Po449 code
05-19-2010, 08:02 PM
#2
There is a TSB about this code, you need to replace the vent solenoid and run a hose off of it up the transmission tunnel to keep dirt and debris from getting in the evap vent solenoid and clogging it up. If you went to the dealer and asked for the kit for the evap vent solenoid they'll probably know what you're talking about...or type P0449 in the search box of the GM section and you'll find a few threads about it, and maybe even part numbers and the TSB
05-19-2010, 10:45 PM
#4
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2005 what? Only tsb I show for is for 07-09. But Vehicels (mainly chevy trucks) with code po449 evap vent problem I have found most of the time the connecter to the valve losses ground from the computer. The problem is at the pigtail, the wire turns green and looses connection 3or4 inches from connector. Use pigtail #pt250 to replace the bad connection. Also be sure to use updated valve and relocate the filter.
05-19-2010, 10:57 PM
#5
I'm assuming 2005 Silverado, especially since he said P0449 which sticks out in my head...here, this may help...
Bulletin No.: 02-06-04-037E
Date: April 09, 2009
Subject:
DTC P0446 (Restricted/Blocked EVAP Vent Path) Set, Check Engine Light On (Replace Evaporative Emission (EVAP) Vent Valve Solenoid Assembly and Add/Relocate Filter Box Using Service Kit)
Models:
1999-2007 Chevrolet Silverado (Classic) Models
1999-2007 GMC Sierra (Classic) Models
2007-2009 Chevrolet Silverado Models (Excluding Hybrid)
2007-2009 GMC Sierra Models (Excluding Hybrid)
Supercede:
This bulletin is being revised to add 2009 to the models. Please discard Corporate Bulletin Number 02-06-04-037D (Section 06 - Engine/Propulsion System).
Condition
Some customers whose vehicles are operated in dusty type environments, such as farming or mining off-road type applications, may comment about the illumination of the check engine light, with a DTC of P0446 (Restricted/Blocked EVAP Vent Path) being set.
Cause
Dirt and dust intrusion into the EVAP canister vent hose assembly, resulting in restricted air flow, may cause this condition.
Correction (1999-2007 Classic/Old Style Models)
After following the published SI diagnostics for P0446 and determining that the EVAP canister vent valve is the cause of the MIL light, replace the existing EVAP canister vent valve assembly with a new assembly. This new assembly is a sealed unit that is designed to be vented through a remote filter box. To ensure correct installation, follow the procedures below.
1999-2003 Model Year (Use Service Kit P/N 19152345)
1. Raise the vehicle. Suitably support the vehicle.
2. Disconnect the EVAP canister vent valve electrical connector, if equipped.
3. Disengage the two vent valve pipe clips securing the pipe to the underbody. Remove the clips from the underbody and discard.
4. Disconnect the vent valve pipe at the EVAP canister.
5. Remove and retain the EVAP canister vent valve bracket mounting bolt.
6. Remove the complete EVAP canister vent valve assembly with bracket attached and discard.
Important
The new canister vent valve will be installed in a new location, outside of the frame.
7. Position and secure the new valve assembly to the frame bracket on the outside of the frame using the existing hole and mounting bolt.
Tighten
Tighten the bracket mounting bolt to 12 Nm (106 lb in).
8. Connect the vent valve pipe to the EVAP canister.
9. Install the two vent valve pipe clips into the existing underbody holes.
10. Connect the EVAP canister vent valve electrical connector, if equipped.
11. Attach bulk 5/8" heater hose to the vent valve port and secure using a clamp. Run a length as needed along the frame rail routing to the area above the transmission.
12. Cut the hose to determined length and install the supplied filter box. Secure using a clamp.
13. Remove the transmission support and lower the transmission assembly as necessary to allow for access to the new filter box location.
14. Secure the filter box to the transmission vent hose just forward of the hose tee-section using a tie strap. DO NOT pinch or restrict the transmission vent hose. The filter box opening should be pointing downward.
