Possible causes
– Plugged vapor canister
– Faulty vent solenoid
– Pinched or blocked EVAP hose
– Faulty FTP sensor
– Faulty vent solenoid
– Pinched or blocked EVAP hose
– Faulty FTP sensor
Tech description
Dirt and dust intrusion into the EVAP canister vent hose assembly, resulting in restricted air flow, may cause this condition.
There is a bulletin for the following models:
1999-2007 GMC Sierra (Classic) Models
2007-2008 GMC Sierra Models
GMC Factory Service Bulletin OBDII Code P0446
When is the obd code mean?
The Powertrain Control Module (PCM) sets the P0446 code if the vacuum decay rate is greater than a predetermined value.
Symptoms
– Engine Light ON (or Service Engine Soon Warning Light)
– Possible a noticeable fuel odor caused by the release of fuel vapors
– Possible a noticeable fuel odor caused by the release of fuel vapors
P0446 GMC OBD Code Description