Bring it back to the dealership until they figure it out. It's under warranty. They need to fix it.

 

I would have to agree that the dealership should be able to find this one. If it is reasonably repeatable, then you have a good case and should press them on the issue.

Now, from a strictly troubleshooting aspect, you might arm the system, then go around and push/pull/ or otherwise aggravate various switches which might be "hair-triggered". For instance, try pushing on the hood(without opening it) and see if that immediately sets off the alarm. Or push/pull on each door. You get the idea.

And perhaps the shop can pull alarm codes? Seems like there should be some codes telling which component set off the alarm.

 

I would have to agree that the dealership should be able to find this one. If it is reasonably repeatable, then you have a good case and should press them on the issue.

Now, from a strictly troubleshooting aspect, you might arm the system, then go around and push/pull/ or otherwise aggravate various switches which might be "hair-triggered". For instance, try pushing on the hood(without opening it) and see if that immediately sets off the alarm. Or push/pull on each door. You get the idea.

And perhaps the shop can pull alarm codes? Seems like there should be some codes telling which component set off the alarm.

All good ideas. I'd also ask myself the question: what else happens ten minutes after the car is parked? And that would make me suspicious of a door sensor: isn't that the interval at which the interior lights will time out if you leave a door open? So if a door sensor is allowing the alarm to arm but then when the timeout happens, is showing the door open for some reason, woop woop woop...

If the dealer keeps pushing back, I'd start muttering "lemon law" under my breath, and ask for the area rep to get involved. They can't just throw up their hands.

 

I believe the interior lights time out at 20 minutes if the door is left open.
Bob

 

This brings up an important point. Repeatability. IF you can find some pattern to the false alarms it could provide some keys to the root cause. A really important pattern would be a time from lock to false alarm. If the alarm consistently goes off "X" amount of minutes then that is very useful info. If random, then that tells you its not a timed setting of a computer. Get a stopwatch (or similar down to the seconds) and begin experimenting.

Try a different dealer if one of them is stumped.

 

Thank you all for your replies!!! I'm going to do the door/hood-sensor test after, followed by the stop watch test. I'll post back results. If all fails, I'm going to another dealership next week.

 

Going to the dealership.... I checked all doors and no issue there.

When I experience the horn/alarm problem, there is only 1 beep and flash of lights upon locking. When I lock the door and get 2 beeps and flash of lights, there is no problem. However, I can't make it beep 2 times....I get what I get. Ughhhhh ???

 

Going to the dealership.... I checked all doors and no issue there.

When I experience the horn/alarm problem, there is only 1 beep and flash of lights upon locking. When I lock the door and get 2 beeps and flash of lights, there is no problem. However, I can't make it beep 2 times....I get what I get. Ughhhhh ???

I'm 99.44% sure I only ever get one beep/flash on lock. I get two on UNlock. Every Toyota I've ever driven was like that, and it's mnemonic: LOCK has 1 syllable, UNLOCK has two (not that it's exactly tricky to remember anyway...).

 

I experienced this while out camping at Yosemite. At first, I couldn't figure out how to disable it, so it was a harrowing experience waiting for it to go-off again and again and again. It was the housekeeping site and there were a bunch of campfire smoke going, so I guess this is one of the reasons.

 

This is also happening to our 2011 Toyota Sienna, alarm goes off all the time, after locking it.

I also brought it to a Toyota Dealer last week in Brockton, MA - Waiting 90 minutes for them to say they couldn't find anything wrong with it.

It is driving us crazy. As we watch our kids play lacrosse and the alarm goes off 3 times during the course of the game.

We need HELP!!!!

 

Same here!! Horrified during baseball games...keep happening...harrowing and embarrassing. This sounds like a recall issue.

 

Yep....sometimes my sienna locks with 2 beeps and sometimes with 1 beep. It's so random. The underlying cause is unknown. 1st dealership in Dalton GA couldn't figure it out. I'm gonna call service dept in Chattanooga and see what they know.... The manual says 1 beep for lock.....Houston we have a problem. Today, it locked with 1 beep and then 2 hrs later the alarm/horn sounded. :-\

 

According to the New Car Features document:

The system switches to the alarm state when one of the following conditions is met.

• With all doors closed, the engine hood, or back door is opened.
• With all doors locked, any door is unlocked by a method other than the mechanical key, door control transmitter, or key.
• A terminal is disconnected from the battery and reconnected.

First, I would check for a battery problem (bad cell or bad terminal connection). Second, I would look at the hood switch and check that its alignment is correct and that it works properly.

