Chevy Colorado and GMC Canyon Fuel System

redshamrockredshamrock Member Posts: 2
I have an 04 colorado crew cab overall i love it. its got about 86000 miles on it. WHEN I bought it (brand new) i had some serious electrical problems and had the bcm replaced 4 times finally fixed!REcently i went to pump some gas and the pumped clicked off at $3...i was on empty so i knew it wasnt full yet!!! So now everytime i go i can hear pressure build up then the pump shuts off and when the pressure is released i can resume pumping. I called the dealership and i got the "well youll have to bring it in so we can teake a look, not a clue what it could be"!! dont really have the $60 bucks for them to check it out, i do all the maintenance myself, spark plugs fuel filter ect, so if anyone has any clue what it could be please let me know


  • poncho167poncho167 Member Posts: 1,178
    Sorry I can't help you with the issue, but most small shops will give you a free estimate of what needs to be fixed. Are you using the same gas pump at the same station?
  • redshamrockredshamrock Member Posts: 2
    i have talked to a few people and they said it could be my "vent control valve" is stuck shut. Any feedback on this would be appreciated and if so any clue where that is located?thanks :confuse:
  • poncho167poncho167 Member Posts: 1,178
    I don't have a Cobalt, but the vent control valve that I think they are referring to should be connected to your air filter system. I could be wrong but there is a valve door on my trucks air cleaner ducting that opens and closes. Mine currently is always in the open position because it doesn't really matter in my truck. There is also an exhaust gas container that contains charcoal for excess fuel vapor flow but this shouldn't be related. I can't say anymore. The only other valves that are related to gas but maybe not in your situation is the EGR (exhaust gas recirculator) valve on my S10's intake manifold.
  • dick28540dick28540 Member Posts: 1
    my dealer told me my 05 colorado needs a fuel filter for $70= . i saw one on internet for 16.00 and wounder how hard it is to relpace, is it inside the gas tank or just on the fuel line thanks.. ;)
  • puregreenpuregreen Member Posts: 24
    Its easy to change on front of tank inline ten min job.
  • poncho167poncho167 Member Posts: 1,178
    I meant Colorado.
  • puregreenpuregreen Member Posts: 24
    I have 5 crew cab 4wd did mine in ten min.
  • brokenallbrokenall Member Posts: 9
    Your filter is just behind your gaz tank
    push type clip no special toll

    hope that help you
  • brokenallbrokenall Member Posts: 9
    I got some problem with my electric purge valve
    when stock close , not able to fill my truck (20 minutes to fill 15 gallons)
    when valve open and stick open when you stop the truck there big odors of gas
    did somebody replace the valve on the canister
    it's located the rear crossmember in front of the spare
  • mikeof48mikeof48 Member Posts: 5
    My 2004 5 cylinder Colorado has 75,000 miles on it. About two months ago when I was filling it with gas, the gas didn,t shut off and it overflowed. I've caught it doing this a couple of times since. Also, when I start it after getting gas, it cranks like it doesn't want to start. It does start but takes a long time compared to other starts. The service engine soon light is on and my mechanic says it's because the new fuel cap doesn't seal properly because the gas tube is bent due to the gas pump nozzles resting on it. This I understand but don't understand why it overflows and starts so hard.
  • leadfoot4leadfoot4 Member Posts: 593
    This doesn't sound right. As far as I know, if the gas pump doesn't shut off it's because THE GAS PUMP'S nozzle isn't set correctly, allowing it to run on after detecting "backflow". That's a safety measure designed into the pump.

    If your gas cap isn't sealing correctly, I could see how that might cause a hard start, as the tank won't pressurize correctly. However, I doubt that the weight of the nozzle alone, would deform the filler neck. On the rare chance that it did, it wouldn't be a hard job to replace the filler neck. It isn't part of the tank. It's a seperate piece that attaches to the truck's bed with 3-4 screws, and a short length of rubber tubing connects it to the tank. If the dealer won't warranty it for you, it shouldn't be an expensive fix.
  • plutacplutac Member Posts: 2
    I have a 04 crew cab colorado I5 86,000. This one is hard to explain, the check engine lite comes on only after the dashboard fuel cap lite comes on, this only happens sometimes. It seems to be more when it gets warmer temps outside. I live in Indiana so the temp. fluciates so much its hard to tell. Im on my third gas cap, i bought the caps at different places thinking one was better than the other. i tried the disconect the battery thing for 10-15 min that shut it off for a day or too. this has been going on for a while now. Can anyone tell me why or how.
  • KCRamKCRam Member Posts: 3,516
    Since changing caps isn't doing the job, you probably need to have your tank vent checked.

