Alarm goes off non stop when I lock the car… anyone know why?

Seeking Help
1

Hi folks!
I’m having a problem with my 2015 Focus MK3. One night, the alarm went off by itself (I was standing next to the car), and it keeps going off every time I lock the car using the remote or when I arm it from inside with the ‘alarm key’ (and the doors stay unlocked).

Here’s what happens: I lock the car with the remote, it makes the usual two chimes, then I get 5 quick beeps (they sound different from the usual chimes). After about 10 seconds, the alarm goes off.

The only way I can lock the car without the alarm going off is by using the physical key.

Also, every time I unlock the car, I get the same two chimes and 5 beeps.

2

You can use ForScan to check which sensor is causing the alarm. Once you find the bad sensor, replace it and you should be good to go.

3

Chen said:
You can use ForScan to check which sensor is causing the alarm. Once you find the bad sensor, replace it and you should be good to go.

I tried using ForScan, but it doesn’t even show that an alarm event happened. The only thing I noticed is:
HOOD_SW - Hood Ajar Switch: On
But I’m not sure what the default state should be.

4

@Abi
If no other codes pop up, it could mean that the hood latch sensor is loose or faulty. This happens often and is easy to fix. I’ve had it happen on my Focus and Fiesta. The 5 beeps are a bit odd though, they usually point to an airbag issue?

5

@Chen
It looks like the problem is coming from an aftermarket alarm system, but those 5 beeps seem to mean that something is not closed properly (even though it is). It might be the hood latch sensor, but I don’t see one plugged into the mechanism, and the car doesn’t say the hood is open even when it actually is…

6

I bet there’s an aftermarket remote start or alarm that’s causing this. There’s no way the factory system would trigger 5 beeps like that. It sounds like something like a Viper remote start system.

7

Cedar said:
I bet there’s an aftermarket remote start or alarm that’s causing this. There’s no way the factory system would trigger 5 beeps like that. It sounds like something like a Viper remote start system.

Nope, there’s no aftermarket alarm system, and the car doesn’t have remote start. To be more exact, it’s not 5 honks, it’s 5 beeps.

8

@Abi
What you mean is there’s no remote start or aftermarket alarm that you know of. But what do you mean by ‘alarm key’? That doesn’t make sense to me.

9

Cedar said:
@Abi
What you mean is there’s no remote start or aftermarket alarm that you know of. But what do you mean by ‘alarm key’? That doesn’t make sense to me.

Here’s a picture of the small key I mean (it looks pretty much the same): CHIAVE ELETTRONICA EMERGENZA GT AUTO ALARM 969 CH GT969CH sblocco allarme antifurti linea gt900 gt969 : Amazon.it: Auto e Moto. It’s a two-pin ‘contact’ near the transmission that I touch with the key to manually turn the alarm on or off from inside the car.

10

@Abi
Okay, so this is an aftermarket alarm, exactly what I thought.

11

Cedar said:
@Abi
Okay, so this is an aftermarket alarm, exactly what I thought.

Oh, okay, I had no idea. I bought the car used from a dealership and assumed it was stock (the dealer didn’t mention anything about it).

12

@Abi
You need to find out what brand and model it is. Maybe there’s a logo on the key? The 5 beeps are likely an error code specific to that unit.

13

Cedar said:
@Abi
You need to find out what brand and model it is. Maybe there’s a logo on the key? The 5 beeps are likely an error code specific to that unit.

I found out the brand is GT Alarm, but there’s not much documentation online. I found a forum post saying that 5 beeps means something’s not closed, which brings up another issue. Everyone mentions the bad hood latch sensor, but mine doesn’t even have one plugged into the hood latch, and the car doesn’t indicate if the hood is open even when it is. So yeah, I’ve got a few things to figure out…

14

Cedar said:
@Abi
You need to find out what brand and model it is. Maybe there’s a logo on the key? The 5 beeps are likely an error code specific to that unit.

Thanks again, you’ve been super helpful!

15

@Abi
No problem!