PCM Code Help

Discussion in 'GM Powertrain' started by Dirtysailor, Sep 24, 2010.

  1. Dirtysailor

    Dirtysailor New Member

    I have two codes coming up on my PCM. P0449 and P0455. Respectively these are

    Evaporative Emission Vent Solenoid Control Circuit
    Evaporative Emission (EVAP) System

    So does anyone know what may be going on with the truck and what I need todo the correct/fix it? At least where to start?

    At the advice of the parts guy, he said that changing the gas cap might help. Did that nothing changed, one point for the parts guy for selling something. :grrrrrr:

    Truck is a '03 ext cab 1500 with a 5.3 & 4x4.
  2. murdog94

    murdog94 Epic Member 5+ Years 5000 Posts

    Sounds like the Evap Solenoid is shot. fairly common fault on these trucks. If you do a little searching on the site here there are a few threads that talk about this and peoples fixes..
  3. Dirtysailor

    Dirtysailor New Member

  4. murdog94

    murdog94 Epic Member 5+ Years 5000 Posts

    That is the valve the one under the hood is the solenoid as far as i understand.
  5. TrailLeadr

    TrailLeadr Epic Member 5+ Years 1000 Posts

    This is the exact pair of codes I got on my '06 Avalanche when my vent valve went bad. This would be the same part as in the other thread.

    Part #:25932571

    I know this doesn't help a lot, but since the codes are kind of ambiguous it could still be the valve under the hood. But I'm willing to bet it's the canister near your fuel tank.
  6. Dirtysailor

    Dirtysailor New Member

    Is there a procedure on here how to clean the vent valve? I swore I read one before, can anyone link me it as I have yet to be able to find it again.
  7. Sam_A

    Sam_A Rockstar 100 Posts

    I had the P0449 code on my 04 Z71 about 2 months ago and had to replace the solenoid above the gas tank. Some people have done it themselves (I think there is a forum on this site where someone did that), but I opted to take it to the dealership. They charged $300 parts & labor and it fixed the problem.
  8. Crawdaddy

    Crawdaddy All hail the Mad King!! Staff Member 5+ Years 1000 Posts Platinum Contributor

    In defense of the parts guy, usually when a person has evap system issues, it is quite commonly a gas cap. As a result, the parts counter guys will default to replacing the gas cap as the simplest and cheapest repair to test. Now, that doesn't mean that he's always acting in your best interest, but it is what it is.

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