P0446 code

2000 CADILLAC SEVILLE
90,000 MILES • 4.6L • V8 • 2WD • AUTOMATIC
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KE7VMY
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Where should I look first?
Feb 26, 2019 at 8:32 PM
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SCGRANTURISMO
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Hello,

This could be a plugged or full charcoal canister in your Evaporative Emissions (EVAP). This system is part of your vehicle's emissions control system and works by collecting and then purging fuel vapors into the combustion process via the throttle body. Fuel vapors are collected and stored in a charcoal canister. When this canister fails the Power-train Control Module (PCM) AKA, "computer" will set Direct Trouble Code (DTC) P0446.
I have included in the diagrams below a step by step troubleshooting guide for this DTC, Please go through it and get back to us with what you find out.

Thanks,
Alex
2CarPros
Feb 26, 2019 at 9:29 PM
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JIS001
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I would recommend you get an EVAP smoker. Disconnect the purge valve hose to the tank and smoke it. If smoke comes out the vent then your fuel tank pressure sensor is bad. If no smoke comes out then check for a stuck closed vent valve or a spider nest build up at the vent tube.
Feb 26, 2019 at 10:52 PM
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KE7VMY
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The vent solenoid was sticking and I applied 12 volts AC to it to cycle it and it cleared it up for now so I can get the emission test done a then after that I will get a new solenoid. My tabs run out on the 28th so I was in a sweat to get the problem fixed. Many thanks for all your help, you guys are great.

Bill T.
Feb 27, 2019 at 2:21 PM
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JIS001
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Thank you for using 2CarPros. Glad it worked out for now so you can get your emissions test done.
Feb 27, 2019 at 9:38 PM