Security indicator light
Nissan Altima / Nissan Altima Owners Manual / Instruments and controls / Warning/indicator lights and audible reminders / Indicator lights / Security indicator light

This light blinks when the ignition switch is placed in the OFF, LOCK or ACC position.
The blinking security indicator light indicates that the security systems equipped on the vehicle are operational.
For additional information, see “Security systems” later in this section.
See also:
Wheels and tires
...
Safety
Standard safety features include antilock brakes, side-impact airbags for the
front seats and side curtain airbags. V-6 models add an electronic stability
system.
For a full list of safety featu ...
Brake system
The brake system has two separate hydraulic
circuits. If one circuit malfunctions, you will still
have braking at 2 wheels. ...
