JRT600

First my truck- 2005 Silverado 4.3 Liter, 1/2 ton Auto trans. I got the code po449. I found the solenoid vent valve was bad, so I replaced it. I still get the code. I have 12 volts at the valve on the "pink" wire. I jump the valve to see if it works and it does. Now the only other place the problem could be is the wire going to the computer or the computer itself. In the Hayes (s.p.) book it shows a "DRK GRN/WHITE wire going to the computer. I show a white wire only going to the computer. My question is, does anyone have a wiring diagram of which wire plug, that goes into the computer, that would have this white wire. I plan on ohming out this white wire or running a wire from the computer to the solenoid valve to see if it fixes the problem. I am hoping it is the wire and not the computer. The Hayes Book is not real clear on which plug the wire is in.
Thanks Jerry

Mike Sigmond

Here are the ECM & PCM drawings I hope this helps If you need the power distribution schematics let me know.

And Welcome to the forum! stick around its a cool place to visit. Please vote for our ROTM contest, it ends tonight.

shawnvw

DTC P0449
</TABLE><A href="http://gsi.xw.gm.com/si/showDoc.do?docSyskey=1464444&pubCellSyskey=28649&p ubObjSyskey=1464444&from=sm&cellId=28649#ss1-1464444">Circuit Description

A battery voltage is supplied to the evaporative emission (EVAP) canister vent solenoid valve. The control module grounds the EVAP canister vent solenoid valve control circuit to close the valve by means of an internal switch called a driver. The scan tool displays the commanded state of the EVAP canister vent solenoid valve as ON or OFF. The control module monitors the status of the driver. If the control module detects an incorrect voltage for the commanded state of the driver, this DTC sets.
The following table illustrates the relationship between the ON and OFF states, and the OPEN or CLOSED states of the EVAP canister vent solenoid valve.
<TABLE width="95%" border=1><TBODY><TR><TH vAlign=bottom align=middle>Control Module Command

</TH><TH vAlign=bottom align=middle>EVAP Canister Vent Solenoid Valve Position

</TH></TR><TR><TD vAlign=center align=middle>ON

</TD><TD vAlign=center align=middle>CLOSED

</TD></TR><TR><TD vAlign=center align=middle>OFF

</TD><TD vAlign=center align=middle>OPEN

</TD></TR></TBODY></TABLE><A href="http://gsi.xw.gm.com/si/showDoc.do?docSyskey=1464444&pubCellSyskey=28649&p ubObjSyskey=1464444&from=sm&cellId=28649#ss2-1464444">DTC Descriptor

This diagnostic procedure supports the following DTC:
DTC P0449 Evaporative Emission (EVAP) Vent Solenoid Control Circuit
<A href="http://gsi.xw.gm.com/si/showDoc.do?docSyskey=1464444&pubCellSyskey=28649&p ubObjSyskey=1464444&from=sm&cellId=28649#ss3-1464444">Conditions for Running the DTC

<A href="http://gsi.xw.gm.com/si/showDoc.do?docSyskey=1464444&pubCellSyskey=28649&p ubObjSyskey=1464444&from=sm&cellId=28649#ss4-1464444">Conditions for Setting the DTC

<A href="http://gsi.xw.gm.com/si/showDoc.do?docSyskey=1464444&pubCellSyskey=28649&p ubObjSyskey=1464444&from=sm&cellId=28649#ss5-1464444">Action Taken When the DTC Sets

<A href="http://gsi.xw.gm.com/si/showDoc.do?docSyskey=1464444&pubCellSyskey=28649&p ubObjSyskey=1464444&from=sm&cellId=28649#ss6-1464444">Conditions for Clearing the MIL/DTC

<A href="http://gsi.xw.gm.com/si/showDoc.do?docSyskey=1464444&pubCellSyskey=28649&p ubObjSyskey=1464444&from=sm&cellId=28649#ss7-1464444">Test Description


The numbers below refer to the step numbers on the diagnostic table.

1. <LI value=2>Listen for a click when the valve operates. Verify that both the ON and the OFF states are commanded.
   
