Factory alarm intermittently going off / Possibly hood lock/latch switch?

[gtme]

My factory alarm on my 2013 LC200 started randomly going off in the middle of the night, neighbors loved it . Has anyone else had this issue? I check all the doors and they are locking fine, checked the key fob, good too.

One thing I found is that if I open the hood, leave it unlatched, then lock the doors like normal the alarm doesn't go off. I'm thinking it might be the switch in the hood latch. Any thoughts?

Also, anyone on here ever removed their hood latch/lock? Doesn't look like the removal process is the normal remove grill and then 3 bolts I have seen on other Toyota's, it's a bit buried.

 

[GoISU]

Man that sounds like a real pain. I’ve never triggered my alarm but I would be curious what the features of the factory system are. If I recall, it uses a microphone in the cabin to listen for breaking glass? If I reach in and unlock a door with the windows open I assume the alarm will go off as well? I’ve never had an activation to my knowledge, not even in the wind. Anyone have any details?

 

[NHouston]

Mine was doing the same thing. Are you interior lights coming on at random when you drive? My rear hatch actuator was bad. It has a built in sensor that went bad. Part is listed on my build thread “The Mall Crusher”

 

[gtme]

I haven’t noticed the lights coming on while driving but I’ll watch for it. Thanks for the suggestion on the rear hatch actuator I’ll take a look at it.

Toyota dealer I took it to was clueless, they didn’t see anything in their diagnostics and didn’t know where to start.

 

[UCrazyKid]

I had a few mysterious times the alarm went off. I changed the battery in my key fob and the problem did not return. I have no idea if this is actually what fixed the problem.

 

[gtme]

Ended up changing out the hood latch/lock today and thought I was good, but alarm ended up going off 8 hours later. Not sure where to go from here. I also replaced my key fob battery, but unfortunately didn't do the trick.

Toyota dealer says they have no way to diagnose it, to figure out where the issue is. Is that true?

 

[JPRS]

Ended up changing out the hood latch/lock today and thought I was good, but alarm ended up going off 8 hours later. Not sure where to go from here. I also replaced my key fob battery, but unfortunately didn't do the trick.

Toyota dealer says they have no way to diagnose it, to figure out where the issue is. Is that true?

I had a similar alarm issue that developed with my 2018 LC over this past year. I use faraday pouches for my LC keys so I knew I was not accidentally setting off the alarm by pressing the alarm button while in my pocket. I had a few visits to the dealership over the past several months about the problem in an effort to diagnose and fix the issue. Of course, the alarm would never go off at the dealership to allow them to see the problem for themselves.

First, we changed out the battery--thinking that maybe since the vehicle has been sitting inactive for longer periods due to working from home during COVID-19, the alarm functions were somehow being thrown off. But, within a few weeks later it become apparent the battery was not the issue. I asked the dealership to see if there was a glass sensitivity setting which could be reduced, but the dealership told me there is no such setting on LCs. Note that I had to have the windshield replaced a couple months after brand new, and although the alarm was not an issue for a couple years following the windshield replacement, it's possible that the windshield replacement somehow led to sensors being more sensitive then they need to be.

Nevertheless, after a few visits the dealership decided to replace the hood latch sensor (my truck is still under warranty), and I was told that while working on this, one of the more experienced dealership technicians looked at the truck and knew that sometimes the Toyota personnel (located at the "port" into which the truck arrived from Japan) install additional accessories, including an alarm sensitivity instrument. The port into which this truck was shipped was the Houston port. Anyway, this technician was able to find this sensitivity instrument just behind the glove box and see that it was set to a "3" on a scale of 1 to 10. The technician changed the setting to "1" instead of "3." Now I don't know whether the hood latch sensor or the alarm sensitivity setting was the issue, but so far (after a few weeks) I have not had any issues with the alarm. I will repost if I later have issues.

Here's a photo of the sensitivity instrument supposedly installed at the port in Houston:

 

[biphnest]

That looks like a dealer added device. Toyota should not allow dealers to hack up brand new vehicles with their add on security devices without the customer’s consent.