    kcram - Pickups/Wagons Host
  • chrisusvichrisusvi Member Posts: 3
    I bought a pre-owned '05 Canyon 2 months ago and I had noticed the engine light was on. I brought it to the shop and they plugged the car into that computer module that reads all the problems with the car. The problem was with the fuel gauge and the sensor in the fuel tank. When the truck was sitting still, the pin on the fuel gauge would slowly go up and down. Never giving a true fuel reading.
    I was driving a hill one day and the truck started to cough and buck. It then stalled. The fuel gauge read a 1/4 of a tank of gas.
    To make a long story short...they put in a new fuel sensor inside the tank. All new parts the mechanic said. $275 worth. I was driving up another hill and what do you know, the truck coughs, bucks and stalls. No gas at 1/4 of a tank again. No 'low fuel' warning light....nothing. From a full tank I waited for it to get to 1/2 and filled it up. At 1/2 of a tank it took 15 gallons. The size of the tank is 19.8 gallons.
    The mechanic doesn't know what to do now.
    This happen to anyone? Any suggestions what the problem is?
  • txspidertxspider Member Posts: 1
    yes, mine is doing this as well ('05 canyon w/">91K miles). I bought a new solenoid ($105 w/shipping) from Just installed it and haven't confirmed it works yet. Here's the issue: the ventilation of the tanks is the problem. A month ago, got the gas cap code (engine light). Replaced the gas cap, no change. The tank never pressurizes and gas always sprays out when the pump shuts off. The vent is apparently open when driving, and closed when pumping (thus no release of pressure as the tank fills up). I'm hoping it's a bad solenoid on the vapor canister, but I'm shooting in the dark a bit. There's another part (purge valve) that I may have to try and it's $18 before shipping. Hope this helps. Appears this will occur on every canyon/colorado when they hit the 100K mark.
  • 2005coloroado2005coloroado Member Posts: 1
    I have a 2005 Chevy Colorado 4wd 5-cyl. (91,000). If my truck sits for awhile while it is running my check engine light will come, after I drive it for awhile the light will reset itself and go off. Well now, the light has come on, and the last three times that I have tried to get gas, the pump will shut off after about 70 cents. I have to stop for a minute and then start again. It takes forever to put as in it. When I unscrew the gas cap I hear a pshhhhh. like air is coming out, can someone help me here.
  • biscuit3biscuit3 Member Posts: 1
    I also have a 05 colorado n have the same fuel problem! Did you find a solution to the problem? If so please let me know! Thanks!
  • gmcustsvcgmcustsvc Member Posts: 4,252
    I am from Gm Customer Service. Have you taken the vehicle to the dealership to have it diagnosed? How long has the problem been going on? Thank you,
    Mariah GM Customer Service
  • n0scuc0n0scuc0 Member Posts: 1
    I have an 04 Colorado crew cab with the same problem after $0.80 it shut off! took it in to check it out all breather lines where fine. after a few shot in the dark quick fix it came out to be EVAPORATOR EMISSIONS CANISTER in the gas tank! as of now seems to be work fine
  • gmcustsvcgmcustsvc Member Posts: 4,252
    Hello N0scuc0,
    I am glad that you found a fix for your vehicle. If you have any further concerns with the vehicle please let me know. Thank you,
    Mariah GM Customer Service
  • leadfoot4leadfoot4 Member Posts: 593
    edited June 2010
    I don't drive my Canyon 4x4 too much in the summer, it's primarily a winter use vehicle. However, a couple of weeks ago, I needed to get a few bags of fertilizer and some mulch for the gardens, so out came the truck. A couple of miles down the road, on goes the "fuel cap" warning message on the dash. The truck's gas cap hadn't been touched in quite a while, but when I get to the garden center, I check it's tight. I get the light again, while on the way home.

