My nissans alarm is set by the drivers door. my key dont unlock the door how can i reset it so i can drive it? my car wont start

Unlocking the car using the drivers door key cylinder will disarm the factory alarm.

ON NISSAN MANUALLY LOCK ALL DOORS THEN UNLOCK THE PASSENGER DOOR WITH THE KEY THEN THE DRIVER DOOR THEN PRESS AND HOLD THE BRAKE PUT KEY IN IGNITION THE CAR SHOULD START NOW THIS RESETS THE ALARM

what occurred is that the theft module has reset
typically this only occurs with after market systems but I've seen it a few times with the factory system too

assuming you have the factory alarm key fobs
try locking and then unlocking all doors

open and close the passenger door
open the drivers door
close passenger door
close drivers door
try to start the vehicle

if vehicle still will not start then you will need a professional scan tool to reprogram the keys and computer

you need to reset alarm/immobiliser.lock car with remote, hold button down for 30 secs,then press/hold down unlock button,should reset.another way is with key in ignition/turned on, press alarm button down and hold for 30 secs.this resets immobiliser.toyota
systems vary..depending on market.

go to your pass side door and with the battery connected and lock and unlock the car with the key till the alarm turns off from the pass side

now you know what sets off the nissan alarm.lock the car,with the key, hold key over for 30secs then unlock with remote.should reset system....you unlocked the car manually so you need to lock the car manually....

this is how most nissans program the key fobs.
get in the car and manually lock the drivers door with the door switch.
put the key in and out of the ignition about 10 or 12 times until the hazard lights flash once.
turn the key to the ignition setting so all the dash lights are on,but do not start the car.
click the lock button on the remote fob.the hazards should flash once to confirm.
turn off ignition and remove the key.
unlock the drivers door and open the door.
the remote should now work.
if that does not work,the dealer can reprogram the fob with the obd diagnostic system.

use the key to unlock the trunk and that cancels the alarm.

use the key and unlock the trunk...if that doesnt work do the passenger door...that should reset the alarm...

The ignition security on/off is located at the trunk lock. unlock and lock rear gate and the alarm will turn off. My jeep sat in my drive for a month before a jeep tech told me this. It still triggers the security sometimes when I unlock the passenger door with the key and I go straight to the rear gate lock and it shuts off instantly.