   <LI value=5>This step verifies that the control module is providing ground to the EVAP canister vent solenoid valve.
   <A name=TD06>
2. This step tests if the EVAP canister vent solenoid valve control circuit is grounded.

<TABLE width="95%" border=1><TBODY><TR><TH vAlign=top align=left>Step

</TH><TH vAlign=bottom align=middle>Action

</TH><TH vAlign=bottom align=middle>Yes

</TH><TH vAlign=bottom align=middle>No

</TH></TR><TR><TD vAlign=bottom align=left colSpan=4>
</TD></TR><TR><TD vAlign=center align=middle>1

</TD><TD vAlign=top align=left>Did you perform the Diagnostic System Check - Vehicle?

</TD><TD vAlign=bottom align=middle>Go to Step 2

</TD><TD vAlign=bottom align=left>

</TD></TR><TR><TD vAlign=center align=middle>2

</TD><TD vAlign=top align=left>

1. <LI type=1>Turn ON the ignition, with the engine OFF.
2. Command the evaporative emission (EVAP) canister vent solenoid valve ON and OFF with the scan tool.

Do you hear or feel a click from the EVAP canister vent solenoid valve when the valve is commanded ON and OFF?

</TD><TD vAlign=bottom align=middle>Go to Step 3

</TD><TD vAlign=bottom align=middle>Go to Step 4

</TD></TR><TR><TD vAlign=center align=middle>3

</TD><TD vAlign=top align=left>

1. <LI type=1>Observe the Freeze Frame/Failure Records for this DTC. <LI type=1>Turn OFF the ignition for 30 seconds. <LI type=1>Turn ON the ignition, with the engine OFF.
2. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records.

Did the DTC fail this ignition?

</TD><TD vAlign=bottom align=middle>Go to Step 4

</TD><TD vAlign=bottom align=left>Go to Testing for Intermittent Conditions and Poor Connections

</TD></TR><TR><TD vAlign=center align=middle>4

</TD><TD vAlign=top align=left>

1. <LI type=1>Turn OFF the ignition. <LI type=1>Disconnect the EVAP canister vent solenoid valve. <LI type=1>Turn ON the ignition, with the engine OFF.
2. Probe the battery positive voltage circuit of the EVAP canister vent solenoid valve with a test lamp connected to a good ground.

Does the test lamp illuminate?

</TD><TD vAlign=bottom align=middle>Go to Step 5

</TD><TD vAlign=bottom align=middle>Go to Step 11

</TD></TR><TR><TD vAlign=center align=middle>5

</TD><TD vAlign=top align=left>

1. <LI type=1>Connect a test lamp between the control circuit of the EVAP vent solenoid and battery positive voltage circuit of the EVAP canister vent solenoid valve at the EVAP vent valve harness connector.
2. Command the EVAP canister vent solenoid valve ON and OFF with a scan tool.

Does the test lamp turn ON and OFF with each command?

</TD><TD vAlign=bottom align=middle>Go to Step 9

</TD><TD vAlign=bottom align=middle>Go to Step 6

</TD></TR><TR><TD vAlign=center align=middle>6

</TD><TD vAlign=top align=left>Does the test lamp remain illuminated with each command?

</TD><TD vAlign=bottom align=middle>Go to Step 8

</TD><TD vAlign=bottom align=middle>Go to Step 7

</TD></TR><TR><TD vAlign=center align=middle>7

</TD><TD vAlign=top align=left>Test the control circuit of the EVAP canister vent solenoid valve for a short to voltage or an open.

Did you find and correct the condition?

</TD><TD vAlign=bottom align=middle>Go to Step 14

</TD><TD vAlign=bottom align=middle>Go to Step 10

</TD></TR><TR><TD vAlign=center align=middle>8

</TD><TD vAlign=top align=left>Test the control circuit of the EVAP canister vent solenoid valve for a short to ground.

Did you find and correct the condition?

