Rausche Posted October 10, 2009 Report Share Posted October 10, 2009 Alright guys... Go figure I'd return once I needed some advice, right? But that's what this forum is for so I hope you all can help me out some... A few weeks ago my CEL popped on... Aeroforce gauges say it's P0446 (Evaporative Emission Control System Vent Control Circuit)... Alldata told me that there was a TSB out for 2500HDs for this code related to the Vent Solenoid, and that there was an updated part released to replace the stock hardware. I went out and bought the updated kit, which basically just makes the actual vent remote (as in, not directly attached to the solenoid, you use 5/8" hose and put the vent wherever you want). My mechanic and I put the kit in, I cleared the code, and it came back on a few days later... Other than just replacing the entire EVAP system piece by piece I figured I'd ask you all if you anyone has run into this issue before... I'd really like to get out to the drags on the 17th but if I can't get this code shutoff than I won't race the truck... HELP HELP!!! Quote Link to comment Share on other sites More sharing options...
Fireman31 Posted October 10, 2009 Report Share Posted October 10, 2009 (edited) Alex, did you replace the vent solenoid valve itself too, or did you just relocate the vent tube? I just went through this with mine a few weeks ago, not only did we have to relocate the vent tube, but the vent solenoid valve was malfunctioning too, and needed to be replaced. FYI you are supposed to relocate the vent tube down the fuel lines to the top of the transmission tunnel above the transmission per the TSB.....and get ready for the cost of the vent solenoid, around $185. You should be okay to drive/race with that code, it really isn't serious, stupid emmision control stuff....I drove around like that for about a month, including a trip to and from Phili. Edited October 10, 2009 by Fireman31 (see edit history) Quote Link to comment Share on other sites More sharing options...
desrtrat Posted October 10, 2009 Report Share Posted October 10, 2009 .....and get ready for the cost of the vent solenoid, around $185. You should be okay to drive/race with that code, it really isn't serious, stupid emmision control stuff.... i would think that should be covered under your emissions warranty Quote Link to comment Share on other sites More sharing options...
Rausche Posted October 11, 2009 Author Report Share Posted October 11, 2009 Alex, did you replace the vent solenoid valve itself too, or did you just relocate the vent tube? I just went through this with mine a few weeks ago, not only did we have to relocate the vent tube, but the vent solenoid valve was malfunctioning too, and needed to be replaced. FYI you are supposed to relocate the vent tube down the fuel lines to the top of the transmission tunnel above the transmission per the TSB.....and get ready for the cost of the vent solenoid, around $185. You should be okay to drive/race with that code, it really isn't serious, stupid emmision control stuff....I drove around like that for about a month, including a trip to and from Phili. I located the vent up above the gas tank... it's actually wire-tied to my fuel fill tube way up in the bedside. I did the vent solenoid valve as well... That's why I had to use this kit, on my '03 the vent was originally attached to the solenoid, now with this kit it's seperate. And the light is still on after the operation, that's why I'm bugged. I've been driving around on this for a few weeks now and just really want to see it shut off, I know it's not a serious issue but I feel like I'm neglecting the truck when I let things like this slide for so long... Quote Link to comment Share on other sites More sharing options...
kweber1911 Posted October 12, 2009 Report Share Posted October 12, 2009 how tough is this to do yourself? i have the same code on my truck and want to get it fixed. also, how much did it cost when all said and done? I have also heard that the gas cap could be the problem, should i try to replace that first. Quote Link to comment Share on other sites More sharing options...
delay18 Posted October 12, 2009 Report Share Posted October 12, 2009 A gas cap shouldn't give you that code. Vent valve are extremely common on the 1/2 and 3/4 tons. The TSB referred to here has you relocate the new vent valve towards the front of the box. If I remember right the problem they were having was these things getting gummed up from being on top of the tank and dirt getting thrown up there. I'm at work now so I will see if I can pull up that tsb as well as some trouble shooting tips. Quote Link to comment Share on other sites More sharing options...