 

I think the problem is probably the hood switch neg trigger. It's set too sensitive or barely disconnect.
First the engine compartment is hot, when hot mater expand. In this case the switch expand and fully disconnect the switch.
few hrs later engine compartment cool down and mater shrink. The switch shrink and make a contact which trigger the alarm.

just my 2c

 

I think the problem is probably the hood switch neg trigger. It's set too sensitive or barely disconnect.
First the engine compartment is hot, when hot mater expand. In this case the switch expand and fully disconnect the switch.
few hrs later engine compartment cool down and mater shrink. The switch shrink and make a contact which trigger the alarm.

just my 2c

we had the random alarm going off issue and they root caused it to be a defective hood latch trigger. Here's the service note:

TRIM ELECT CONCERN ~|~COMPLAINS THAT ALARM RANDOMLY GOES OFF AFTER APPROXIMATELY 1 HOUR AFTER BEING SET ~|~ALARM IS GOING OFF AT RANDOM TIMES--INTERNAL FAILURE IN THE HOOD SWITCH ~|~REPLACED HOOT LATCH/SWITCH AND RECHECKED OK NO MORE PROBLEMS 530111 .5

 

Thank you so much. I'm going to take the an to drl in the morning. Now I have some potential solutions!!!!!

 

Going to the dealership.... I checked all doors and no issue there.

When I experience the horn/alarm problem, there is only 1 beep and flash of lights upon locking. When I lock the door and get 2 beeps and flash of lights, there is no problem. However, I can't make it beep 2 times....I get what I get. Ughhhhh ???

I cant help but wonder if when you get the 2 beeps the system is disarmed like when you unlock it? So naturally the alarm will not go off because it is not set. Have you actually verified that the doors are indeed locked and the alarm armed when you get the 2 beeps?

 

I cant help but wonder if when you get the 2 beeps the system is disarmed like when you unlock it? So naturally the alarm will not go off because it is not set. Have you actually verified that the doors are indeed locked and the alarm armed when you get the 2 beeps?

Wow, what you wrote is almost word-for-word what I was about to write! GMTA... ;D

 

Well.....yesterday I took the van to Chattanooga DRL. With a list of solutions you all recommended. They supposedly checked everything and had the van 9 hrs, but could not get the horn to go off or locks to double beep. Uggggh. First of all, I will never return to Capital Toyota cause they did NOT check the battery or hood. I know this because none of my radio stations were impacted, which would happened if they disconnected the battery and today I'm back to 2 beeps upon locking.

It's just a mater of time till the horn/alarm sounds..... The only good thing I have going is that all of this is documented. So, if a solution is later found I'll still be covered/grandfathered. :-[

 

...and you double checked to see that when you get 2 beeps, the doors are actually locked? Because if they are not, then something weird is going on with the computer.

In the meanwhile, you can do this little trick to lock the van without the alarm going off (maybe you already do). Press the drivers door electric lock down or use the key fob to lock all of the doors. Then press the unlock one time only. This will unlock the drivers door and disarm the alarm system. Then open the drivers door and manually lock the drivers door. Its a pain but will get your van locked w/o the alarm going off.

 

When I get 2 beeps all doors are locked and alarm is armed, but it never sounds off in error.
When I get 1 beep, sometimes the alarm goes off.
Currently, it is locking with 1 beep, armed and no sound off. Thank God! However, I'm still looking for potential solutions as it is just a mater of time.....
Thanks for the inside door lock suggestion, but I have tried this too.
What I think worked once was locking with fob, unlock with fob and then let it lock itself.

 

Had the exact same probelm.

Dealer replaced Hood Latch as the latch was not engaging properly.

Part # 53510-08041
Descrition Lock Assy , Hood.

 

This problem is now addressed in a TSB under the standard warranty.

T-SB-0171-11: 2011 Sienna Security Alarm False Activation

They redesigned the hood switch.

 

Hi all, i have a 2011 XLE AWD Sienna and recently I have been experiencing the same problem. But i've only experienced this by my house where my van is parked. When i go out and park elsewhere, i never experience it going off. I am planning on bringing it back to the dealer and tell them of issues and suggest the hood latch.

Until then, is there a way to turn off the alarm but able to lock the doors with the remote? I found a button under the dash, i think its to manually turn off the alarm with ignition key or is it a valet switch?

 

Until then, is there a way to turn off the alarm but able to lock the doors with the remote? I found a button under the dash, i think its to manually turn off the alarm with ignition key or is it a valet switch?

No. The button is the Tire Pressure Warning Switch to set/reset the normal pressure for the system. The alarm system is built into the Body ECU and is always on. You may have the problem at home depending on how the frame is stressed.

 

Actually, for the 1st time, the alarm went off after 5-10min parked while away from home yesturday. I was thinking there might be some weird frequency causing it, but i doubt it now. Either way, i have to bring it to the dealer to have it looked at. I just feel the dealer is going to say, there isnt anything wrong....

Why wouldnt my sienna have a valet switch option? What if I wanted to get rid of it and get an aftermarket alarm later on?