    I install a new cap, as it's not too expensive, and thoroughly clean the inside of the filler neck. To test things out, I drive the truck to work the next day, message re-appears on the dash. Get home from work, throw the scan tool on, get "major air leak in vent line" error code, as well as "intermittant lean mis-fire" error code.

    I clean the MAF and throttle body, again clean the filler neck of the tank, and clear the codes. Test drive truck, "gas cap" error message again. Take truck to dealer, they replace the tank vent solenoid. Yes, I have a few months of my GMPP warranty left, so they "cover" the bill, but it's $100 deductable. Yeah, I know that dealer labor isn't cheap, but I know the part, in reality, is about $25-30, and I gave them the error code from the computer, so that minimized their diagnostic time. I also heard that this isn't all that rare of a problem. But, it still cost me $100 out of pocket.

    Yes, I know the truck is 5.5 years old, but it has under 30,000 miles on it...SHEESH! I sure hope that this isn't the beginning of a trend.....
  • marcus3388marcus3388 Member Posts: 1
    2004 colorado I5 motor my gas gauge stopped working day after fill up. Gauge says empty low fuel message on.removed fuel pump from tank checked sending unit with ohm meter resistance gets higher when i raise fuel lever to simulate full tank. Seems to work the way its suppose to also checked voltage 4.29 at plug Anyone know what else i should check. possible BCM needs reset.
  • bc22bc22 Member Posts: 2
    where can i find the canister vent solenoide,it takes forever to fill it up..mechanic said i need to bring it in..i have the part but can't find it..
  • dotzertdotzert Member Posts: 1
    I was having the same problem. We have an 04.I took the bed off.It was located on the frame in front of the spare tire.We took the canister off & hooked it up to a 12 volt charger to see if it was opening &closing.Staying closed all the time.There's a spring on the inside.We took it out & put it on the other side to hold the vent open all the time.Fixed the problem & didn't cost a penny.Hope this helps.
  • bc22bc22 Member Posts: 2
    i have a 2005 colorado 4wd i-5 engine,took thru a car wash and now it shifts hard and won't shift into 4th gear,even tried shifting manually but the problem is still there...any ideas?????
  • gmcustsvcgmcustsvc Member Posts: 4,252
    Hello Bc22,
    Have you had anyone look at the vehicle since the concern started? Did you have any shifting concerns before going to the car wash? Thank you,
    Mariah GM Customer Service
  • repairagainrepairagain Member Posts: 1
    The check engine light and fuel cap light was always on in my 2004 Chevy Colorado. I was tired of spending the money on gas caps, and no one could figure out the problem in Michigan.

    I recently moved to Texas where they have the emissions test. The truck failed due to a leak in the ***** evaporative emission control system*****

    The repair facility had to smoke the system to find the leak. They replaced the evap cannister ($200 for part??) and everything is working fine at the moment, no fuel cap or check engine light.

    now just set back and wait for the next repair
  • the_big_althe_big_al Member Posts: 1,079
    Very interesting... I just acquired a 2004 Colorado with the I-5 motor. It too is throwing the "Check fuel cap" code. Sometimes it will throw on the check engine light, and then switch over to the "check fuel cap" code. It usually only happens if I let the truck idle for a few minutes before driving off.

    It will go away if I shut the truck off and then restart it. But now I am curious as to what this is? It sounds like it really isnt the fuel cap, but something else. It hasnt affected drive-ability yet, but I don't really want it too either. I also don't have a ton of money to throw at it. So if I can do something on my own without spending tons of money on parts that is what I am looking for.
  • leadfoot4leadfoot4 Member Posts: 593
    edited April 2011
    "big-al", read post #22......
  • chevygirl13chevygirl13 Member Posts: 1
    I purchased an '04 Colorado last August. It has overflowed at the pump every time I've not manually shut off. Anyhow, I found this discussion, decided to call Chevrolet and found out that there is an extended coverage on the gas cap- even to secondary owners with expired warranties. Call Chevy at 1-800-630-2438. They will get you in to your local dealership for a look. Hope this helps some of you. :)
  • citrius91citrius91 Member Posts: 2
    j/w if that fixed your problems? thanks jason
  • citrius91citrius91 Member Posts: 2
    05 chevy colorado
    thanks jason
  • akexakex Member Posts: 2
    I've had this vehicle for a year now. Its got about 70K on it and it hasnt been beaten. The problem im having is that I'm not getting the MPG's that its suppose to do, not even close its supposed to do 16 MPG for city driving and 21 MPG for hwy driving. I'm averaging in the summer around 13 MPG and less in the winter. All the things that I could do to help my fuel consumtion I did. Like add a new air filter, did a purge, flushed my oil a couple of times. I dont have big tires, I always try to keep my engine from reving over 2000 RPM. Is this normal? If not what is the solution? Thanks, Alex
  • gmcustsvcgmcustsvc Member Posts: 4,252
    The best fuel economy possible is the direct result of proper maintenance and good driving habits. Listed below are GM's recommendations to achieve the best mileage possible. The first group are things to consider for your vehicle, while the second are tips relating to your driving habits.