15. Raise the transmission and reinstall the transmission support.
16. Tie strap the hose as needed along the frame rail in order to keep the hose away from pinch-points and heat sources.
17. Lower the vehicle.
2004-2007 Model Year (Use Service Kit P/N 19152349)
1. Raise the vehicle. Suitably support the vehicle.
2. Disconnect the EVAP canister vent valve electrical connector.
3. Disconnect the canister pipe from the vent valve.
4. Push in the retainer and remove the existing canister vent valve from the fuel tank clip or mounting bracket. Discard the old valve.
5. Cut back the existing canister pipe approximately 51 mm (2 in) to remove the quick connect end.
6. Install the new canister vent valve to the fuel tank clip or mounting bracket.
7. Cut bulk 5/8" heater hose to a length of approximately 76 mm (3 in). Install the hose between the vent valve and the canister pipe and secure using clamps.
8. Attach bulk 5/8" heater hose to the vent valve port and secure using a clamp. Run a length as needed along the frame rail routing to the area above the transmission.
9. Cut the hose to determined length and install the supplied filter box. Secure using a clamp.
10. Remove the transmission support and lower the transmission assembly as necessary to allow for access to the new filter box location.
11. Secure the filter box to the transmission vent hose just forward of the hose tee-section using a tie strap. DO NOT pinch or restrict the transmission vent hose. The filter box opening should be pointing downward.
12. Raise the transmission and reinstall the transmission support.
13. Connect the EVAP canister vent valve electrical connector.
14. Tie strap the hose as needed along the frame rail in order to keep the hose away from pinch-points and heat sources.
15. Lower the vehicle.
Correction (2007-2009 New Style Models)
After following the published SI diagnostics for P0446 and determining that the EVAP canister vent valve is the cause of the MIL light, replace the EVAP canister vent valve assembly and relocate the remote filter box. To ensure correct installation, follow the procedures below.
Use Service Kit P/N 19152349
1. Raise the vehicle. Suitably support the vehicle.
2. Disconnect the EVAP canister vent valve electrical connector.
3. Disconnect the vent valve pipe quick connect from the canister.
4. Either cut the existing valve vent pipe and leave the remaining section of pipe in the vehicle or remove along with the valve.
5. Push in the retainer and remove the existing canister vent valve from the fuel tank clip or mounting bracket.
6. Cut back the existing canister pipe approximately 51 mm (2 in) and retain the pipe for use with new valve.
7. Connect the canister pipe quick connect to the canister.
8. Install the new canister vent valve to the fuel tank clip or mounting bracket.
9. Cut bulk 5/8" heater hose to a length of approximately 76 mm (3 in). Install the hose between the vent valve and the canister pipe and secure using clamps.
10. Attach bulk 5/8" heater hose to the vent valve port and secure using a clamp. Run a length as needed along the frame rail routing to the passenger side area above the transmission.
11. Cut the hose to determined length and install the supplied filter box. Secure using a clamp.
12. Remove the transmission heat shield, if necessary.
13. Remove the transmission support and lower the transmission assembly as necessary to allow for access to the new filter box location.
14. Secure the filter box to the transmission vent hose just forward of the hose tee-section using a tie strap. DO NOT pinch or restrict the transmission vent hose. The filter box opening should be pointing downward.
15. Raise the transmission and reinstall the transmission support.
16. Reinstall the transmission heat shield.
17. Connect the EVAP canister vent valve electrical connector.
18. Tie strap the hose as needed along the frame rail in order to keep the hose away from pinch-points and heat sources.
19. Lower the vehicle.
Bulletin No.: 02-06-04-037E
Date: April 09, 2009
Subject:
DTC P0446 (Restricted/Blocked EVAP Vent Path) Set, Check Engine Light On (Replace Evaporative Emission (EVAP) Vent Valve Solenoid Assembly and Add/Relocate Filter Box Using Service Kit)
Models:
1999-2007 Chevrolet Silverado (Classic) Models
1999-2007 GMC Sierra (Classic) Models
2007-2009 Chevrolet Silverado Models (Excluding Hybrid)
2007-2009 GMC Sierra Models (Excluding Hybrid)
Supercede:
This bulletin is being revised to add 2009 to the models. Please discard Corporate Bulletin Number 02-06-04-037D (Section 06 - Engine/Propulsion System).
