Easy one-page printout for the garage or repair shop
This summary uses the existing diagnostic information shown in full below.
This code means that the car's system that controls gas fumes isn't working right. It's like when a cap on a soda bottle doesn't close properly, letting the fizz escape.
The P0446 code is triggered when the Engine Control Module (ECM) detects a malfunction in the evaporative emission control system's vent control circuit.
The EVAP system prevents fuel vapors from escaping into the atmosphere by trapping them in a charcoal canister and then purging them into the engine to be burned. The vent control circuit is responsible for opening and closing the vent valve, allowing fresh air into the system. A malfunction in this circuit can lead to improper venting and purging of fuel vapors.
• Check Engine Light is on
• Fuel odor in or around the vehicle
• Failed emissions test
• Faulty vent control valve
• Damaged or disconnected vent control wiring
• Blocked or restricted vent control lines
EVAP: Evaporative Emission Control System
ECM: Engine Control Module
• Inspect the vent control valve for damage or blockage.
• Check the wiring and connectors for the vent control circuit.
• Test the operation of the vent control valve using a scan tool.
• Replace the vent control valve if faulty.
• Repair or replace damaged wiring or connectors in the vent control circuit.
• Clear the EVAP system of any blockages.
• OBD-II scan tool
• Multimeter
• Vacuum pump
$150 - $400
Moderate
• Toyota Camry
• Honda Accord
• Ford F-150
• Regularly inspect and maintain the EVAP system.
• Ensure gas cap is properly sealed.
• Avoid overfilling the fuel tank.
Emission Control System Issue
• Have the vehicle inspected by a professional if you smell fuel.
• Do not ignore the Check Engine Light as it may lead to more serious issues.
• Consider regular maintenance checks to prevent future occurrences.
Repairs may be covered under emissions warranty if the vehicle is still under coverage.
P0446 has been a common code since the introduction of OBD-II systems, often related to vent valve issues.
Moderate – While not immediately dangerous, it can lead to increased emissions and potential fuel economy issues.
Driving with a malfunctioning EVAP system may result in failing emissions tests and increased pollution.
• Vehicle at operating temperature
• Fuel tank between 1/4 and 3/4 full
The vent control valve is typically located near the charcoal canister, which is often found near the rear of the vehicle, close to the fuel tank.
Q: Can I drive with a P0446 code?
A: Yes, but it's not recommended for long periods as it can affect emissions and fuel efficiency.
Q: Will P0446 cause my car to fail an emissions test?
A: Yes, a P0446 code can cause your vehicle to fail an emissions test.
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Universal · Digital multimeter
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Useful when diagnosis points toward damaged wiring, corroded terminals, or connector repairs.
Useful if diagnosis points toward damaged connectors, wiring, or terminal repairs.
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Fitment Required · Vehicle-fitment part
Relevant when EVAP diagnosis points toward purge-flow or purge-control faults.
EVAP diagnosis often includes purge-flow and valve-control faults.
Confirm the failed valve and exact fitment before buying parts.
View options on AmazonThese parts may be related to this fault category, but a code by itself does not confirm exact fitment or guarantee that replacing a part will solve the problem.