P0456 - Evaporative emission system leak detected (very small leak)

Check Engine Lights (CEL) suck - but some are easy to fix.  The P0456 can be as simple as a loose/leaking gas cap - or in my case, failing fuel senders (pretty common on Mercedes unfortunately).

When we saw the CEL come on - I grabbed my PLX Kiwi Wireless ODB-II Scanner for iPhone & iPod 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...

PLX Kiwi Wireless ODB-II Scanner for iPhone & iPod
Mercedes e55 cls55 Fuel Pump assy Level Sender RT OEM gas with sensor u…
$527
Genuine 2114701794 Electric Fuel Pump
$555

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

http://www-odi.nhtsa.dot.gov/acms/cs/jaxrs/download/doc/UCM446946/INRL-EA13003-58167P.pdf