Security alarm randomly turns on

Hey GX460USER,

Can I have a bit more information on when the alarm is triggered please?

When you leave the car locked have you monitored it and been able to find the alarm being triggered incorrectly? Does this happen regularly/every time?

Always in the same place or does it happen everywhere?

Does you remote have a panic alarm button?
Are you always in range of the car with the fob when the alarm goes off?

If you keep the key somewhere you could mistakenly hit the panic button this could set it off?

Also a low/fluctuating vehicle or fob battery could cause issues.

Please first ensure you are not activating the alarm with the panic button by mistake and whether being in range with the remote fob makes a difference. If you can monitor the vehicle and see if you notice anything when it goes off. Does one of the doors unlock or anything happen that happens before/at the time?

Hope fully if we can gather a bit more info on the fault conditions we can narrow down the cause.

Regards, Joe

Hey GX460USER,

If it has only been happening since the install of the remote start it may be worth returning to the dealer and asking if they recheck the installation.

If it is a Lexus dealer and they have the dealer diagnosis system they may be able to tell you quickly what has triggered the alarm if the vehicle has a stored trigger history.

This will be the quickest way to check, also the installation of the remote start may be causing an issue.

If one of the fob batteries has not been replaced you could rule that out by changing that too.

Regards, Joe

Since this is a brand new car we need to do two things. First, check for codes using the guide below to help with this:

https://www.2carpros.com/articles/checking-a-service-engine-soon-or-check-engine-light-on-or-flashing

I don't expect there to be codes but we need to make sure. Next we need to rule out foul play. Meaning someone trying to break into it or even a neighborhood kid playing a prank. The best way to do this is park the vehicle in a place that you can set your smart phone up in the window and set the time laps camera on it. You will want to run the charger to it just so it doesn't shut off on in the middle of the night then when it goes off, check the camera to see if someone was around it when it went off.

If there is not, then we need to find out if you live next door to a hospital, fire station, or some other large complex that would put off strong radio frequencies. It is not uncommon for when these facilities do something like turn on a strong CB radio, that it sets off car alarms.

If you do not live near any of these then we need to move the car to different spots and see if this happens no matter where you park it. If it does then we are going to have let the dealer look at it because something in the vehicle is triggering a false alarm. They will need to keep it overnight since this seems to happen at night.

However, it does seem odd that it only happens at night because the vehicle doesn't know it is night time which is why i suspect outside influence.

Let us know what questions you have. Thanks