Weird issue with anti-theft system

[Books]

Just started having this weird issue with my 2005 Mazda 3 GT the other day. I went to open my door after remotely unlocking them and the alarm went off when I opened it. After a few minutes and powers of deduction, I figured out that the car is turning on the anti-theft IMMEDIATELY after unlocking the doors. It also enables it when I close my door and other random times. It was actually doing it while I was driving.

I'm not sure what's causing it so I wonder if you guys have any ideas (before taking it to get checked out) as to the cause - maybe wiring, fuse, etc.

Cheers,

[silverstarmazda]

close all the doors and lock and unlock them a couple times.

[silverstarmazda]

i had this confused car problem before. did u lock the car with one door open (before passenger can close it). i forgot how you do it exactly but i think locking and unlocking a couple times straightens out any confusions ur car has

[Books]

Interesting. You mean, unlock and lock once each and repeat? Or unlock, lock x 2 (to get horn beep) and then repeat. I'll go try this outside now when you let me know.

[DTK]

Interesting. You mean, unlock and lock once each and repeat? Or unlock, lock x 2 (to get horn beep) and then repeat. I'll go try this outside now when you let me know.

I had this problem a few days ago. I just locked/unlocked the car again and it was fine.

[silverstarmazda]

lol i dunno, just close all the doors properly. then lock and unlock the car a couple times

[silverstarmazda]

last time it happened to me my alram was super sensitive as hell.... then again just might be cuz the car thought opening the car was still locked

[Books]

But what's happening is that as soon as I unlock the car with the remote, the instant right after, it engages the alarm. So the doors are unlocked but as soon as I open any door, the alarm goes off. What do you think now?

[silverstarmazda]

that is....rly weird....nvr heard of anything like that before....lock it till it beeps and unlocking it will still set it off?

[silverstarmazda]

might as well take it in just in case... and ask if theres any recalls lately

[McGuyver_3]

if the horn beeps then the locking system of the unit(BCM aka PJB) is working properly. Sounds more like you are having an issue with your anti theft system. This system runs through your PJB, cluster, car computer (ecu) and your key. I am sure the alarm system is tied in to it one way or another but I would be more so under the impression it is an output from the immobilizer system. You may have no choice in this situation but to take it to the dealer