Condition
Some customers whose vehicles are operated in dusty type environments, such as farming or mining off-road type applications, may comment about the illumination of the check engine light, with a DTC of P0446 (Restricted/Blocked EVAP Vent Path) being set.
Cause
Dirt and dust intrusion into the EVAP canister vent hose assembly, resulting in restricted air flow, may cause this condition.
Correction (1999-2007 Classic/Old Style Models)
After following the published SI diagnostics for P0446 and determining that the EVAP canister vent valve is the cause of the MIL light, replace the existing EVAP canister vent valve assembly with a new assembly. This new assembly is a sealed unit that is designed to be vented through a remote filter box. To ensure correct installation, follow the procedures below.
1999-2003 Model Year (Use Service Kit P/N 19152345)
1. Raise the vehicle. Suitably support the vehicle.
2. Disconnect the EVAP canister vent valve electrical connector, if equipped.
3. Disengage the two vent valve pipe clips securing the pipe to the underbody. Remove the clips from the underbody and discard.
4. Disconnect the vent valve pipe at the EVAP canister.
5. Remove and retain the EVAP canister vent valve bracket mounting bolt.
6. Remove the complete EVAP canister vent valve assembly with bracket attached and discard.
Important
The new canister vent valve will be installed in a new location, outside of the frame.
7. Position and secure the new valve assembly to the frame bracket on the outside of the frame using the existing hole and mounting bolt.
Tighten
Tighten the bracket mounting bolt to 12 Nm (106 lb in).
8. Connect the vent valve pipe to the EVAP canister.
9. Install the two vent valve pipe clips into the existing underbody holes.
10. Connect the EVAP canister vent valve electrical connector, if equipped.
11. Attach bulk 5/8" heater hose to the vent valve port and secure using a clamp. Run a length as needed along the frame rail routing to the area above the transmission.
12. Cut the hose to determined length and install the supplied filter box. Secure using a clamp.
13. Remove the transmission support and lower the transmission assembly as necessary to allow for access to the new filter box location.
14. Secure the filter box to the transmission vent hose just forward of the hose tee-section using a tie strap. DO NOT pinch or restrict the transmission vent hose. The filter box opening should be pointing downward.
15. Raise the transmission and reinstall the transmission support.
16. Tie strap the hose as needed along the frame rail in order to keep the hose away from pinch-points and heat sources.
17. Lower the vehicle.
2004-2007 Model Year (Use Service Kit P/N 19152349)
1. Raise the vehicle. Suitably support the vehicle.
2. Disconnect the EVAP canister vent valve electrical connector.
3. Disconnect the canister pipe from the vent valve.
4. Push in the retainer and remove the existing canister vent valve from the fuel tank clip or mounting bracket. Discard the old valve.
5. Cut back the existing canister pipe approximately 51 mm (2 in) to remove the quick connect end.
6. Install the new canister vent valve to the fuel tank clip or mounting bracket.
7. Cut bulk 5/8" heater hose to a length of approximately 76 mm (3 in). Install the hose between the vent valve and the canister pipe and secure using clamps.
8. Attach bulk 5/8" heater hose to the vent valve port and secure using a clamp. Run a length as needed along the frame rail routing to the area above the transmission.
9. Cut the hose to determined length and install the supplied filter box. Secure using a clamp.
10. Remove the transmission support and lower the transmission assembly as necessary to allow for access to the new filter box location.
11. Secure the filter box to the transmission vent hose just forward of the hose tee-section using a tie strap. DO NOT pinch or restrict the transmission vent hose. The filter box opening should be pointing downward.
