P0446 - EVAP System Vent Control Circuit
P0446 is a generic powertrain diagnostic trouble code indicating EVAP System Vent Control Circuit. It relates to the Auxiliary Emission Controls system.
DTC Breakdown (SAE J2012)
| System | Powertrain (P) |
| Type | Generic |
| Subsystem | Auxiliary Emission Controls |
| Fault Index | 46 |
| Standard | SAE J2012 / ISO 15031-6 |
What does diagnostic code P0446 mean?
The engine control module logged P0446 after detecting a fault specifically in the control circuit of the EVAP system vent valve solenoid. The PCM detected an incorrect voltage drop when attempting to open or close the vent valve.
Severity Level & Driveability Details
Severity: Low
Low. It does not affect driveability or mechanical function, but will trigger the warning light and lead to inspection failure.
Common Symptoms of P0446
- Check engine light illuminated on the dashboard.
- Difficulty refueling the vehicle (gas pump clicking off repeatedly).
- Fuel vapor smell near the rear of the vehicle.
Typical Causes for P0446
- Defective EVAP canister vent control valve solenoid.
- Clogged or dirty vent valve filter screen restricting air movement.
- Damaged, open, or shorted wiring in the vent valve harness circuit.
- Corroded or loose connector pins at the vent solenoid plug.
Diagnostic and Troubleshooting Steps
Check the vent valve operation using a bi-directional scan tool to command it open and closed. Measure resistance across the solenoid terminal pins with a multimeter (should read 15-30 ohms). Inspect the vent valve filter housing for spider webs or dirt clogs.
Typical Repairs and Fixes
- Replacing the EVAP canister vent control valve solenoid.
- Cleaning or replacing the inline vent valve filter assembly.
- Repairing damaged harness wiring or corroded connector terminals.
Sensor Location & Parts Involved
The EVAP vent control valve is located underneath the vehicle, typically mounted directly to the charcoal canister or fuel tank filler neck assembly.
Clearing Code & Recurrence
Clear the code with a scan tool to reset the monitors and perform a verification drive.
Emissions & Smog Inspection Impact
Allows raw fuel vapors (hydrocarbons) to vent into the atmosphere, causing smog check failures.
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Related Diagnostic Codes
Sources & References
This diagnostic guide is compiled and verified against the following authority sources:
- EPA EVAP Standards
- CARB OBD II regulations
Frequently Asked Questions about P0446
What does the EVAP vent control circuit code P0446 mean?
The engine control module logged P0446 after detecting a fault specifically in the control circuit of the EVAP system vent valve solenoid. The PCM detected an incorrect voltage drop when attempting to open or close the vent valve.
Is it safe to drive with the EVAP vent control circuit code P0446 active?
Yes, an EVAP fault poses no danger to vehicle function.
How much does it cost to repair a EVAP vent control circuit code P0446 fault?
Replacing the vent solenoid averages $150-$250 including parts and labor. The valve itself costs $40-$100.
What are the common causes of the EVAP vent control circuit code P0446?
Trigger conditions for the EVAP vent control circuit code P0446 include: Defective EVAP canister vent control valve solenoid., Clogged or dirty vent valve filter screen restricting air movement., Damaged, open, or shorted wiring in the vent valve harness circuit..
Can I clear the check engine light for EVAP vent control circuit code P0446?
Clear the code with a scan tool to reset the monitors and perform a verification drive.
Will the EVAP vent control circuit code P0446 cause an inspection failure?
Allows raw fuel vapors (hydrocarbons) to vent into the atmosphere, causing smog check failures.