CODE P0440 EVAP EMISSIONS

  • Tiny
  • electromdc
  • 2000 Chevrolet Astro
  • 147,000 miles

This van has had this same code reoccur every few days for the last year (since I bought it). I was told that it was just due to a bad gas cap. I replaced the gas cap, and the battery (the battery it came with was very weak). The code stayed away for at least a couple weeks after replacing the gas cap and battery. I have ignored the code since then, until now, because I need to pass emissions testing. I have cleared the code 5 times now, and I run it for at least 2 or 3 drive cycles, and it comes back. The Freeze data showed that it tripped once while cranking (400rpm) so I erased the code and data. And the last time it happend while accelerating (1000rpm 3mph). I have heard that it could be a bad fuel pump, EVAP CANISTER PURGE SOLENOID VALVE, or even just a bad battery. I am not sure where to look first.

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Friday, October 14th, 2011 AT 1:34 PM

7 Replies

  • Tiny
  • mhpautos
  • Expert
  • 30,561 posts

I would be checking all ECAP vacuum hoses first, ensure that they are free from cracks and tight on all spouts, as the care is nearly 12 years old, I would be considering replacing the charcoal canister as well, start here.

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Friday, October 14th, 2011 AT 1:40 PM
  • Tiny
  • Wrenchtech
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  • 20,074 posts

PO440 is a generic code for the EVAP system. There will likely also be more specific codes to help diagnose it but you will likely need a smoke machine to even get started

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Friday, October 14th, 2011 AT 2:12 PM
  • Tiny
  • electromdc
  • Member

EVAP canister is on the driver side of the gas tank, and I inspected both vacuum hoses connected to it, as well as the fat rubber hose. None of them seemed to have cracks or be loose. I purchased a new canister. Might replacing the canister fix the issue, or is that less likely? Or might the leak be in the line further forward on the vehicle (after the vacuum line converts to steel tubing)? How can I check for leaks other than visually, without a smoke machine? Or is it time to take it in, to have them use a proprietary code reader and perform smoke machine test?

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Wednesday, October 19th, 2011 AT 4:10 PM
  • Tiny
  • electromdc
  • Member

I checked the hoses that connect directly to the EVAP canister, all were free of cracks, and securely connected. Should I just replace the EVAP canister and see if that fixes things? Or do I need to pay to have a smoke test done?

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Wednesday, October 19th, 2011 AT 7:15 PM
  • Tiny
  • Wrenchtech
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  • 20,074 posts

You're just spinning your wheels without a smoke machine. That leaks could be anywhere, including one of the solenoids.

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Tuesday, October 25th, 2011 AT 11:07 PM
  • Tiny
  • monkeypaw
  • Member

Check your vacuum hoses and fuel hoses coming from the evapcanister but I'm pretty sure it will be your evap. Purge solenoid, its on the right side of your intake manifold once you pull the cowl/engine cover out from under the dash it has a quick disconnect plastic fuel line going to or just behind the oil pressure sensor you 'll know it when you see it. It has a red 3 prong connector with a blueish colored wire retainer on the top of the plug mine just went out I know its not my fuel pump as its brand new. It has to be the solenoid cuz when id shut it off before you could hear it purge and now you cant hear it purge hope this helps

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Wednesday, June 18th, 2014 AT 6:29 PM
  • Tiny
  • Wrenchtech
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  • 20,074 posts

This was posted 3 years ago. I doubt he needs any further advice. I don't think your wild guess way any help anyway.

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Wednesday, June 18th, 2014 AT 6:38 PM

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