Question about 2000 Buick Century

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P0440 code is on I cant figure out what could be causing the code to come on I put a scanner on to erase code it stays out for aweek then comes back on

I need to find out what the problem is ialready checked the gas cap

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The gas cap could be defective so replacing it may be the cheapest fix if it works. I have seen in many cases the problem is more difficult to fix that just replacing the gas cap. I would suggest trying that first before taking to the shop . The tech will most likely smoke test the system for leaks first and if none are found they should use the bidirectional controls on a scan tool to operate the evap systems individual components to make sure they are working. Goodluck

Posted on Nov 13, 2014


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