    One of the major contributors to poor fuel economy are under inflated tires. Tires low with pressure create drag that the vehicle’s powertrain must overcome, wasting dollars in fuel. Always keep your tires inflated to the proper pressure as shown on the vehicle placard. This not only serves to increase gas mileage but cuts down on tire wear, further decreasing your costs per mile.

    A vehicle that has a dirty air filter can’t efficiently draw air into the engine. This restriction forces the engine to expend energy to "breathe" wasting fuel in the process. Change recommendations are found in your vehicle Owner’s Manual.

    Always use the proper viscosity oil in your engine. Oil that has a higher than required viscosity will create more drag on the internal components of the engine causing more work for it, especially when cold. Each Owner’s Manual contains information on the proper type of oil for your vehicle. Look for the "starburst" symbol on the front of the bottle, and the SM rating on the API circle on the back label. If you are in doubt, stop by your dealer for an oil change, and any other services required. Most current GM vehicles are equipped with oil life monitors to further assist on the "when" to change your oil. (Aveo/Wave/Optra/Epica currently do not have oil life monitors).

    Note: GM Vehicles DO NOT require additional engine oil additives. Some additives may cause harmful effects to the internal seals and additionally void the terms of your vehicles New Car Warranty.
    Purchasing higher than required octane fuel is a waste of money. Using higher octane fuels in a vehicle that only required regular unleaded fuel will neither increase performance nor improve gas mileage. In all cases refer to your owner’s manual and ONLY use the octane rated fuel recommended for your vehicle.

    Even though current GM vehicles have 100,000 mi (160,000 km) service intervals for spark plugs if your vehicle is at that point in its life, have the spark plugs changed to assure proper running and continued efficient, trouble free operation.

    Avoid quick/full throttle acceleration from a standstill in town and high cruising speeds on the interstates. While the optimum MPG for highway cruising speed varies from vehicle to vehicle, faster is almost always worse. If your vehicle is equipped with a Driver Information Center that displays Instant Fuel Economy, select that readout and vary your cruising speed while on the highway. The display will change continuously with uphill and downhill sections but you should quickly be able to identify on level ground the speed range that your vehicle does the best in. Avoid leaving unnecessary items in your trunk. It takes power to move increased weight and that means more gasoline consumption and reduced performance. While the change may be slight, multiplied by thousands of miles, it all adds up. Your vehicle uses much more fuel when the engine is cold. This is especially true in the winter months when the engine will take the longest to warm up. Combine errands or trips so that the vehicle only needs to warm up once to encompass many different stops.

    If you still believe you have a concern please visit a dealer. They will be able to look into the situation.
    GM Customer Service
  • akexakex Member Posts: 2
    Hi Christina,

    Thanks for the reply, I appreciate your time. Everything mentioned above has been addressed and I've also brought it to the dealership and I keep getting the same response I just received from you. Has there been any issues with the fuel injectors, could they be sending too much gasoline then necessary? I'm running out of ideas... Does anyone else have any issues with their Canyon?
  • shareholdershareholder Member Posts: 2
    Hi All,

    I have a 2005 Colorado with 68K miles, the check engine light recently came on, it shows two codes, both P0442. Mine is an I5 engine 4WD, extended cab. I understand this indicates a leak in the evap ssytem, which the sensor checks by trying to hold vacuum. I replace the fuel cap to no avail. Does any one know of a way to defeat this sytem to make the Check engine light go off, like plug the line between the sensor and the tank?

