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Ask GM Tech (Cam) Your Own Question
GM Tech (Cam)
GM Tech (Cam), Pontiac Technician
Category: Pontiac
Satisfied Customers: 29588
Experience:  GM Grand Master Technician 2007. 14 years experience.
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P0446 CODE

Customer Question

P0446 CODE
Submitted: 2 years ago.
Category: Pontiac
Expert:  GM Tech (Cam) replied 2 years ago.

Hi there, I am Cam. Can I get your first name please? With that code, its not a code set by an open circuit, its a code set when the computer does not see what its expecting. Normally with that code we see the canister is plugged with dirt and the valve is not sealing causing a leak. DO you live or drive on a lot of dirt?

Customer: replied 2 years ago.
the car has been sitting for about a year and not really dirty . it is rusty though. My understanding is it was a sytem vent control circuit which I thought would be the computer monitoring the coil circiot of the vent valve
Customer: replied 2 years ago.
I am referring to code P0446
Expert:  GM Tech (Cam) replied 2 years ago.

The computer controls the ground side of the vent circuit, so power is applied to the pink wire from the fuse block, and when the ECM wants it open, it grounds it. If the circuit was an issue, Code P0449 would be set. P0446 is performance only. Its not electrical in nature.

Customer: replied 2 years ago.
good to know. Is there anything else I can do to clear this code from coming back
Expert:  GM Tech (Cam) replied 2 years ago.

Once the code is fixed you will need to drive it to allow the system monitors to reset and run the tests to pass this code. The light should remain out if the code is not set and it does not need to fail once to set the code. IT must fail 2 times in a row for the light to come back on.

Customer: replied 2 years ago.
I have a scan tool and reset all the codes last night. I did not drive the car. I checked it this morning the check engine light was on and the scan tool showed P0446. So I checked the solenoid and put the car back together and reset the computer again. Is there something else I should be checking?
Expert:  GM Tech (Cam) replied 2 years ago.

No, it should be ok then, but you can try s different reset. Take the battery cables off the battery, hold the ends together for 10 seconds then attach them to the battery and see what happens. This will reset the whole vehicle.

Customer: replied 2 years ago.
You mentioned dirt in the charcoal can, should I take it out and give it a blow test to make sure its not full of crud. I was going to take it for a run to get the drive cycles up. I just dont want to burn gas and waste time if the same code is going to come back.
Expert:  GM Tech (Cam) replied 2 years ago.

The way to tell is remove the line from the canister to the valve and see if that line has ANY dust or dirt. If it does, remove the canister and blow air into the 2 smaller points and push it out the large port that goes to the valve. and pulse the air while tapping on the housing of the canister with the handle of a screwdriver. IF no dust comes out then its not likely full of dirt.

Customer: replied 2 years ago.
like cleaning the old shop vac filter
Customer: replied 2 years ago.
codes are clear on the computer and I will check the can
Expert:  GM Tech (Cam) replied 2 years ago.

Right, that is correct.

Customer: replied 2 years ago.
can was clean but I cleaned it anyway. Can I do anything else?
Expert:  GM Tech (Cam) replied 2 years ago.

Drive it and see what happens next.

Customer: replied 2 years ago.
will do thanks
Expert:  GM Tech (Cam) replied 2 years ago.

My pleasure. Let me know how it goes.