Toyota Lexusc Owner's Handbook Manual page 498

(l) Vehicle-to-vehicle distance control mode failure
warning
"
1 Warning code 2 "CRUISE" indicator light
Master warning light
3
If there is trouble somewhere in the dynamic laser cruise
control while the vehicle-to-vehicle distance control mode is
on, the master warning light comes on and the alarm sounds,
and one of the warning codes "E1", "E2" or "E3" will appear on
the display. Dynamic laser cruise control is automatically
cancelled.
If "E3" appears on the display, the "CRUISE" indicator light in
the instrument cluster also flashes.
STARTING AND DRIVING
If "E1" appears on the display, the system cannot easily
measure the vehicle-to-vehicle distance because of a dirty
laser radar sensor glass while the dynamic laser cruise control
is on.
If this code appears, clean the sensor glass with a soft cloth
and try setting the preset speed again. If the dirt is removed
without cleaning, the system will automatically enter the ready
mode.
If the system does not enter the ready mode even after
cleaning or the code remains on the display, the system might
be malfunctioning. Although there is no problem to continue
driving, please contact your Lexus dealer.
CAUTION
Always keep the sensor glass and never allow it to be
covered with icicle or any substance, so it can detect the
vehicle in front.
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