Car Alarms: Toyota Sienna Car alarm problem, negative cable, toyota sienna

Followup To
Question -
I need HELP. I have a 2000 Toyota Sienna CE 6 Cyl Minivan with over 60,000 miles. This problem involves a factory installed alarm system. I have a perplexing problem and not sure how to diagnose or fix it. Lately, for no reason at all, the factory installed anti theft system (alarm system) sets itself off when the vehicle is parked with the engine off. The lights flash and the horn sounds, I used the remote to turn it off, this used to work, but now the alarm doesn't stay off. I changed the battery in the remote that turns it on and off, but that didn't help. Now, I don't even use the remote to lock or unlock the vehicle, I removed the battery from the remote, lock and unlock the vehicle manually, that way I don't activate the alarm. This worked for a while too. Yesterday, in the middle of the night, With the vehicle alarm off and the doors manually locked, the alarm system activates itself, the lights start flashing and the horn is making a loud racket waking up the neighbors. I quickly put the battery back in the remote, go outside and used it to shut down the alarm, but this was not a permanent solution. As soon as I let go of the button on the remote, a few seconds later the alarm re-activates itself, I had to hold down the unlock button on the remote to turn it off and keep the alarm from coming back on. The only way I could keep the alarm from activating and not disturb my neighbors in the middle of the night was to remove the negative cable from the vehicle battery. This morning, I was going to remove the fuse for the anti theft system, but  I couldn't figure out which one to remove since some of these fuses also deal with other vehicle systems besides the anti theft system. Is there a way to reset or turn off the alarm permanently? Can you help me fix this problem or do I need to take it to the Toyota dealer?

Answer -
   I am going to take a stab at this because
that car's factory alarm arms and
disarms by the remote locking and unlocking
the doors.

I am thinking this may be a dealer installed
car alarm & keyless entry.

try this.
Put the key in the ignition, and turn forward
all the way just before cranking. Then within
5 seconds, locate, press and hold in the
valet/overide button, found under the
dash area, (push button, spring loaded)
until the installed LED (the blinking light)
in your dash area goes on solid,
and the siren chirps once.

(Your valet switch might be the toggle
(on/off) type. in this case, key on,
flip switch in opposite direction,
then turn the key off.)

This should reset the alarm
At this point, the only thing working would
be the keyless entry from the alarm,
if it came equipped that way.

Just Repeat these steps to place it
back to usable armed mode.
You may get 2 chirps, confirming it,
and the lights may flash twice as well.

That should do it.
If you want to remove it at this point,
take it to your neighborhood installer
for this, or buy the wiring chart
(Go to:
for the vehicle, and reverse engineer it wire
by wire, until safely removed.

However, if this is actually the factory
alarm, there really is no way to disarm it,
other then what you have been doing. That
would mean a trip to the local Toyota dealer
would be the next step. They will need
to either reset through the diagostic computer
only at Toyota, of replace it.

Let me know if my way works first.



A Big Thanks to you. You were right, this is a dealer installed system and not a factory unit. I followed your instructions and now the alarm system has reset and the only thing still working is the keyless entry. With the obvious reason of not having an active alarm system, is there any reason that I can't just leave the alarm disabled and just use the keyless entry? Do you think the alarm control unit going bad and in need of replacement or is there a fuse somewhere needing replacement?
Thanks Again

Glad to help Frank. There is no reason you can't just
leave it this way except that it is not an alarm system
any longer in this state. It's possible that the alarm
was set off, and required you to physically reset
as you did. But if happy with this result as is,
then leave it be. Your keyless will work as before.

Your call really, but if it were me, I'd try to
go back into armed mode, (Just repeat the steps
you used to go into valet to get out of it)
and if it still gives falsing triggers, then yes,
go into valet again, then replace the system
entirely for one you know.

Good luck which ever way you go with it.