When we saw the CEL come on - I grabbed my Kiwi WiFi scanner (love this thing!)
Since the car is under warranty - we took it to the dealer to have it evaluated. Needless to say the fuel senders need replaced! I looked up the parts list, and OMG my jaw hit the ground...
Needless to say, these parts aren't cheap - and neither is the labor to install them! Pulling the rear seat, dropping the tank, replacing the pumps - ick! Fingers crossed this gets repaired under warranty.
There's a recall from Mercedes on this issue, but seems to be a recurring issue even after the recall.
EA13-003 – Engineering Analysis to Investigate Allegations of Fuel Leaks at or Near
the Top of the Fuel Tank Assembly in MY 2003-2008 Mercedes-Benz E-Class Vehicles