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GM Techs...need help with P0451 code on 2011 Suburban

Discussion in 'General' started by njracer, Mar 9, 2018.

  1. njracer

    njracer Well-Known Member

    Short story...

    I got gas on Monday and only drove a few miles and went home. Next morning used the auto-start and then headed off to a meeting. Came out of the meeting (it was snowing) so I went to auto start and nothing. Started the car and the check engine light came on. This was not on when I drove to the meeting. Had Auto Zone pull the code and P0451 came up. Guy said it was most likely the gas cap is not on correctly. Checked it and sure enough the plastic strap was wedged under the cap. Put cap on correctly and have use the truck a few times driving a good 15 to 20 mi. Light still on.

    So it looks like it's the FTP and going by what I can find on YouTube, this is something that I'm going to have to take to the dealer or local repair guy.

    Couple of questions:

    1. Is there an easy way to replace this or do I have to drop the tank?
    2. Would the check engine light being on prevent the auto-start from working?
    3. Also noticed that the AC light will not come on. If I press it it will light up, flash one or two time and go off.

    Anything else I should check?

    BTW, I've owned the truck since new and it has about 88K on the clock. Also, I don't have Broom $$$$$ so throwing the truck away and buying a BIG ASS DIESEL is not an option. ;-)

    Thanks,

    Brian
     
  2. Mongo

    Mongo Administrator

    Did Auto Zone reset the CEL? If not unhook the battery for a few to do it. Had some issues with mine last week and it took half a dozen times driving it before the light reset on it's own.
     
  3. BSA43

    BSA43 Well-Known Member

    IIRC, the code set by a loose or missing fuel cap will reset itself after several engine start cycles if the cap problem is fixed; I forgot how many, but it's less than 2 dozen.
     
  4. bored&stroked

    bored&stroked Disclaimer: Can't spell

    Autozone will not reset codes, liability thing.
    Get the code reset. See if it comes back before changing parts.
     
  5. Mongo

    Mongo Administrator

    Had a feeling they didn't. Either drive it another week before worrying or pull the negative cable for a bit to reset it all.
     
  6. CB186

    CB186 go f@ck yourself

    Buy a Bluetooth/wifi OBDII reader and a diagnostic apparently such as Torque and be able to pull and reset codes yourself.
     
    cha0s#242 likes this.
  7. Mongo

    Mongo Administrator

    Screw that, I want a Diablo Sport Tuner :D
     
  8. njracer

    njracer Well-Known Member

    Mongo wins PIE! Disconnected the battery, engine light is off, AC and auto start works again! Fingers crossed this was due to the gas cap and nothing else.
     
  9. Mongo

    Mongo Administrator

    Most likely all it was since that's the only code they read.
     
    red2002 likes this.
  10. Spitz

    Spitz Well-Known Member

    Autozone sells a shit ton of gas caps FWIW. If you did find something like that cap then yes, definitely clear the code and drive it to see. Yes the CEL will inhibit remote start, not sure about the A/C but apparently it must, never ran across that. If you need to replace a fuel cap go OEM only.

    If you end up with the issue again its best to get it to a shop that has the capability to control the Evap system to see whats going on. Most common fix on my repair data says FTP sensor but that's not concrete obviously. At least GM's Evap systems are simple. Evap system problems crop up in the spring time due to ambient temps. A lot of the Evap monitors don't run unless ambient is above 35*F as fuel doesn't evaporate a lot at low temps. We get a rash every year in about the next month we'll see one a day.
     
    BHP41 likes this.
  11. Banditracer

    Banditracer Dogs - because people suck

    Put a piece of tape over the light. Fixed. :p
     
  12. assjuice cyrus

    assjuice cyrus Well-Known Member

    Yes, it would of went out but it wants to see x amount of key cycles before it will turn it off. Miles won't matter.
     
  13. BHP41

    BHP41 Calling out B.A.N. everyday

    Yep, it just hadn’t run the test again so it didn’t turn the light off itself. For everything else, Spitz is spot the eff on.
     
  14. 88/532

    88/532 Simply Antagonistical

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