2020 Mustang GT alarm problems

[attiladomonkos71]

Hi!

I bought a brand new 2020 Ford Mustang GT in February. Thirty days went by without any problems, I drove 1200 miles. The car was always kept in a dark, safe and locked garage.
After thirty days, the car’s alarm suddenly went off, without any external input (I wasn’t even in the garage). After about 20 seconds the alarm stopped. I noticed that only the siren sounded, without the horn and the hazard lights. This was strange, but I first thought that something triggered the interior alarm. So as an experiment, I rolled down the windows, locked the car with the remote, then moved my hand in the interior. As expected, the alarm went off, but with the horn and the hazard lights (not only the siren, as before).
After a week, the story repeated itself: the siren went off in the locked garage, then 20 sec later it stopped. (Again without the hazard lights and the horn, only the siren). This time I got there faster, so I could see that neither of the information panels showed anything.
I got the advice, that maybe the battery had low voltage, and that caused the alarm. So I measured the voltage, but it was perfect. (The fact, that 30 minutes before the second alarm I had a 100 miles long road trip with the car without any problem, proves that the battery functions well).
I am absolutely clueless, because as mentioned before, the car didn’t give any feedback in connection with the alarms, and I can’t connect the cases to any external circumstances. The alarm system is the default one (which is in every Mustang), I didn’t modify or buy anything to it.
Obviously I went to the Ford salon (Hungary) where I bought my pony, but the dealer couldn’t tell me what the problem could be. Since the problem isn’t something I can show him whenever I want, he couldn’t help.
So I’d be overjoyed if anyone could help me how to solve this problem, perhaps, (if my case is unprecedented) how can I deactivate the alarm system, which is quite useless for me, because I always keep my car in a locked, safe garage, and I never leave my car where it could be stolen.

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[fiveohchris]

Not quite the same case as yours but I also have a new 2020 GT and my alarm triggers at odd times based on how I interact with the keyless entry system.

If I open the door too quickly without first pressing the unlock button on the fob the alarm will go off, and if I open the trunk without first pressing the unlock button the alarm will go off but only sometimes. Did not do this for the first several months. Strange alarm.

 

[Michael_vroomvroom]

Perhaps install the Ford Pass app and connect it to your car? In the "message centre" on the app, it should show when the alarm triggered at least, and may possible also provide some details about why if you are lucky.

E.g., in my message centre I see stuff like alarm triggered due to "vehicle inclination", which was when I was jacking up the car while it was locked. Another is "vehicle intrusion", though the most common is just the generic "unusual activity".

May sound like I have a bunch of alarms, but they're all for good reasons (own stupidity. ;-). No false alarms.

 

[attiladomonkos71]

Thank you very much for your answers.
I am afraid this is something else, because it didn't go off like when someone is trying to break into the vehicle.
But I will defenetly try the Ford Pass.

Thank you again!

 

[Gregs24]

I've had it happen when a moth was trapped in the car.

You can deactivate the internal sensor when you shut down the engine. It pops up on the dash if you have 'ask on exit' enabled in the settings. If that fixes it then at least you know it is the motion sensor inside the car.

 

[ORRadtech]

I can't help specifically with your alarm issue. But, going back to your comments on the battery.
You said the battery voltage was "perfect". What, exactly, was it? You also said that you felt that coming off a 100 mile trip was proof of a good battery. Except it may not be. When the car is running it's operating completely on the car's alternator. The only way to accurately check the battery is to have it fully charged, on a separate charger, then have it load tested. In the US most auto parts stores will load test a battery for free. Maybe in Hungary too?
Anyway, a battery that's getting weak may not exhibit any of the things you've used to seeing. It can still start the car and yet affect the electronics in odd ways. I find it completely plausible that a weak battery could cause what you are experiencing.

 

[M4RC]

I have the same issue, only had the car a month and it’s went of randomly many times with no one even near it.

Battery has been tested and is okay (as it should be for a new car) and there was no flies etc inside.

Very annoying issue.

2021 GT

 

[Gerry_M]

I have the same issue, only had the car a month and it’s went of randomly many times with no one even near it.

Battery has been tested and is okay (as it should be for a new car) and there was no flies etc inside.

Very annoying issue.

2021 GT

I get the same - Feb 2021 built car. Siren goes off randomly and lasts around 20-30 seconds.
I took it into Ford recently for it's first check and they said they couldn't find anything, and I understand it's hard to replicate since it's so random.
In terms of the app, it doesn't log anything like the full alarm does which makes it even harder to trouble shoot.
Really hope someone comes up with a solution for this.

 

[Charlemagne]

Same issue with my new Mach 1, happened to me about 4 times in last 4 months. Siren only. Always happened several hours after I came from a drive. At these temperatures I'm certain there's nothing flying inside. FordPass also doesn't show anything. I'll go to dealer in the spring to check what events diagnostics reads from the memory.

I suspect the car just feels lonely after I leave it...

 

[njweatherman]

Hey guys! I'm not sure this is related or not, but worth a shot.
On my previous 2018 2SS Camaro, it had sensors installed in the hood, trunk and both doors. My hood sensor became faulty and the alarm kept going off. It kept thinking that someone was breaking into my car through the hood.
So, maybe one of the sensors is faulty?

 

[Goblinchaser]

just wondering if anyone has found out a solution to this one. Mines a March 21 and still has the odd alarm being randomly triggered. Similar to above with no nearby alarms, car is garaged and covered. My dealer can’t find any issue. I can live with it as a “quirk” but neighbours not that keen when it goes off in the middle of the night !

 

[erickv354]

I found out my 2019 mustang GT alarm kept going of after I installed the ford pass app. It turns out its the hood sensor

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