[Meccagrey]

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.

 

[BDM]

Had the exact same probelm.

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

Part # 53510-08041
Descrition Lock Assy , Hood.

 

[Narboza]

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.

 

[Evil-Sienna]

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?

 

[Narboza]

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.

 

[Evil-Sienna]

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?

 

[Narboza]

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?

The alarm works the same as tens of millions of other systems from multiple manufacturers. Aftermarket alarms work with the base alarm to add additional features (lights, auto arm, start, longer range remote, etc.) but the base features cannot be removed since that is in itself a security feature. Have the dealer check this TSB.
T-SB-0171-11 Security Alarm False Activation

Introduction

Some 2011 Siennas equipped with a factory theft deterrent system may exhibit a condition where the security horn is inappropriately triggered when the vehicle has not been disturbed. A revised hood latch assembly (with internal component switch) has been made available to address this condition.

Production Change Information

This TSB applies to all 2011 Sienna vehicles produced BEFORE the Production Change Effective VINs shown below.

1AR 2WD 5TDKA3DC#BS006695
2GR 2WD 5TD#K3DC#BS117781
2GR 4WD 5TD#K3DC#BS019247

 

[ArtKuip]

Thanks for all your suggestions and ideas in this thread. I have experienced all the frustrations mentioned here. My 2011 Sienna XLE alarm goes off randomly sometimes as long as 4-5 hours after the car is parked in the driveway. It's a real pain especially at night. I will take your notes regarding the Hood Latch solution to the dealer and see what happens.

 

[mwrobison]

Had the same issue as everyone above, and the hood latch replacement was the fix. Toyota knows of the problem, and has known since 10/28/11. Go to a Toyota dealer parts desk and ask them about Technical Service Bulletin: T-SB-0171-11. To me, there should have been a recall. Because mine didn't exhibit the problem until 75k miles, I got stuck paying for the replacement of their KNOWN defective part. I also spent a month as the pariah of the neighborhood, as my alarm kept going off in the middle of the night. The part costs about $85, and unless you are willing to do the labor yourself, it will probably cost you another $100+ to have it installed. The part number is 53510-08041. Replacing the part isn't too bad. Pop the grill off first (there are six plastic pop rivets you have to *carefully* pull up). Then remove the three 10mm screws that secure the latch to the car, one of which is covered with a cap (just use a screwdriver to dig it out). Disconnect the release cable and the alarm switch, and it's out. Reverse the process for the install. Takes about 20 - 30 min.

* Didn't notice "page 2" of the posts until after I wrote my reply. I think it still has value though, so I will leave it.

 

[billmac]

Thanks for the informative post mwrobison.

 

[civilian]

Apparently this fix will also correct my false activations. Sometimes many hours after shutting off the vehicle. Happened tonight again. Nothing around it to have caused it to activate. Will have to call dealer tomorrow as it has 58, 600 mi and is racking up another 1500 miles this weekend. I don't really want to have to pay for it.

 

[kyoung0645]

I just purchased a 2011 Toyota Sienna and started having the same alarm issues, randomingly going off with no pattens. I have ordered a new hood latch and am going to see if my husband can install it. I called Toyota and gave them the service bulletin number referenced by Narboza and they confirmed the issue. If this works, it will surely save me a lot of embarassment at the office. Everyone here knows its just my car going off when they hear the constant honking. Thank you Narboza for your help!

 

[afinngirl]

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.

 

[moriahjes]

Same here . Was there a recall for this problem ?

 

[jaking]

Had the same issue as everyone above, and the hood latch replacement was the fix. Toyota knows of the problem, and has known since 10/28/11. Go to a Toyota dealer parts desk and ask them about Technical Service Bulletin: T-SB-0171-11. To me, there should have been a recall. Because mine didn't exhibit the problem until 75k miles, I got stuck paying for the replacement of their KNOWN defective part. I also spent a month as the pariah of the neighborhood, as my alarm kept going off in the middle of the night. The part costs about $85, and unless you are willing to do the labor yourself, it will probably cost you another $100+ to have it installed. The part number is 53510-08041. Replacing the part isn't too bad. Pop the grill off first (there are six plastic pop rivets you have to carefully pull up). Then remove the three 10mm screws that secure the latch to the car, one of which is covered with a cap (just use a screwdriver to dig it out). Disconnect the release cable and the alarm switch, and it's out. Reverse the process for the install. Takes about 20 - 30 min.

* Didn't notice "page 2" of the posts until after I wrote my reply. I think it still has value though, so I will leave it.

Thank you so much for this information! Bought a replacement hood latch off Ebay and installed it in about 10 minutes. The information you provided was better that anything I could find from Toyota so I really appreciate your post! Thank you!

 

[alu85719]

Tuviste solución?

 

[ealidost]

I just purchased a 2011 Toyota Sienna and started having the same alarm issues, randomingly going off with no pattens. I have ordered a new hood latch and am going to see if my husband can install it. I called Toyota and gave them the service bulletin number referenced by Narboza and they confirmed the issue. If this works, it will surely save me a lot of embarassment at the office. Everyone here knows its just my car going off when they hear the constant honking. Thank you Narboza for your help!

Did the new hood latch oem part fix the issue? I have the same issue, I put an aftermarket part but problem is not solved.