The dealer ran a full diagnostic. The only thing that came up was the gas cap trouble code.

My friend has a BMW X-5. During the first week of ownership, his check engine light came on. The dealer reset it and told him it was a loose gas cap. That happened to him a couple of more times in the next several tankfuls. He told the dealer to fix it, or give him a new car. The dealer kept it for 3 or 4 days. After the BWM factory mechanic worked on it, he discovered a check/bleed valve in the fuel system that had a small leak which triggered the gas cap trouble code. After replacing that valve, the check engine light has not come for 15,000 mi and counting.

My check engine light came on at about 1/8 tankful. He told me to keep an eye on the fuel level to see if it happens again at 1/8 tankful.

My question is, is there such check/bleed valve in the fuel system of the V70 that could possibly trigger the gas cap trouble code ? Thanks.