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Old 10-29-2012, 08:44 PM
Skarv Skarv is offline
Officially Welcomed to the 'Fest
Location: Silicon Valley
Join Date: Oct 2010
Posts: 135
Mein Auto: '05 645i convert
This one can be really easy, or relatively hard. I'd try the easy first just in case. I went the other way and did several jobs that weren't needed... thought at 80K, my car could probably use the new Thermostat and CCV valves. Those are two things that apparently often throw the Increased Emissions signal. If you are at all handy, you can do both jobs for about $150 worth of parts.

The other area that triggers this warning is when the car senses that vapor is escaping from the gas tank. Hence the emissions. This generally happens two ways: One is if the fuel vapor pump fails. This little item only costs about $130, but I hear it isn't fun to install. Gets mounted under the car to the side of the fuel tank. I don't know how hard this is, but this is what the code reader said was my problem when I finally got to read actual ODB codes. But it turns out that even though it signaled this, what was really wrong was....... the GAS CAP.

SO before you go down the rathole, I suggest check your gas cap. I was about to just buy a new one when an out of stock/wife situation delayed that strategy. So I figured out how to fix it. And it cured my problem. The link to my 10minute DIY is below. You can tell if this is part of your problem if when you put on your gas cap, you can feel it hit the stops before the ratcheting. It should tighten tighten tighten and then as the pressure builds, the ratchet goes off. If yours has been overtightened, the tabs got bent and it now bottoms out and doesn't seal well.

Going on a month with no recurrence. Your mileage may vary, but I wish I had started here, not ended.

Check it out, or just buy a new gas cap. They are only about $20.
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