[mdekom]

I have a 2008 Outlook and I’m getting codes P0449 and P0449P. There’s very little info on the web about code P0449P. Evidently this problem is with one of two solenoids or a vapor canister. Any speculation as to which is the most likely? Any help, of course, I’m grateful.

 

[h2oskierc]

I see zero mention of a "p0449p" code in the service manual. I don't think such a code exists (The P at the front indicates it is an OBD2 Powertrain Code, then the four numbers give a specific code).

P0449 is defined as: "Evaporative Emission (EVAP) Vent Solenoid Control Circuit"

Here is the relevant info from the service manual

Circuit/System Description

An ignition voltage is supplied directly to the evaporative emission (EVAP) canister purge solenoid valve. The engine control module (ECM) grounds the EVAP canister purge solenoid valve control circuit through an internal switch called a driver. The ECM monitors the status of the driver. The EVAP canister purge solenoid valve is pulse width modulated (PWM). A scan tool will display the amount of ON time as a percentage.

Battery voltage is supplied to the EVAP canister vent solenoid valve. The ECM grounds the EVAP canister vent solenoid valve control circuit through an internal switch called a driver. The ECM monitors the status of the driver. A scan tool will display the commanded state of the EVAP canister vent solenoid valve as ON or OFF.

Conditions for Running the DTC

The ignition is ON.
The system voltage is between 6-18 volts.
DTC P0443 and P0449 run continuously when the above conditions are met.
Conditions for Setting the DTC

The control module detects that the commanded state of the driver and the actual state of the control circuit do not match, for a minimum of 12 seconds.

Action Taken When the DTC Sets

DTCs P0443 and P0449 are Type B DTCs.

Conditions for Clearing the MIL/DTC

DTCs P0443 and P0449 are Type B DTCs.

Circuit/System Verification

P0443

With the ignition ON, and the engine OFF, you should hear a clicking sound when the EVAP canister purge solenoid valve is commanded to 50 percent with a scan tool. The clicking sound should stop when the EVAP canister purge solenoid valve is commanded to 0 percent. The rate at which the valve cycles should increase when the commanded state is increased, and decrease when the commanded state is decreased.

P0449
With the ignition ON and the engine OFF, command the EVAP vent solenoid ON and OFF with a scan tool.
Listen for a click when the valve operates. Verify that both the ON, and the OFF states are commanded.
Circuit/System Testing

Ignition OFF, disconnect the harness connector at the EVAP canister purge or vent solenoid valve.
Ignition ON, verify that a test lamp illuminates between the B+ or ignition circuit terminal A and ground.
If the test lamp does not illuminate, test the B+ or ignition circuit for a short to ground or an open/high resistance. If the circuit tests normal and the voltage supply circuit fuse is open, test or replace the appropriate solenoid valve.
Connect a test lamp between the control circuit terminal B and the B+ or ignition circuit terminal A.
Energize the solenoid with a scan tool. Command the EVAP canister purge solenoid valve to 50 percent with a scan tool, or the EVAP canister vent solenoid valve ON and OFF. The test lamp should respond to the command.
If the test lamp is always ON, test the control circuit for a short to ground. If the circuit tests normal, replace the control module.
If the test lamp is always OFF, test the control circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the control module.
If all circuits test normal, replace the appropriate solenoid valve.

If it is the evaporative purge valve solenoid, it is a cheap, easy fix. Any symptoms that you have noticed? Car not starting after refueling?

 

[mdekom]

Many thanks for your expertise.

The scanner shows two codes as described, including one with the "P" fore and aft. The google search of the code shows up in other GM models. the vehicle does not have any starting problem, but once it went into Limp Mode. for obvious reasons I am loathe to drive it any distance.

 

[no1pony]

Many thanks for your expertise.

The scanner shows two codes as described, including one with the "P" fore and aft. The google search of the code shows up in other GM models. the vehicle does not have any starting problem, but once it went into Limp Mode. for obvious reasons I am loathe to drive it any distance.

Sorry to revive old Thread. I am chasing this issue also. The P you are referring to means Pending. I am also trying to figure out where to go with this issue. I am also getting traction control lights. I have read some info that suggested the MAF. I replaced that first with no change. What is odd when I clear the code It comes back right away.

 

[mdekom]

Revive away. You need two parts:
Vapor Canister Purge Valve-Evap Emis Hose ACDelco GM Original Equipment 20907779
and
ACDelco 19257603 Evaporative Emission Canister Valve Solenoid Jumper Wiring

Total cost is about $100 on ebay. Everything will tell you that the wiring section does not fit your car. It does. The canister does not fit like OEM, so get the 2nd part. This advice is from finding other threads which said the same thing, as well as having done it.

You have to lower the gas tank to do it, which isn't a big deal if you have a good hydraulic jack and and stands. It took about 40 minutes to do; life will be easier the less gas in the tank.

good hunting.