Car Alarms: Lexus IS200 security system, lexus is200, alarmtek

Question
QUESTION: After 'arming' the security system and locking the car with the key fob, the alarm goes off after a few minutes.
I am getting around this at the moment by manually locking all of the doors (therefore not arming the system). Three days later and this old school method of locking my car is beginning to annoy me!
Any thoughts?

ANSWER: Please be more descriptive if possible.

"GOING OFF?"

I need to determine whether it's a factory alarm
issue or, if it's an aftermarket system you are
dealing with.

Is it: Headlights flashing, car horn honking
and a worded SECURITY" light in the dash flashing?
(doubtfull since none of the notes show this
car as having a factory alarm system)=FACTORY

Or,

is it: flashing parking lights,
an LED in the dash area, and a siren
going off?= AFTER MARKET

Let me know more on this to better
advise you on a course of action
to take.

Best Regards,

Robert Martin
CEO/ALARMTEK
CARALARMMAN.com

---------- FOLLOW-UP ----------

QUESTION: This is definitely a factory fitted alarm system.

Answer
Well, ok...Lexus security systems detect battery drain when a light
is left on, or a circuit left energised. This usuall means
a door/dome light is on, possibly a trunk (boot) light.

Short of this situation, a broken or damaged key switch in the doors
can also be the culprit. If batt drain is detected,
the Lexus would flash it's head lights and honk it's horn
when armed reporting a breach.

After market would involve a siren and parking lights.

The original key fob or even the addition
of an after market system with door lock functions
would take over for the factory system, but would also depend
on door triggers, with the addition of a shock sensor.

But then it's after market and has a way of changing how
it reports, not so much with a factory system.

The factroy system depends on the door locks opening and closing
to arm and disarm. My guess is if factory, you have an open
circuit to detect and tamp down.

A.