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2000 Forester Manual
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38 Posts
Discussion Starter · #1 ·
I've only had my 2000 manual forester for a short while and I need to get it smogged. When I got it I got a CEL on the way home after buying it and I've been trying to get it ready for smog since then. The original CEL was a P0420 code that I cleared and then checked and cleaned various things.
I then took it to get smogged and the exhaust portion of the test passed with flying colors however I failed because the computer couldn't communicate with the OBD II. I drove it home which then popped up a new CEL code, P0440.

I suspect that the reason the computer couldn't communicate was because the ECU was in not ready mode (the smog tech didn't say that and only suggested that the wires might be corroded).

The P0440 could be caused by many things (I've checked the fuel neck for leaks) and one of those things could be a loose gas cap. If I tighten the gas cap do I need to clear the CEL or will it auto correct itself after some time?

The tags are expired otherwise I'd just drive it more, instead I must try to minimize driving so I don't get a ticket. Which is also why I don't want to reset the ECU because I will then have to drive it to get out of the not ready mode.
 

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2004 Forester XT Premium 4EAT
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29,432 Posts
I would start with a new gas cap. You can clear the CEL if you want, but the code will remain stored for a certain amount of miles, so you'll have to drive it first and see if the CEL returns. The DMV will issue you an extension under certain circumstances if your tags are expired.

If the computer at the smog station can't connect with the ECU at all, then that might be a separate problem altogether.
 

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2000 Forester Manual
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38 Posts
Discussion Starter · #4 ·
I don't know why a multi thousand dollar smog machine won't connect but my $200 wideband scanner connects just fine.
 

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2000 Forester Manual
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38 Posts
Discussion Starter · #5 ·
Upon further research I may have found the issue but I'll still need to test it to see if I fixed it.

While trying fix another issue I had removed the fuel pump from the gas tank. When I reinstalled the fuel pump I stripped one of the bolts which caused the fuel pump cover not to seal properly. This may cause the evap system to not have its proper vacuum which I would think would cause the p0440 code. To fix my issue I used a gasoline compatible sealant and ran a bead of it on both sides of the rubber gasket that sits in between the gas tank and the fuel pump cover.
I'm hoping that sealed it so I'm going to clear the code and see if it comes back. I'll update the thread later.
 

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2000 Forester Manual
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38 Posts
Discussion Starter · #6 ·
Well damn! The P0420 code came back before I could test the code reset. I'm doing some more work (new valve cover gasket which will hopefully stop the leak that keeps messing up my upstream O2 sensor). I'll replace the sensor if this next round of fixes doesn't work.
 

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2007 FXT Limited 5MT
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2,815 Posts
You need a proper gasket on that fuel tank. Get a new oem one, and fix that stripped bolt. I also would throw a new gas cap on it, they are cheap enough and without the proper tools you're just gonna have to load up the parts cannon lol. If you fix the gas tank gasket and it comes back, you should take it to a shop and have them smoke the evap system, they'll find the leak very quickly with that.
 
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