Your alarm system is to blame for this issue, try disconnecting your alarm from the fuse box and try starting the car again.
The alarm sounded continuously. or The sound of the alarm was continual. Depending on the tense
3 possabilitys integrated alarm system day night sensor on dash neer windshield or disruption in CPU
on your key pad hold the lock and unlock button down until you here the horn sound and lights flash just did it on mine and it work great
For instructions on how to disable a factory alarm, check out the related link below.
Remove the alarm, i did the same in my altima,the alarm box is located under the dash by the steering column, is a little black box, disconnect the terminal and you will be ok.
I have a '03 and there is an alarm if you leave tour lights on.
How to deactivate an anti theft system from a 1995 Nissan altima gxe
Wipers, door locks, lights, alarm if equippedWipers, door locks, lights, alarm if equipped
Check and see if the interior lights come on when you open each door. open one if lights come on shut it and wait for the lights to go off and then open another until you open all the doors. if the lights don't come on with one of the doors it will be a bad door switch on that door. if lights come on on all doors it may be the trunk. check and see if you have a trunk open warning displayed on the information center on the instrument panel. if so the car thinks the trunk is open and alarm won't set.
Are you sure you're setting the alarm and not accidentally hitting the panic button?
In a 2003 Nissan Altima, the alarm fuse is typically marked as "SECURITY" or "ALARM" in the fuse box. The fuse box is located under the dashboard on the driver's side. You can refer to the owner's manual for the exact location and specifications of the fuse related to the alarm system. Always ensure to check the fuse diagram in the fuse box cover for accurate labeling.