Illustration of OBD codes in a car

Error Code P0446

Low Issue
DTC Code P0446 indicates an issue with the Evaporative Emission (EVAP) Vent System Performance, where a restricted or blocked EVAP vent path causes excessive vacuum in the system. The Engine Control Module (ECM) monitors the Fuel Tank Pressure (FTP) sensor to ensure proper vacuum levels are maintained.

What symptoms indicate Error Code P0446?

  • Engine Light ON: The check engine light or service engine soon warning light illuminates, indicating an issue with the evaporative emission vent system.
  • Fuel Odor: A noticeable fuel odor may be present due to the release of fuel vapors, which can be linked to a malfunction in the evaporative emission vent system.

What causes OBD code Error Code P0446?

  • The vapor canister may be plugged, preventing proper venting of fuel vapors.
  • An EVAP hose could be pinched or blocked, disrupting the flow of vapors.
  • The Evaporative Emission Vent Solenoid Valve might be faulty, affecting the system's performance.
  • The harness for the Evaporative Emission Vent Solenoid Valve could be open or shorted, leading to electrical issues.
  • Poor electrical connections in the Evaporative Emission Vent Solenoid Valve circuit can cause intermittent failures.
  • A malfunctioning Fuel Tank Pressure (FTP) sensor may provide incorrect pressure readings, triggering the code.

How to fix OBD code Error Code P0446?

  • Verify DTC Code: Confirm the presence of DTC P0446 using an OBD-II scanner. Check for any additional codes that may be related to the evaporative emission system.
  • Inspect EVAP Vent Valve: Locate the EVAP vent valve and inspect it for any signs of damage, blockage, or disconnection. Ensure the valve is not stuck in the closed position.
  • Check Vent Valve Solenoid: Test the vent valve solenoid for proper operation. Use a multimeter to check for continuity and ensure the solenoid is receiving the correct voltage.
  • Examine EVAP Hoses: Inspect all EVAP system hoses for cracks, leaks, or disconnections. Pay special attention to the hoses connected to the vent valve.
  • Test EVAP System Pressure: Perform a smoke test to check for leaks in the EVAP system. This will help identify any leaks that may be causing the vent system performance issue.
  • Review Related Codes: Consider related codes such as P0440, P0441, and others listed. These may provide additional insights into the root cause of the issue.
  • Check Electrical Connections: Inspect the electrical connections to the vent valve and related components. Ensure all connectors are secure and free of corrosion.
  • Perform Functional Test: Use a scan tool to perform an active test of the EVAP vent valve to ensure it opens and closes as commanded by the ECM.

Similar OBD Codes

P0440

Evaporative Emission Control System Malfunction

P0441

Evaporative Emission Control System Purge Flow Issue

P0443

Evaporative Emission Control System Purge Valve Circuit Malfunction

P0449

Evaporative Emission Vent Solenoid Valve Circuit Issue

P0497

Evaporative Emission System Low Purge Flow Detected

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