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P0446 Buick Code - Evaporative Emission Vent System Performance

- Code Popularity: 39,090 Views
- Repair Importance Level: 1/3
- Repair Difficulty Level: 3/3
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What are the Possible Causes of the DTC P0446 Buick?

NOTE: The causes shown may not be a complete list of all potential problems, and it is possible that there may be other causes.
  • Plugged vapor canister
  • Pinched or blocked EVAP hose
  • Faulty Evaporative Emission Vent Solenoid Valve
  • Evaporative Emission Vent Solenoid Valve harness is open or shorted
  • Evaporative Emission Vent Solenoid Valve circuit poor electrical connection
  • Faulty Fuel Tank Pressure (FTP) sensor
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How to Fix the DTC P0446 Buick?

Review the 'Possible Causes' mentioned above and visually examine the corresponding wiring harness and connectors. Ensure to check for any damaged components and inspect the connector pins for signs of being broken, bent, pushed out, or corroded.

Code Tech Notes

Dirt and dust intrusion into the EVAP canister vent hose assembly, resulting in restricted air flow, may cause this condition.

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What is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the P0446 Buick code, it typically requires 1.0 hour of labor. The specific diagnosis time and labor rates at auto repair shops can differ based on factors such as the location, make and model of the vehicle, and even the engine type. It is common for most auto repair shops to charge between $75 and $150 per hour.

What are Code Possible Symptoms?

  • Engine Light ON (or Service Engine Soon Warning Light)
  • A noticeable fuel odor may result from fuel vapor release

Code P0446 Buick Description

This Diagnostic Trouble Code (DTC) tests the Evaporative Emission (EVAP) system for a restricted or blocked EVAP vent path that would cause excess amounts of vacuum to be developed in the EVAP system. The Engine Control Module (ECM) commands the EVAP purge solenoid valve Open and the EVAP vent solenoid valve Closed. This allows vacuum to be applied to the EVAP system. Once a calibrated vacuum level has been reached, the ECM commands the EVAP purge solenoid valve Closed and the EVAP vent solenoid valve Open. The ECM monitors the Fuel Tank Pressure (FTP) sensor for a decrease in vacuum. If the vacuum does not decrease to near 0 in H2O in a calibrated time, this DTC sets.
OBDII Code P0446 Buick - Evaporative Emission Vent System Performance - AutoCodes.com
P0446 Buick Code - Evaporative Emission Vent System Performance

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