 will cause your vehicle to fail an emissions or smog test. The Check Engine Light being on due to this code is an automatic failure in states with such inspections.
What's the difference between P0446 and P0440?
P0446 specifically points to a malfunction in the EVAP system's vent control circuit. P0440 is a more general code indicating a 'General Evaporative Emission Control System Malfunction,' meaning there's a problem somewhere in the system, but it doesn't pinpoint a specific component like P0446 does.
P0446 on Toyota Camry?
P0446 is a very common code on Toyota Camry models, especially those from 2002-2011. The most frequent cause is a faulty EVAP vent valve (canister vent solenoid), which often gets contaminated with dirt or debris, causing it to stick. Replacing this valve typically resolves the issue.
Questions to Ask Your Mechanic
Did you test the EVAP vent valve's electrical circuit and resistance?
Good answer: Yes, I confirmed proper voltage and ground at the connector, and the valve's resistance is out of specification, indicating an internal fault.
Did you check for any blockages in the charcoal canister or vent lines?
Good answer: Yes, I visually inspected the canister and blew air through the vent lines to ensure they are clear and not restricted.
Repair Cost Estimate
DIY Repair
Parts only
$30-$150
Shop Repair
Parts + labor
$130-$450
Save $100-$300 by doing it yourself
Difficulty
beginner
Time
0.5-1.5 hours
Beginner-friendly - Replacing the EVAP vent valve typically requires basic hand tools and is often accessible without specialized equipment.
Cost of Waiting
Ignoring P0446 will cause your vehicle to fail emissions inspections. While it won't damage your engine, prolonged issues can lead to difficulty fueling your vehicle and potentially damage other EVAP components if the system remains unable to vent properly.
While You're In There...
While not directly related to P0446, the purge valve is another common EVAP component that can fail and is often easily accessible when working on the vent valve or canister.
If the vent valve is integrated with or very close to the charcoal canister, or if the canister is suspected of being clogged, replacing both at the same time prevents repeat labor.
Tools You'll Need
- Basic hand tools (sockets, wrenches)
- Multimeter (for electrical testing)
- Scan tool (to clear code)
P0446 is a common emissions code that does not affect your vehicle's drivability. The repair is usually straightforward and inexpensive, getting your vehicle back to normal quickly.
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Your Next Steps
Step 1: Check your gas cap and visually inspect all EVAP hoses and the vent valve's wiring for any obvious issues.
Step 2: If no visual issues are found, use a multimeter to test the electrical circuit and resistance of the EVAP vent valve. If it fails, replace the valve.
Step 3: If the vent valve tests good, consider a smoke test of the EVAP system to find any leaks, or inspect the charcoal canister for blockages. Parts you'll likely need: EVAP vent valve.