So Im trying to figure out why my check engine light comes on seemingly when my gas gauge gets low. I noticed the check engine light on sunday and planned to take to the dealership monday, but when I put gas in it, it went off. So today im down to about 31 mls till empty when lo and behold the check engine light comes on again. Could this be a sensor issue or what. I always put 93 in her and shes not due for an oil change till June. Give me some insight Gang

 

Interesting, I've got something similar happening occasionally with my 06 550i. I always user premium fuel as well.

 

You sure its not the fuel light? I wouldnt worry about it. You'll probably never be able to find out. just keep it fueled.

 

Sometime the seal on the gas cap wears prematurely and cause the light to come on. The sensor throws a fault when there's not enough pressure in the fuel delivery system caused by a loose gas cap. New gas cap = $20.

 

What you are referring to would be considered an evaporative system leak. This happens when the fuel tank does not hold pressure or vacuum. This has absolutely nothing to do with fuel delivery.

 

i had a similar problem except mine was more random and had nothing to do with the fuel level. i replaced the gas cap and that did not fix it. dealer pulled the code for me and it was one of the oxygen sensors. It took me 30 minutes to replace and everything is fine again. 2008 550i

 

O2 Sensor was at fault on mine as well......