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P0440 diagnostic chart ?

Discussion in 'Chevy Trucks' started by ghlkal, May 20, 2009.

  1. ghlkal

    ghlkal Member
    Messages: 83

    My 2002 1500 with 5.3 is throwing a P0440. I know this is the evap system, and I know it could be several things, including a line leak.

    Rather than just "trying stuff," I'd like to follow a plan to diagnosis and locate the problem.

    Does anyone have a chart, perhaps from the service manual, with the steps to follow? :help:

  2. B&B

    B&B PlowSite Fanatic
    Messages: 12,777

    Without a Tech II scanner or some other scanner with bi-directional controls to manually operate the vent solenoid and cannister purge solenoid there isn't much you can do, with or without a flow/diagnostic chart. The best you can do is check the lines and hoses for leaks and throw a fresh gas cap on it, thats about all without shotgunning it.

    The purge solenoids never go bad but the vent solenoids do on occasion, so that would be the next bullet in the shotgun.
  3. Gear_Head

    Gear_Head Senior Member
    from IL
    Messages: 245

    it was a vent solenoid on my 05 5.3.
  4. KSikkema

    KSikkema Senior Member
    Messages: 179

    vent solenoids 98% of the time. there is an updated one from GM that relocates the solenoid closer to the cab as opposed to the factory mounted location
  5. ghlkal

    ghlkal Member
    Messages: 83

    Thanks for the feedback, guys.

    Where is the vent solenoid? It's not above the gas tank, is it? :mad:
  6. MickiRig1

    MickiRig1 PlowSite Veteran
    Messages: 3,617

    Might even try unbolting the charcoal canister and see how heavy it is.If it weights a few pounds this could be a problem. If you replace the purce solenoid and it still throws the code this may be the problem. It's absorbed so much gas and water that the purge will never clear it. Like B&B said look at the purge line from end to end. They use very thin /cheap tubing on it. The BIG RED DRAIN has about 3 foot of rubber hose fixing it's vent line.
  7. B&B

    B&B PlowSite Fanatic
    Messages: 12,777

    Although Micki's tips would be very useful if you had a restriction type code (P0442, P0443, which you don't) they're still very good tips when dealing with an EVAP system issue...and especially so on an older vehicle. I've done the 'canister shake' many times when dealing with an EVAP restriction issue and it's very easy to identify a plugged canister that way. :salute:

    If you end up that the vent solenoid is the issue it's located/mounted just in front of the left front bed mounting bracket, just to the left of the fuel tank. Takes some arm wiggling to get your hands in there on order to gain access to the electrical connectors but its not a bad job.
  8. ghlkal

    ghlkal Member
    Messages: 83

    Thanks for your help everyone, I appreciate it.

    BTW, B&B, you're a real asset to this forum. Your posts are helpful and beneficial - thanks for sharing your knowledge :salute:
  9. RichG53

    RichG53 PlowSite.com Addict
    Messages: 1,135

    Do those canisters self drain or do they need regular maintenance???
  10. B&B

    B&B PlowSite Fanatic
    Messages: 12,777

    Thats what were here for.

    ...most of us anyway. [​IMG] :D
  11. B&B

    B&B PlowSite Fanatic
    Messages: 12,777

    The canisters do not require maintenance Rich. They either work correctly or they don't. When they don't the MIL light will let you know. :angel:
  12. RichG53

    RichG53 PlowSite.com Addict
    Messages: 1,135

    Thanks ! ! ! I never heard of them needing any maintenance but thought I would ask ! ! !