EVAP P0446

[TomO]

Check engine light came on this morning. Code P0446 - EVAP. Online I’m seeing mixed starting points on this 1. What do you all suggest? First time driving it on a cool morning in Indiana - guessing this Texas truck didn’t know what to do with this dense Indiana air!

2003 suburban 174k.

 

[99Sierra2500]

P0446

SYSTEM DESCRIPTION
This DTC tests the evaporative emission (EVAP) system for a restricted or blocked EVAP vent path. The control module commands the EVAP canister purge solenoid Open and the EVAP canister vent solenoid Closed. This allows vacuum to be applied to the EVAP system. Once a calibrated vacuum level has been reached, the control module commands the EVAP canister purge solenoid Closed and the EVAP canister vent solenoid Open. The control module monitors the fuel tank pressure (FTP) sensor for a decrease in vacuum. If the vacuum does not decrease to near 0 inches H2O in a calibrated time, this DTC sets.

 

[TomO]

Some good info here - both in the video and in the comments.

 

[ORVietVet]

Good videos. There have been literally millions of the purge valves sold because of it's location.

 

[TomO]

Plan on doing new purge valve, vent valve & gas cap. I’ll probably blow out the lines and clean the charcoal canister as well. Is there a special tool to disconnect the hoses?

 

[TomO]

If that doesn’t do it it’s probably the tank pressure sensor.

 

[TomO]

Decided to dig in a little more - I might be changing my plans.

Looked at the scan from O’Reillys again - it actually suggested starting with the tank pressure sensor.

FYI - the guy in this video is slightly unhinged!!