2013 C7 A7 Alarm goes off randomly when parked

[Chen5441]

Hey guys, I have just purchased a used 2013 c7 a7 with about 94,000 miles. This is my first Audi. So far everything has been perfect aside from having a blown bose driver door woofer everything is great as far as I can tell. However, I am having this issue with my alarm. I will park the car, lock it, and walk away from it and sometimes the alarm will go off by itself. Sometimes it's just the lights without the siren. One time I shut the alarm off and it preceded to go off another 2 times before I could even get inside. It's becoming annoying for both my neighbors and I. Has anyone had this issue or know what it can/might be?

[15 Phantom S6]

I've had this problem on another platform but I think it's the same as what you're experiencing. IT could be one of 2 things;

1) there is a rechargeable battery within your alarm siren (not horn). The battery goes bad and makes the alarm go off at random times. Sometimes battery cannot recharge, sometimes the battery has leaked on the circuit board, both reasons make the alarm come on randomly. Usually the siren is sealed and you can either dremel it open and replace the battery (if you can find the right one) or you can just replace the entire siren altogether..

2) One of your door sensors are finicky and when your car is "armed" the sensor is faulty and thinks or signals to the ECU that the car door/trunk/hood is open, so your alarm goes off. This one is harder to diagnose since you don't know which sensor is the culprit..