All of Land Rover's Discovery II automobiles are fitted with electronic antitheft alarm systems that also include engine immobilisation. Options include Superlock, which immobilises interior door handles. The system is controlled by a remote-control unit that also can lock and unlock the doors. The status of the alarm can be diagnosed through a light and the horn.
Look at the instrument cluster and identify the alarm-status light. It is approximately in the centre of the cluster, just below the speedometer and tachometer.
Press the lock button on the remote control and watch the alarm-status light to diagnose the status of the car alarm. If the light flashes rapidly, the alarm is arming itself. If the light slows to a more moderate flash after 10 seconds, the alarm is set. If the light flashes slowly, or is illuminated continually when the alarm is off, the engine is immobilised. The light will flash rapidly to tell you that the alarm has been triggered.
If the light flashes quickly for 10 seconds after the remote control has been used, the battery on the remote control is weak; replace it by opening the back of the remote control and inserting a new battery, positive side up.
Listen for the horn. The horn sounding once when you press the remote-control lock button indicates that the driver's door is not fully shut. The horn will sound numerous times if the alarm has been activated.