Actually, the term "electronically," may not be too far off. The mechanic may be talking about a EBDT code (hope I got the acronym correct). You can read these codes with a scan reader. If your engine displays the icon of "service engine" soon, it may indicate a code related to the gas tank vaccum valve or canister, which filters gas tank gases before allowing them to escape from the gas tank and re-routes them to the engine so that the gas tank does not vent gasses into the athmosphere. When the check valve goes bad, it causes a problem when trying to deliver gas to the gas tank.