    I bought this truck new, it has been a troublesome vehicle, tire wear that seems to unfixable, water leaks, multiple elctrical problems. I should get 150k miles or 10 years with zero problems, very disappointed in this truck.
  • gmcustsvcsarahgmcustsvcsarah Member Posts: 1,964
    Good morning,

    I understand your frustration, and can appreciate the fact that you are seeking to resolve these concerns on your own. If we could look and see if there are any open recalls or special coverages on your vehicle, we would be happy to do so if you were to email us the last 8 digits of your VIN.

    I realize that working with a dealership is not an option at times, whether due to technical expertise or other factors. If you do decide to work with a dealership in the future, though, I just wanted to let you know that we would like to make sure that things go well. Just let us know through an email (preferably, if you could include your name and contact info, last 8 digits of your VIN, the name of your dealership and appointment information) and we'd be sure to follow up on that.

    Happy Holidays,
    GM Customer Service
  • caoroncaoron Member Posts: 4
    I have 2004 Colorado Z71 Crew Cab With I5 engine and I'm experencing intermittent hesitation on acceleration, expecially when I first drive off after vehicle has been sitting for a while and cold. I have already experenced the Carbon Buildup in the Throttle body and I just cleaned that and I am still experencing the hesitation problem as if it is not getting fuel. After a few seconds it will continue acceleration. Anyone experenced this problem. P.S. Also the engine light comes on for a couple of days and then resets.
  • jibrewer5jibrewer5 Member Posts: 2
    I have an 06 Chevy Colorado, bought it used with 50,000 miles. My husband and I have put about 10,000 miles on it and had no problems until a few months ago. We thought it was the fuses at first because the first time it wouldn't crank one of the fuses had come loose, it happened once more with the fuses so we replaced some of them. Have had issues where I couldn't get it to crank so my husband would drive home from work to only have it start up the first time he tries!! The probem has progressively gotten worse over the last few weeks, where it would happen every once in a while to where it was an everyday, nonstop thing. The last two weeks it has taken longer and longer to get the truck to start up with trying to start it in the ten minute intervals. This past week the time frame went to 15 to 30 minutes of trying to an hour and half sometimes two hours of trying till it would finally start. Three days ago my huband spent an hour and a half trying to get it to start doing the 10 min. of wait time, and it would start and then sputter out and die a few times before it finaly started up and ran just fine. Yesterday we tried it and after two hours of trying couldn't get it to start. So we had it towed to the dealership and it actually did the same thing there, it kept sputtering out and dying on them too! Mechanics are saying it is the fuel pump, that it isn't holding pressure, hooked it up to the machine and showed my husband the gauges and it really isn't! Has anyone else had the problem? I have scoured the forums and seen a lot of Colorados with starting issues but none that end like mine. Just wondering if it really is the fuel pump or should I still be worried about the Passlock system, we thought it was that at first too!
  • jibrewer5jibrewer5 Member Posts: 2
    Oh the mechanics told us that the reason the fuel pump has gone bad is becaus its only driven around the city. I am a stay at home so only do around town driving. I had a Chrysler Mini Van for three years and thats all the driving it got exept for one trip to Florida, never had to replace anything on it!! Their reasonin just doesn't make any sense unless its a design flaw in the system!!
  • gmcustsvcgmcustsvc Member Posts: 4,252

    We're sorry to hear that you've encountered this starting issue with your Colorado. If you would like for us to follow up on this situation with your dealership, please email us at [email protected] (include your name and contact information, a summary of the situation, the last 8 digits of your VIN and mileage, and the name of your involved dealership).

    Sarah, GM Customer Service
  • leasuremanleasureman Member Posts: 5
    hi dick28540:

    i have a 04 Colorado, and the gas filter was very easy to change.
    (or run out of gas). then and only then UNHOOK fuel lines from filter, which IS OUTSIDE,of gas tank. my 04 cost me $15.00 to buy, and my time.
  • leasuremanleasureman Member Posts: 5
    THANK YOU repairagain:
    i am having the same trouble with my 04 colorado, ck lite.
    i have a NEW gas cap, replaced it in 2011, fixed the lite on. but now and then the ck lite will come on and stay on. and the gas pump will shoot gas out tank
    if you stand too close. MUST BE THE BACK PRESSURE, I WILL ck my bleeder relay, on the canister. THANK YOU AGAIN.
  • leasuremanleasureman Member Posts: 5
    ok you will love this problem,
    seems evap system is faulty, but i saw the gas beening put into my truck,
    and as the pump shut off automatic, i saw a gush of GAS behind the gas filler neck.
    So i took off the rear splash shield, to see the FILLER tube, i cked it all, and could NOT find anything loose, or cracked, missing. So i shall watch the next fill up. with the shield OFF, IT DID GUSH BEHIND THE GAS FILLER DOOR.

