GM Truck Club Forum banner
1 - 3 of 3 Posts

· Registered
22 Posts
Discussion Starter · #1 ·
Hey gang - Any input on some weird codes my 99 Suburban is throwing?

I'm getting:

P1441 - Evaporative Emission System Flow during non-purge
P0446 - PCM has determined that a malfunction exists in the electrical circuit for the vent control in the EVAP control system
P0430 - Catalyst system efficiency for bank 2 is below threshold for the current engine operating conditions

Now, I know that 1441 is the one that gets flagged when the gas cap isn't screwed on tight (for one reason, anyway)...

The other two - are they related? Does the vent control affect the catalyst system efficiency?

Is this a common sequence of events for Suburbans? One of those - "Oh - yeah - you need to replace this, this, and that - they all do that..." kind of things?

Or, is this one of those "take it to the dealer" kind of things?

Or can we tell from this data?

What do you think?

My gut is telling me that I need to look for cracked vacum hoses or loose connections in the vent/gas tank area.. What else?


Tim the Technojunkie

· Premium Member
1,124 Posts
It sounds like your EVAP vent is stuck partially open. See if this information helps you.

"Canister Purge Control Solenoid (CPCS)
CPCS allows fuel vapor to flow from carbon canister to the
engine. Solenoid is normally closed and is pulse-width modulated by
the PCM/VCM to precisely control vapor flow. PCM/VCM controls flow of
fuel vapors based on coolant temperature. At temperatures greater than
113 F (45 C), purge control solenoid is open. Purge control solenoid
is also opened if PCM/VCM detects extreme lean air/fuel mixture ratio

The component appears to be located on the passenger side of the intake manifold with a hose attached to it that has an inline test port a little closer to the front of the engine. Check and make sure this line is not broke or disconnected.

· Registered
22 Posts
Discussion Starter · #3 ·
Well, the line appears to be in good shape.

The connector where it enters the carbon trap doesn't seem to be really tight (I can wiggle it, anyway), but it doesn't pull up or off.

The test valve cover was a bit loose, so I tightened it.

Pulled the battery cable for a minute (to try to reset the codes) and apparently that was either not long enough, or it threw another code right off the bat.

How common is it for the solenoid to fail? It's right were you described it, and the cable appears to be plugged in nice and tight.

Such fun....


Tim the Technojunkie
1 - 3 of 3 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.