Mercedes-Benz CL Operator's Manual page 335

Driving systems
333
Switch on Active Lane Keeping Assist using
X
the on-board computer ( page 349).
Y
Symbol : appears in the instrument
cluster.
If your speed exceeds 40 mph (60 km/h)
and lane markings are detected,
symbol : is highlighted in green. Active
Lane Keeping Assist is ready for use.
Z