kenleyf Posted May 28, 2009 Report Share Posted May 28, 2009 DIC indicated loose gas cap the other day although the gas cap was as tight as it would go. Eventually the check engine light came on and I got the warning from the DIC again. Had a local shop clear the codes but again the light came on. Had the codes read again and I am getting PO 449 Evap Cntrl System Vent Valve. The truck is a 2006 VMAX with about 53K miles on it. Where do I start to try to fix this issue? Do I start with replacing the gas cap or is it most likely a solenoid somewhere. I apologize if this has been covered but I searched and did not find it. Any help is much appreciated. Kenley Quote Link to comment Share on other sites More sharing options...
Fireman31 Posted May 28, 2009 Report Share Posted May 28, 2009 According to AllData..... DTC P0449 CIRCUIT DESCRIPTION A battery positive 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. DTC DESCRIPTOR This diagnostic procedure supports the following DTC: DTC P0449 Evaporative Emission (EVAP) vent Solenoid Control Circuit CONDITIONS FOR RUNNING THE DTC The engine speed is more than 400 RPM . The system voltage is between 10-18 volts . DTC P0449 runs continuously once 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. The above conditions are present for a minimum of 5 seconds . ACTION TAKEN WHEN THE DTC SETS The control module illuminates the malfunction indicator lamp (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails. The control module records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the control module stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the control module records the operating conditions at the time of the failure. The control module writes the operating conditions to the Freeze Frame and updates the Failure Records. CONDITIONS FOR CLEARING THE MIL/DTC The control module turns OFF the malfunction indicator lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail. A current DTC, Last Test Failed, clears when the diagnostic runs and passes. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic. Clear the MIL and the DTC with a scan tool. It could be a bad gas cap, but I would lean more towards a defective Vent Solenoid Valve. Quote Link to comment Share on other sites More sharing options...
kenleyf Posted May 29, 2009 Author Report Share Posted May 29, 2009 Thanks for the information. Where is the vent solenoid valve located? Do you happen to have a part number? How hard of a job is it to replace the solenoid and is a plug and play or does it call for some technical expertise? I will probably try the gas cap first because I did get the warning from the DIC that I had a loose gas cap. Again, all help is appreciated. Thanks, Kenley Quote Link to comment Share on other sites More sharing options...
Bad Bowtie Posted May 29, 2009 Report Share Posted May 29, 2009 Your profile info doesn't tell which state you are in. Here in TX we have annual vehicle safety inspections. A few years back these testing stations (service stations & dealerships) were required to have a gas cap tester. Surely, if your state follows similar laws someone could test your cap for free- just to save you some cash before you buy a new gas cap. Quote Link to comment Share on other sites More sharing options...
kenleyf Posted May 29, 2009 Author Report Share Posted May 29, 2009 Good point. I am in the Atlanta, GA area and we do require emissions testing yearly. It passed a couple of months ago but I will take it and have the cap tested again. If it fails, problem solved but if not I assume I am back to the solenoid valve and I do not know where it is located. Any suggestions on a repair manual for the 06 Silverado? Thanks. Kenley Quote Link to comment Share on other sites More sharing options...
Fireman31 Posted May 29, 2009 Report Share Posted May 29, 2009 I believe it is located on the side of the fuel tank........I can grab the repair/replacement procedure for you from AllData tonight........ Quote Link to comment Share on other sites More sharing options...
kenleyf Posted May 29, 2009 Author Report Share Posted May 29, 2009 Great, THANK YOU!!!! Quote Link to comment Share on other sites More sharing options...