  • caoroncaoron Member Posts: 4
    I have experienced a similar problem with my 04 Colorado Z71 Crew Cab 3.5 I in the past couple of months. I have encountered a problem of not starting eventhough the engine turns over normally. After sitting for a few minutes and retrying, it started. The last time it took longer for it to start. I came on here to see if I could get some answers as to what was causing the problem. It is as though the ignition was turned off or fuel shut off. I was also concerned that it might be something to do with the security. Did replacing the fuel filter take care of your problem? If so, how expensive was it?
  • HappsterHappster Member Posts: 33
    The gas caps are a chronic problem..,.there is actually an NTSB bulletin...should've been a recall. But if you replace the gas cap and your problem persists, it is a problem in the Eval system. The primary suspect should be the vent solenoid. It is mounted on the charcoal canister in front of the spare tire. It is normally open, but closes for the system check. If it is stuck open or closed, it will trip a code. One person mentioned reversing the spring to keep it open...don't do that. That will just trip a code when the system check can't close it to pressurize the system and check for leaks. Put power to it and see if it opens and closes. If not, tap it and try again. If it starts working, exercise it 20-30 times and then reinstall. If that works, check the cannister - take the hoses off and try to blow through it. If you can't, it is might get away with smacking it around to loosen things up. There is also the purge solenoid up on the engine near the starter (accessed through the left wheelwell). This one is normally closed and opens to purge the canister at appropriate times. If all these things check out, it is either an electrical connector issue or a cracked hose/line. Here is a helpful cut-n-paste from the tech manual and a user's explanation of his fix:

    I seriously think your problem is the Canister vent solenoid / valve or the filter mounted on top of the solenoid. I just had mine out tonight. It took me forever to figure out how to remove it but once I figured it out it was a simple job. My solenoid / valve was sticking and I freed it up.

    First lets make sure you do not have an electrical problem.

    The vent valve is mounted to the charcoal canister. The canister is located just in front of the spare tire under the bed. Find the electrical connector on the vent valve and unplug it. Did you hear it click? If yes, try filling it up with gas and see if it is still hard to get the gas in it. I suspect you will still have a problem filling it but if you don't then you have an electrical problem which we can discuss in a followup posting.

    To get the valve out you do not need to remove the spare tire but doing so gives you a little more room to work. The choice is yours. There are two hard plastic hoses hooked to the canister. Squeeze them by hand to release the clips holding the hoses in place and pull the hoses off of the canister. Then unplug the electrical connector if it is still attached to the valve. If you want to test this canister and valve before removing it, take a piece of hose and slide it over the larger of the two nipples where you removed the hoses from. Put your finger over the small nipple and blow into the test hose you just installed. The air should move freely through the canister and out of the valve. If it does not, continue with the following:

    Laying on the ground look up on the driver's side of the plate the canister is sitting on. There will be a vertical bolt with the threads looking down at you. Undo the bolt from the top down. It is easily accessible with a ratchet or box end wrench. Once the single bolt is out the whole canister assembly will easily lift out of there and you can work on it outside of the truck.

    The vent solenoid is suppose to pass air freely with no power applied to it. You should be able to easily blow air in any port while holding the other port closed with your finger and get the air to come out of the solenoid / valve. I used my mouth to easily blow air through it.

    There is a filter mounted on top of the valve under the 2.5" diameter cap. Gently open the approximately 6 clips with a small screwdriver and the cap will come of. You can now see and clean the filter if necessary. Mine was barely dirty but I cleaned every thing anyway. You can also remove the hard plastic tube that goes between the canister and the valve. Remove it on the canister end by pushing out the white retaining clip until it is completely removed. Then pull of the hose. Now you can blow air through the canister or the valve to determine which one is causing the restriction. The valve also can be completely removed front the canister by lifting the little center tab on the mounting piece of metal and sliding it out of it's track.

