Well, recently my alarm has been going off as soon as I turn on the engine.

Does anyone have any idea what's wrong?

It only happens when it is a bit chilly out.

Please help.

Yangster

 

It doesnt do it getting into the car, just once you start the car?

 

Next time check if red alarm indicator LED is blinking or not when you start the car. I notice there is at least one stupid door locking sequence that will arm the alarm after tapping lock switch to lock from the passenger side door while the driver side door is open, then closing the driver side door.

 

It doesnt do it getting into the car, just once you start the car?

Yep, only when I start the car. And only when it's cold out. Usually in the mornings.

 

That's correct. For my case, the factory alarm arms itself unintentionally after locking the doors, then gets into the car and close the driver door. Since the alarm is armed, using the key to start the car will trigger the alarm.

Try this. Open both driver-side and front-passenger-side (FPS) doors. Close the FPS door and toggle the FPS lock switch to lock. All closed doors will lock except the opened driver-side door. Then close the driver-side door (and toggle the driver lock switch to lock) and watch the red alarm LED on the door. It will start blinking after a few seconds indicating that the alarm is now armed. Then try starting the car with the key. Of course, the car won't start but the horn and headlight will be screaming like crazy.

I also notice some combinations of toggling the driver side and passenger side lock switch while the driver or front-passenger doors are open will also arm the factory alarm unintentionally. Mine is a 2002 TL-S. Don't know if this stupid bug is fixed in 2003.

 

I left out one crucial step - don't insert the key and wait. Fixed below.