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Dave Nova
Dave Nova, Buick Technician
Category: Buick
Satisfied Customers: 1808
Experience:  ASE Master Certification. GM World Class Certification
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I have a low-mileage 2005 Buick LeSabre showing a P0446

Customer Question

I have a low-mileage 2005 Buick LeSabre showing a P0446 code. I've also notes that there is carbon showing around the tank filler door. Where should I start to correct the EVAP problem.
Submitted: 10 months ago.
Category: Buick
Expert:  Jared D replied 10 months ago.


The most common cause of a p0446 on this car is a faulty fuel tank pressure sensor.

Check the tank pressure value with the fuel cap and the evaporative vent hose removed from the evaporative canister- you will need a scan tool for this.

Check the fuel tank pressure sensor voltages on the Gray to Black and Dark Green to Black, sensor connected and key on- you will need a multimeter for this.

Should have near 5.0v from the Gray to the Black.

Should have near 1.5v from the Dark Green to the Black.

Expert:  Jared D replied 10 months ago.

Here is how you get to the sensor. No dropping the tank or lift required.