Horn honking when locking and unlocking doors

Apologies if this has been answered elsewhere already...

I have a 2010 Prius IV and set the doors to all unlock when I touched the driver's door handle. Annoyingly, now when I touch the raised spot on the handle (either driver or passenger side) to lock all the doors the car does the beep but also briefly toots the horn. The horn also toots when I touch the handle to unlock.

My old 2005 Prius VI just did the beeping (which my neighbors and I can live with) but the addition of a honking horn, however brief, is pretty annoying. I can't seem to find a place to disable this unwanted feature... little help?

 

I'm not sure--- I did the 2-button keyfob press on the lot before I even sat in it since I knew beforehand that it defaulted to opening just the driver's door on touching the handle. I thought I had done my research and due diligence but assumed I missed something that was making the horn honk along with the familiar beep.

 

I tried switching back and forth between unlock modes but either way the horn toots briefly. So I take it this is not normal behavior... when I go in for my next oil change I'll ask them to look into it.

I had intended to keep my 2005 Prius until the 4th-gen was released but a semi ran me off the highway and reliable old silver was totaled at 153,000 miles. I only got the 2010 as an interim car and found the horn thing to be a bit obnoxious. Other than that, the lack of interior storage space (compared to 2nd-Gen), and the absence of a display for the average mpg on a tank of gas, so far it's actually nicer than I thought it would be.

 

Thanks for the alarm ideas--- there is a little mystery gizmo under the dash just inside the driver's-side door with a blue light on the front. I reached under it and it does have a button to depress (which I did numerous times in varying combinations but there was no change in horn behavior) so at some point this week I plan to take it to my car guy and see if it's one he's familiar with.

RRxing: Yeah, saw that. I just liked the convenience of having the display always there and having it automatically reset when I added gas to the tank. Your point is well-taken, though... maybe I'll get into the manual reset habit eventually.

Thanks again for the suggestions!

 

Nah, no specific charge for it. I got the car used after my 2005 was totaled. I had intended to skip the 3rd-gen Prius and get a 4th-gen as my next car but a careless semi driver decided otherwise for me

If it's a common brand/model alarm though, I am hopeful that I can get that maddening honking disabled ASAP.

 

And the offending device removed and all is well in the world! Thanks, all.