P0440 Error Code - JeepForum.com
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post #1 of 3 Old 09-20-2017, 07:34 AM Thread Starter
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P0440 Error Code

Hi all, new to the forum here. Last year I bought an 04 Grand Cherokee (6 cyl.). Thing has been great to me and I'd still like to get many more years out of it.

Recently the check engine light came on with the error code P0440. I changed the gas cap just in case and had to do some other work that required me to unhook the battery (which reset the check engine light). I got about 200 miles and the light came back on.

At 185,000 miles, what are the things I should be looking at to find the culprit?

Thanks in advance!

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post #2 of 3 Old 09-20-2017, 07:43 AM
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2002 WJ 
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Location: Woodstock
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Check the vacuum lines coming from the tank and going to the EGR valve. if the hose or fitting are dry and cracked that will cause the code.

I replaced my gas cap with aftermarket and kept getting the code. I lubricated the o-ring on the cap with silicone so it could get a good seal and the code went away.

2002 Overland - OME 2.5 coils with Kolak special
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post #3 of 3 Old 09-20-2017, 08:51 AM
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I've rarely had a new gas cap fix that problem across various makes of vehicles. It's usually a leak elsewhere in the system.

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