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Check engine code p0446

Posted By: boocat

Check engine code p0446 - 10/18/17 07:31 PM

Any Chevy mechanics here? Wife's 06 hhr throwing a p0446. Something about the evaporate vapor system.. I replaced the evap solenoid cleared the code,, light is back.. Any ideas?
Posted By: TXMako2201

Re: Check engine code p0446 - 10/19/17 02:15 PM

did you replace the evap canister? If so, did you replace the filter also? both should be done at the same time.
Posted By: MarcM64

Re: Check engine code p0446 - 10/20/17 01:15 AM

Probably need to check the fuel tank pressure sensor... Like above said.. The canister may need to be replaced... Which solenoid did you replace?
Posted By: boocat

Re: Check engine code p0446 - 10/20/17 10:10 AM

i replaced the one under the hood.
Posted By: spankyttx

Re: Check engine code p0446 - 10/20/17 12:50 PM

under the hood? i thought all this vapor can stuff was under the vehicle behind the rear drag axle, i could be wrong but that solenoid and pressure sensor should be with or around the vapor canister, have you checked or replaced the fuel cap?
Posted By: redchevy

Re: Check engine code p0446 - 10/20/17 02:22 PM

Been a few years since I replaced it, but there is one on top of the motor also. I replaced it on my mom's Tahoe when I put a new oil pressure sensor in, it cured the check engine light for a while, but it has since reared its head again and suspect one of the other parts of the system.
Posted By: boocat

Re: Check engine code p0446 - 10/20/17 02:37 PM

Will take a closer look at the gas cap.. Yes,, the one under the hood.. Will try and get under that little car to check the other.. If I can't work under there, its off to the dealer with some ky.
Posted By: Todd™

Re: Check engine code p0446 - 10/20/17 09:13 PM

Purge valve is under the hood and vent valve is by the canister. I would not be surprised if it's the fuel tank pressure sensor as stated. Tank has to be dropped for that.
Posted By: patriot07

Re: Check engine code p0446 - 10/23/17 02:00 AM

Did you try cleaning the throttle body? Does it run good?
Posted By: boocat

Re: Check engine code p0446 - 10/23/17 01:12 PM

runs perfect
Posted By: spankyttx

Re: Check engine code p0446 - 10/23/17 02:48 PM

how's your progress on this boocat?
Posted By: Todd™

Re: Check engine code p0446 - 10/23/17 04:05 PM

For a little info this code is related to a test for a blocked or restricted vent of the EVAP system. During the test the purge valve (underhood) is opened and the vent valve (by canister) is closed. This allows vacuum to be applied to the fuel tank. The ECM then closes the purge valve and opens the vent valve to watch for a vacuum drop in the tank via the fuel tank pressure sensor. If it does not go to 0 in a predetermined amount of time code p0446 will set.

You've got a possibility of a clogged canister, clogged vent tube, bad vent valve stuck shut, or bad fuel pressure sensor. More times than a clogged system or bad valve we see bad fuel tank pressure sensors. Bad thing for you is we use "THE SUPER DUPER CAR FIXING COMPUTER" to apply vacuum, command the valves for testing, and monitor the fuel pressure sensor data to determine what has failed.

If you still would like to guess before having to take it to a shop don't waste time on throttle bodies and gas caps for code p0446. You've got a clogged system, bad vent valve, or bad pressure sensor.
Posted By: boocat

Re: Check engine code p0446 - 10/23/17 06:08 PM

yeah, I think its off to dealer. She wants to sell it anyway..06 hhr lt with 14,000. miles... She don't drive much.
Posted By: boocat

Re: Check engine code p0446 - 10/24/17 10:45 PM

yep, tank pressure sensor, $550.
Posted By: Todd™

Re: Check engine code p0446 - 10/25/17 01:45 PM

That's about right on price. Every shop has different labor rates per hour. Might be a tad high so I hope you gave it to them with a full tank so they had to work for it.
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