    Once you determine which one is causing the problem you can try to free it up or you can replace the failing component. I have not found a good part number for the solenoid/valve yet, but the canister is around $250.00. If the canister is your problem, I would go to a junk yard for a used one.

    In my case it was the valve stuck closed. I was able to tap on it and to get it to open up. I then energized the solenoid 15 or 20 times with a battery to exercise it. It is now working again. Since I only did it tonight I have no idea how long this fix will work. If I can find another valve cheap I will replace it.
  • HappsterHappster Member Posts: 33
    Sorry, here is the clip from the manual:


    The evaporative emission (EVAP) control system limits fuel vapors from escaping into the atmosphere. Fuel tank vapors are allowed to move from the fuel tank, due to pressure in the tank, through the vapor pipe, into the EVAP canister. Carbon in the canister absorbs and stores the fuel vapors. Excess pressure is vented through the vent line and EVAP vent solenoid valve to the atmosphere. The EVAP canister stores the fuel vapors until the engine is able to use them. At an appropriate time, the control module will command the EVAP purge solenoid valve ON, allowing engine vacuum to be applied to the EVAP canister. With the EVAP vent solenoid valveOFF, fresh air is drawn through the vent solenoid valve and the vent line to the EVAP canister. Fresh air is drawn through the canister, pulling fuel vapors from the carbon. The air/fuel vapor mixture continues through the EVAP purge pipe and EVAP purge solenoid valve into the intake manifold to be consumed during normal combustion. The control module uses several tests to determine if the EVAP system is leaking.

    Large Leak Test
    This tests for large leaks and blockages in the evaporative emission (EVAP) system. The control module commands the EVAP vent solenoid valve ON and commands the EVAP purge solenoid valve ON, with the engine running, allowing engine vacuum into the EVAP system. The control module monitors the fuel tank pressure (FTP) sensor voltage to verify that the system is able to reach a predetermined level of vacuum within a set amount of time. The control module then commands the EVAPpurge solenoid valve OFF, sealing the system, and monitors the vacuum level for decay. If the control module does not detect that the predetermined vacuum level was achieved, or the vacuum decay rate is more than a calibrated level on 2 consecutive tests, DTC P0455 will set.

    Small Leak Test
    The engine off natural vacuum (EONV) diagnostic is the small-leak detection diagnostic for the evaporative emission (EVAP) system. While previous leak detection methods were performed with the engine running, the EONV diagnostic monitors the EVAP system pressure or vacuum with the ignition OFF. Because of this, it may be normal for the control module to remain active for up to 40 minutes after the ignition is turned OFF. This is important to remember when performing a parasitic draw test on vehicles equipped with EONV.

    The EONV utilizes the temperature changes in the fuel tank immediately following a drive cycle to use the naturally occurring vacuum or pressure in the fuel tank. When the vehicle is driven, the temperature rises in the tank. After the vehicle is parked, the temperature in the tank continues to rise for a period of time, then starts to drop. The EONV diagnostic relies on this temperature change and the corresponding pressure change in a sealed system, to determine if an EVAP system leak is present.

    The EONV diagnostic is designed to detect leaks as small as 0.51 mm (0.020 in) . The diagnostic can determine if a small leak is present based on vacuum or pressure readings in the EVAP system. When the system is sealed, a finite amount of pressure or vacuum will be observed. When a 0.51 mm (0.020 in) leak is present, often little or no pressure or vacuum is observed. If the test reports a failing value, DTC P0442 will set.

    Canister Vent Restriction Test
    If the evaporative emission (EVAP) vent system is restricted, fuel vapors will not be properly purged from the EVAP canister. The control module tests this by commanding the EVAP purge solenoid valve ON, commanding the EVAP vent solenoid valve OFF, and monitoring the fuel tank pressure (FTP) sensor for an increase in vacuum. If the vacuum increases more than a calibrated value, DTC P0446 will set.

    Purge Solenoid Valve Leak Test
    If the evaporative emission (EVAP) purge solenoid valve does not seal properly fuel vapors could enter the engine at an undesired time, causing driveability concerns. The control module tests for this by commanding the EVAP purge solenoid valve OFF and the vent solenoid valve ON, sealing the system, and monitors the fuel tank pressure (FTP) for an increase in vacuum. If the control module detects that the EVAP system vacuum increases above a calibrated value, DTC P0496 will set.