Fireman31 Posted May 29, 2009 Report Share Posted May 29, 2009 EVAPORATIVE EMISSION (EVAP) CANISTER VENT SOLENOID VALVE REPLACEMENT REMOVAL PROCEDURE IMPORTANT: Clean the evaporative emission (EVAP) connections and surrounding areas prior to disconnecting the fittings in order to avoid possible system contamination. Raise and suitably support the vehicle. Refer to Vehicle Lifting. Remove the harness clip from the canister vent solenoid (CVS) line. Disconnect the CVS electrical connector. If the vehicle is equipped with a 6 ft box, disconnect the EVAP CVS line from the canister. Remove the CVS clip from the frame crossmember. Push in the retainer and remove the CVS from the fuel tank clip. If the vehicle is equipped with a 8 ft box, disconnect the EVAP CVS line from the canister. Remove the CVS clip from the frame crossmember. Push in the retainer and remove the CVS from the fuel tank clip. If the vehicle is equipped with a 5 ft 8 in box, disconnect the EVAP CVS electrical connector. Disconnect the EVAP CVS line (3) from the canister. Remove the CVS clip (2) from the frame. Remove the CVS bracket bolt (1), if required otherwise push in the retainer and remove the CVS from the bracket. INSTALLATION PROCEDURE If the vehicle is equipped with a 5 ft 8 in box, install the CVS bracket bolt (1) if required, otherwise install the CVS to the bracket until the clip engages. NOTE: Refer to Fastener Notice in Service Precautions. Tighten the bolt to 12 N.m (106 lb in) . Connect the EVAP CVS line (3) to the canister. Install the CVS clip (2) to the frame. Connect the EVAP CVS electrical connector. If the vehicle is equipped with a 8 ft box, install the CVS to the fuel tank until the clip engages. IMPORTANT: On vehicles equipped with a 8 ft box, the CVS line is routed below the frame crossmember. Install the CVS clip to the frame crossmember. Connect the EVAP CVS line to the canister. If the vehicle is equipped with a 6 ft box, install the CVS to the fuel tank until the clip engages. IMPORTANT: On vehicles equipped with a 6 ft box, the CVS line is routed above the frame crossmember. Install the CVS clip to the frame crossmember. Connect the EVAP CVS line to the canister. Connect the CVS electrical connector. Install the harness clip to the canister vent solenoid (CVS) line. Lower the vehicle. Let me know if you need photos, there are like 12 of them LOL. Quote Link to comment Share on other sites More sharing options...
kenleyf Posted May 29, 2009 Author Report Share Posted May 29, 2009 Given my shadetree mechanic status I would greatly appreciate some pictures. If you would prefer to e-mail them to me I can PM you with my e-mail address. I really do appreciate you helping me out. It sounds like a labor intensive project which would cost me big bucks at the dealership not to mention the cost of the part. Just let me know if you want my e-mail address. Thank you!! Kenley Quote Link to comment Share on other sites More sharing options...
Fireman31 Posted May 30, 2009 Report Share Posted May 30, 2009 Given my shadetree mechanic status I would greatly appreciate some pictures. If you would prefer to e-mail them to me I can PM you with my e-mail address. I really do appreciate you helping me out. It sounds like a labor intensive project which would cost me big bucks at the dealership not to mention the cost of the part. Just let me know if you want my e-mail address. Thank you!! Kenley I will PM them to you...... Quote Link to comment Share on other sites More sharing options...
kenleyf Posted June 2, 2009 Author Report Share Posted June 2, 2009 I had the gas cap tested this weekend and it passed so I guess I will tackle the valve solenoid. Thanks Fireman31 for all your help, I will let you know how it goes. Thanks!! Kenley Quote Link to comment Share on other sites More sharing options...
Bad Bowtie Posted June 2, 2009 Report Share Posted June 2, 2009 Keep us posted & good luck. Quote Link to comment Share on other sites More sharing options...
kenleyf Posted June 10, 2009 Author Report Share Posted June 10, 2009 Well, I have chickend out on trying to fix this myself. The solenoid is an expensive part and there is no guarantee that replacing it will fix my problem. Two different shops (one GM one not) confirmed that it could be multiple things causing the code so I had rather not spend a bundle chasing the problem. Thanks for all the help but I think I better let the experts deal with this issue. Kenley Quote Link to comment Share on other sites More sharing options...
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