Smart Key battery

See also:

Safety, Reliability & Mileage
Because the E-Class has been redesigned, we don't yet have predicted reliability ratings for this model. Furthermore, the 2010 E-Class hasn't yet been crash-tested by our preferred source, the Ins ...

4MATIC (permanent four-wheel drive)
4MATIC ensures that all four wheels are permanently driven. Together with ESP® and 4ETS, it improves the traction of your vehicle whenever a drive wheel spins due to insufficient grip. WARNI ...

Important safety notes
WARNING When leaving the vehicle, always remove the SmartKey from the ignition lock. Always take the SmartKey with you and lock the vehicle. Do not leave children unsupervised in the vehicle ...