Rausche Posted October 14, 2009 Author Report Share Posted October 14, 2009 how tough is this to do yourself? i have the same code on my truck and want to get it fixed. also, how much did it cost when all said and done? I have also heard that the gas cap could be the problem, should i try to replace that first. It's a little tricky since you need to get on top of the gas tank. I chose to drop the tank, but it might just be easier to grab a couple buddies and lift the bed off the truck. Other than it's pretty simple and self explanatory. A gas cap shouldn't give you that code. Vent valve are extremely common on the 1/2 and 3/4 tons. The TSB referred to here has you relocate the new vent valve towards the front of the box. If I remember right the problem they were having was these things getting gummed up from being on top of the tank and dirt getting thrown up there. I'm at work now so I will see if I can pull up that tsb as well as some trouble shooting tips. I don't think a gas cap can trigger P0446... Any advice you could give me would be great, TIA. Quote Link to comment Share on other sites More sharing options...
delay18 Posted October 14, 2009 Report Share Posted October 14, 2009 (edited) I don't think a gas cap can trigger P0446... Any advice you could give me would be great, TIA. I know. I was saying it is likely not the culprit in reference to what kweber asked. Anyway this is right from GM Service Info. DTC diag tree. I did notice a few TSB's regarding P0446. One of which was the relocation of the vent. Another referred to a possible cracked canister. Let me if this doesn't help and I can get you the TSB's. Sorry everyone, this thing is long. Rob EDIT: For some reason the flow chart is not showing up properly. After reviewing it, it is going to be hard to use anyway unless you have a scan tool. Is there anyway you can get a hold of a scan tool? I can send you the trouble tree in an email or something if you can. I threw in that TSB about the canister. System Description This DTC tests the evaporative emission (EVAP) system for a restricted or blocked EVAP vent path. The control module commands the EVAP canister purge solenoid Open and the EVAP canister vent solenoid Closed. This allows vacuum to be applied to the EVAP system. Once a calibrated vacuum level has been reached, the control module commands the EVAP canister purge solenoid Closed and the EVAP canister vent solenoid Open. The control module monitors the fuel tank pressure (FTP) sensor for a decrease in vacuum. If the vacuum does not decrease to near 0 inches H2O in a calibrated time, this DTC sets. Conditions for Running the DTC • DTC P0106, P0107, P0108, P0112, P0113, P0116, P0117, P0118, P0120, P0121, P0122, P0123, P0125, P0131, P0132, P0133, P0134, P0135, P0137, P0138, P0140, P0141, P0147, P0151, P0152, P0153, P0154, P0155, P0157, P0158, P0160, P0161, P0167, P0220, P0442, P0443, P0449, P0452, P0453, P0455, P0502, P0503, P1111, P1112, P1114, P1115, P1120 are not set. • The ignition voltage is between 10-18 volts. • The barometric pressure (BARO) is more than 75 kPa. • The fuel level is between 15-85 percent. • The startup engine coolant temperature (ECT) is between 4-30°C (39-86°F). • The startup intake air temperature (IAT) is between 4-30°C (39-86°F). • The startup ECT and IAT are within 9°C (16°F) of each other. Conditions for Setting the DTC • The fuel tank pressure sensor is less than -10 inches H2O. • The above condition is present for more than 30 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. Diagnostic Aids • An intermittent condition could be caused by a damaged evaporative emission (EVAP) vent housing, a temporary blockage at the EVAP vent solenoid inlet, or a pinched vent hose. A blockage in the vent system will also cause a poor fuel fill problem. • For intermittent conditions, refer to Intermittent Conditions #03-06-04-037: Service Engine Soon Light On with DTC P0446 Set (Replace Canister) - (Jul 31, 2003) Models:2003 Chevrolet Silverado 2003 GMC Sierra with 4.3L, 4.8L, 5.3L, 6.0L or 8.1L Engine (VINs W, X, V, P, T, N, U, G - RPOs L35, LU3, LR4, LM4, LM7, LQ9, LQ4, L18) <A href="http://gsi.xw.gm.com/si/showDoc.do?docSyskey=1363022&from=sm#ss1-1363022"> Condition Some customers may comment on the Service Engine Soon light being illuminated. Upon investigation, the technician will find a DTC P0446, EVAP system blocked or restricted vent path. <A href="http://gsi.xw.gm.com/si/showDoc.do?docSyskey=1363022&from=sm#ss2-1363022"> Cause Variation in flow restriction through the EVAP