2011 E90 - Recurring Service Engine Light

I have an '11 335xi sedan, M sport Automatic with 9900 miles.
This week will be the fifth time I am bringing the car back to the dealer to fix whatever is causing the yellow service engine light to come on.
They cannot seem to fix the issue.
The time between each tripped light is about 2 to 3 weeks.
First they just re-set the light, thinking I left the engine on while filling the gas tank. Which BTW - I always turn the car completely off when filling with gas.
Second trip they did it again.
Third trip they said it was a faulty sending unit in the gas tank and replaced it.
Fourth trip, they said it was a faulty gas cap and replaced it.
This week will be the fifth trip in.
Anyone out there with a similar experience?
Additional info: I filled tank with gas and parked car in garage overnight. Next morning smelled gas in the garage and inside the car. No leaks on the garage floor.
What could this be???
Any and all suggestions will be greatly appreciated! Clearly the dealer does not have a clue!
Brett

The car might be detecting a vapor leak especially if you smell gas. My 09 x5 was doing the same thing and the dealer ended up changing every vapor line and vapor pump which I believe is called the DMTL.

Thanx David.
Car is going in Thursday and I will mention this.

They can smoke test the lines for this also.