Little background first, I have had a 1993 SSEi for about 8 months now, and it does not have an aftermarket alarm system installed.

Three days ago I had just came out from a store and unlocked my car doors and to my surprise an alarm started going off (headlights flashing, horn honking). The car would still start and was driveable while the alarm was going off. The alarm stopped after what seemed like a couple of minutes. I arrived home, opened the door, and the alarm started going off again (stopping after approximately one minute).

Well I used the car today (first time since) and everything is fine. I asked my mechanic about it and he thinks it may be something to do with the factory security system, related to the door locks, but that I would have to take the car to a dealer for them to check it. I was just wondering if anyone has experienced this before, or has any ideas what it could be? Thanks in advance.

I remember a similar experience a while back with my 92. I can't remember what the "trigger" so to speak was, but all I did was put the key into the driver'* side door and lock it. Once I did that the alarm went off and I haven't had a problem since.

Is it possible you used the key fob to lock the doors, and then used the key to unlock it after? That will definitly trigger the alarm.

How about pulling the fuse to disable the alarm?

I don't have a key fob or keyless entry system, so it is still a bit of a mystery why it went off originally. I've just been using the key to lock and unlock it since then (not using the power door locks) and everything has been okay for now. Thanks for your help.

Check over any grounds and clean them. Was it wet or damp that day?