</TD><TD vAlign=bottom align=middle>Go to Step 14

</TD><TD vAlign=bottom align=middle>Go to Step 10

</TD></TR><TR><TD vAlign=center align=middle>9

</TD><TD vAlign=top align=left>Inspect for poor connections at the harness connector of the EVAP canister vent solenoid valve.


Did you find and correct the condition?

</TD><TD vAlign=bottom align=middle>Go to Step 14

</TD><TD vAlign=bottom align=middle>Go to Step 12

</TD></TR><TR><TD vAlign=center align=middle>10

</TD><TD vAlign=top align=left>Inspect for poor connections at the harness connector of the control module.

Did you find and correct the condition?

</TD><TD vAlign=bottom align=middle>Go to Step 14

</TD><TD vAlign=bottom align=middle>Go to Step 13

</TD></TR><TR><TD vAlign=center align=middle>11

</TD><TD vAlign=top align=left>Important: If the fuse is open, inspect all related circuits for a short to ground.
Repair the open or short to ground in the battery positive voltage circuit.

Did you complete the repair?

</TD><TD vAlign=bottom align=middle>Go to Step 14

</TD><TD vAlign=bottom align=middle>--

</TD></TR><TR><TD vAlign=center align=middle>12

</TD><TD vAlign=top align=left>Replace the EVAP canister vent solenoid valve.

Did you complete the replacement?

</TD><TD vAlign=bottom align=middle>Go to Step 14

</TD><TD vAlign=bottom align=middle>--

</TD></TR><TR><TD vAlign=center align=middle>13

</TD><TD vAlign=top align=left>Replace the control module.

Did you complete the replacement?

</TD><TD vAlign=bottom align=middle>Go to Step 14

</TD><TD vAlign=bottom align=middle>--

</TD></TR><TR><TD vAlign=center align=middle>14

</TD><TD vAlign=top align=left>

1. <LI type=1>Observe the Freeze Frame/Failure Records for this DTC. <LI type=1>Turn OFF the ignition for 30 seconds. <LI type=1>Turn ON the ignition, with the engine OFF.
2. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records.

Did the DTC fail this ignition?

</TD><TD vAlign=bottom align=middle>Go to Step 2

</TD><TD vAlign=bottom align=middle>Go to Step 15

</TD></TR><TR><TD vAlign=center align=middle>15

</TD><TD vAlign=top align=left>Observe the Capture Info with a scan tool.
Are there any DTCs that have not been diagnosed?

</TD><TD vAlign=bottom align=left>Go to Diagnostic Trouble Code (DTC) List - Vehicle

</TD><TD vAlign=bottom align=middle>System OK

</TD></TR></TBODY></TABLE>

Mike Sigmond

Dam Shawn! you can get all thet secret GM stuff I dont have access to

Nice!

MDTAHOE

If you want access to that stuff sign up for all data on line. It is what most shops use and it is a direct copy of the factory manual (what Shawn has)

Mike Sigmond

Thanks MD, is there a fee? My database is from ARRC with my old login from work in the amusement ride indusrty. ARRC is a section in there along with roller coaster mfg. data etc..

JRT600

Thanks everyone for the info. As soon as this broken leg is healed, I will do further trouble shooting. I will report back as to what I found wrong, but it may be a while. Never fall off a roof, it is not good. Later Jerry

Mike Sigmond

Sorry to hear that Jerry, I wish you a speedy recovery.

steelersfan47

Hello guys, just joined. Looks like a great forum.

Just wanted to say I have a similar problem with my 2005 Silverado Z71, 5.3l that started throwing the po449 code at 42,500 miles (was on a long trip from PA to FL). My FIL put his scanner on it and we cleared it and after two start ups and a little rpm, it would come back. Did this twice. First question, will any damage occur long term if I ride around for a little bit with this condition?
Second, does anyone have any of the diagrams for the 5.3l to tell me where the solenoid is located and can this be had easily at Autozone, NAPA or Advance? Thanks in advance.
Justin

in2pro

Welcome to the forum

short term probably won't cause any harm but it will cause you to fail emissions testing.