12. Raise the transmission and reinstall the transmission support.
13. Connect the EVAP canister vent valve electrical connector.
14. Tie strap the hose as needed along the frame rail in order to keep the hose away from pinch-points and heat sources.
15. Lower the vehicle.
Correction (2007-2009 New Style Models)
After following the published SI diagnostics for P0446 and determining that the EVAP canister vent valve is the cause of the MIL light, replace the EVAP canister vent valve assembly and relocate the remote filter box. To ensure correct installation, follow the procedures below.
Use Service Kit P/N 19152349
1. Raise the vehicle. Suitably support the vehicle.
2. Disconnect the EVAP canister vent valve electrical connector.
3. Disconnect the vent valve pipe quick connect from the canister.
4. Either cut the existing valve vent pipe and leave the remaining section of pipe in the vehicle or remove along with the valve.
5. Push in the retainer and remove the existing canister vent valve from the fuel tank clip or mounting bracket.
6. Cut back the existing canister pipe approximately 51 mm (2 in) and retain the pipe for use with new valve.
7. Connect the canister pipe quick connect to the canister.
8. Install the new canister vent valve to the fuel tank clip or mounting bracket.
9. Cut bulk 5/8" heater hose to a length of approximately 76 mm (3 in). Install the hose between the vent valve and the canister pipe and secure using clamps.
10. Attach bulk 5/8" heater hose to the vent valve port and secure using a clamp. Run a length as needed along the frame rail routing to the passenger side area above the transmission.
11. Cut the hose to determined length and install the supplied filter box. Secure using a clamp.
12. Remove the transmission heat shield, if necessary.
13. Remove the transmission support and lower the transmission assembly as necessary to allow for access to the new filter box location.
14. Secure the filter box to the transmission vent hose just forward of the hose tee-section using a tie strap. DO NOT pinch or restrict the transmission vent hose. The filter box opening should be pointing downward.
15. Raise the transmission and reinstall the transmission support.
16. Reinstall the transmission heat shield.
17. Connect the EVAP canister vent valve electrical connector.
18. Tie strap the hose as needed along the frame rail in order to keep the hose away from pinch-points and heat sources.
19. Lower the vehicle.
Last edited by budhayes3; 05-19-2010 at 11:06 PM.
05-19-2010, 11:01 PM
#7
Here's the thread that stuck out in my head in reference to this code...
https://www.performancetrucks.net/fo...d.php?t=448509
This sounds like it will do the trick 
https://www.performancetrucks.net/fo...d.php?t=448509
Originally Posted by 1slowsilverado
2005 what? Only tsb I show for is for 07-09. But Vehicels (mainly chevy trucks) with code po449 evap vent problem I have found most of the time the connecter to the valve losses ground from the computer. The problem is at the pigtail, the wire turns green and looses connection 3or4 inches from connector. Use pigtail #pt250 to replace the bad connection. Also be sure to use updated valve and relocate the filter.
Last edited by budhayes3; 05-19-2010 at 11:15 PM.
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05-24-2010, 08:59 PM
#9
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Just get the update kit that Budhayes listed there and install it as the bulliten says. GM uses the P0446 for the main cause, but the same issue causes the EVAP vent performance P0449 to set more often than P0446 code.
Tips for install:
To get vent off tank, just pull it down and twist, it will pop right off.
Cut the original hard plastic pipe about 1" from old vent. (use 5/8 heater hose to connect to new vent solenoid.
Run the hose from the top of the valve down the frame rail to the top of the transmission.
Should take about 20 min. to install
Parts: GM# 19152349, about 9' of 5/8 heater hose, 4 clamps and a couple of zip ties.
Tips for install:
To get vent off tank, just pull it down and twist, it will pop right off.
Cut the original hard plastic pipe about 1" from old vent. (use 5/8 heater hose to connect to new vent solenoid.
Run the hose from the top of the valve down the frame rail to the top of the transmission.
Should take about 20 min. to install
Parts: GM# 19152349, about 9' of 5/8 heater hose, 4 clamps and a couple of zip ties.