canister may cause the new diagnostic to set the code. <A href="http://gsi.xw.gm.com/si/showDoc.do?docSyskey=1363022&from=sm#ss3-1363022"> Correction Check the system operation using the current diagnostics for P0446. If diagnostics lead you to replace the EVAP Canister or no concerns are found, then replace the EVAP canister and bracket. A new canister has been released with pelletized charcoal instead of powdered charcoal. This allows for a less restricted, more consistent flow through the canister. <A href="http://gsi.xw.gm.com/si/showDoc.do?docSyskey=1363022&from=sm#ss4-1363022"> Parts Information Part Number Description Qty 15175906 Canister, EVAP 1 15175907 Bracket, EVAP Canister 1 Parts are currently available from GMSPO. <A href="http://gsi.xw.gm.com/si/showDoc.do?docSyskey=1363022&from=sm#ss5-1363022"> Warranty Information For vehicles repaired under warranty, use: Labor Operation Description Labor Time L0620 Canister, Fuel Vapor - Replace Use Published Labor Time GM bulletins are intended for use by professional technicians, NOT a "do-it-yourselfer". They are written to inform these technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions, and know-how to do a job properly and safely. If a condition is described, DO NOT assume that the bulletin applies to your vehicle, or that your vehicle will have that condition. See your GM dealer for information on whether your vehicle may benefit from the information. WE SUPPORT VOLUNTARY TECHNICIAN CERTIFICATION Subject:Service Engine Soon Light on with DTC P0446 Set (Replace Canister) Edited October 14, 2009 by delay18 (see edit history) Quote Link to comment Share on other sites More sharing options...
Merc Dr. Posted October 21, 2009 Report Share Posted October 21, 2009 Is there an update on this yet? I think I have the same problem. I had a friend check the code and it said it was an evap problem. I checked the gas cap and it had a split o-ring. I put a new cap on and the CEL hasn't gone away yet(4 dys). Is there a way to test the vent relay or cannister so I'm not just throwing parts at it? Quote Link to comment Share on other sites More sharing options...
Fireman31 Posted October 21, 2009 Report Share Posted October 21, 2009 Is there an update on this yet? I think I have the same problem. I had a friend check the code and it said it was an evap problem. I checked the gas cap and it had a split o-ring. I put a new cap on and the CEL hasn't gone away yet(4 dys). Is there a way to test the vent relay or cannister so I'm not just throwing parts at it? The only way to test the vent solenoid valve is with a scan tool like a GM Tech2, Snap-On Modus or Solus, or a Mastertech...... Quote Link to comment Share on other sites More sharing options...
Drbeam89 Posted September 21, 2012 Report Share Posted September 21, 2012 I know this has been on here for some time but has anyone found anything else that could casue the 0446 code? I have a 2004 SSS and have this code as well. I have replaced the vent valve with the new remote filter kit. The old one was full of dust. I was also having problems filling the tank. It kept clicking off like it was full even when empty. Still having issues with filling tank and the code came back after about 4 days. Cleared the code by diconecting the negative battery the first time. Today I cleared it with a scanner and will see how long before it comes back on. TIA, Quote Link to comment Share on other sites More sharing options...
cb2big4u Posted September 21, 2012 Report Share Posted September 21, 2012 It can be other issues with emission devices or as stated a faulty gas cap. As far as the filling up at the pump goes. Mine does it all the time. Gas is just frothy sometimes. Beat time to fill up is in the am when its not heated up yet. Less air in it and get more for what u pay for. I usually have to pull the nozzle out a little to get it to fill on its own without clicking off here in Florida. Sent from my ADR6425LVW using Tapatalk 2 Quote Link to comment Share on other sites More sharing options...
Drbeam89 Posted September 24, 2012 Report Share Posted September 24, 2012 (edited) Had the CEL reset and then it came back on 3 days later. Also filled the tank again and this time it worked fine. Not sure why it clicked off like before after I changed the vent valve solinoid. So guess the only problem now is the pesky CEL. Edited September 24, 2012 by Drbeam89 (see edit history) Quote Link to comment Share on other sites More sharing options...
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