    The powertrain control module (PCM) sends a class 2 message to the driver information center (DIC) illuminating the Check Gas Cap message when any of the following occur:

    A malfunction in the evaporative emission (EVAP) system and a large leak test fails
    A malfunction in the EVAP system and a small leak test fails
    The evaporative emission (EVAP) system consists of the following components:

    EVAP Canister
    The canister is filled with carbon pellets used to absorb and store fuel vapors. Fuel vapor is stored in the canister until the control module determines that the vapor can be consumed in the normal combustion process.

    EVAP Purge Solenoid Valve
    The EVAP purge solenoid valve controls the flow of vapors from the EVAP system to the intake manifold. The purge solenoid valve opens when commanded ON by the control module. This normally closed valve is pulse width modulated (PWM) by the control module to precisely control the flow of fuel vapor to the engine. The valve will also be opened during some portions of the EVAP testing, allowing engine vacuum to enter the EVAP system.

    EVAP Vent Solenoid Valve
    The EVAP vent solenoid valve controls fresh airflow into the EVAP canister. The valve is normally open. The control module commands the valve ON, closing the valve during some EVAP tests, allowing the system to be tested for leaks.

    Fuel Tank Pressure Sensor
    The fuel tank pressure (FTP) sensor measures the difference between the pressure or vacuum in the fuel tank and outside air pressure. The control module provides a 5-volt reference and a ground to the FTP sensor. The FTP sensor provides a signal voltage back to the control module that can vary between 0.1-4.9 volts . A high FTP sensor voltage indicates a low fuel tank pressure or vacuum. A low FTP sensor voltage indicates a high fuel tank pressure.

    EVAP Service Port
    The EVAP service port is located in the EVAP purge pipe between the EVAP purge solenoid valve and the EVAP canister. The service port is identified by a green colored cap.
  • HappsterHappster Member Posts: 33

    ok you will love this problem,
    seems evap system is faulty, but i saw the gas beening put into my truck,
    and as the pump shut off automatic, i saw a gush of GAS behind the gas filler neck.
    So i took off the rear splash shield, to see the FILLER tube, i cked it all, and could NOT find anything loose, or cracked, missing. So i shall watch the next fill up. with the shield OFF, IT DID GUSH BEHIND THE GAS FILLER DOOR.

    Late to the party, but figured I'd share my experience for those reading the blog these days. '04 Canyon, gas cap light and large leak code. Replaced the cap x 2, no change. I figured the cap wouldn't likely trip a large leak code, so I checked the next usual suspect on these trucks - the vent solenoid on the vapor canister. They are normally open, providing fresh air intake for the vapor canister purges, and close for system pressure checks. I put power to it and it clicked, which usually means they are fine, so I checked the canister and lines for leaks or obstructions. The large line coming from the canister goes to the gas tank and provides the excess vapors for the canister to store and eventually burn. Hard to check this for leaks, beyond smelling for gas vapors. The small line goes to the purge solenoid in the engine compartment (by the starter, left wheel well access I hear), and sends the vapors to the air intake for burning when the PCM sends a purge signal. The purge solenoid is normally closed so I blew into that small line and was unable to...that means the line and the purge solenoid was likely fine (unless it was not opening on command...which I thankfully never had to check). The other lines looked great, no cracks or obvious leaks and I smelled no gas coming from the fuel tank vapor supply line. So I dropped the canister and solenoid for closer inspection. The canister was not obstructed...often they are, but mine was fine. I knew this by blowing into the larger line of the canister while blocking off the vent solenoid line..air came out of the smaller purge line no problem. Then I put power to the vent solenoid while blowing through the intake of the solenoid. I should have been able to blow through it with no power and it should have closed up tight with power. It still clicked, but it was not closing internally...air passed the same whether it was powered up or not. Tough troubleshooting - usually if the solenoid clicks with power they are fine. But on mine, the actuator in the vent solenoid was fine as evidenced by the click, but the internal valve was jammed or otherwise faulty. $121 at Auto Zone and I'm good to go. I also had a problem with gas blowing out of the fill pipe when filling up and I had a P300 multiple misfire code. Hoping this fixes all...I if you don't hear from me again, it did.


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