Car Alarm Keeps Going Off: Causes and How To Fix It ?

Car alarm installations are necessary security steps to prevent potential thefts. There are a few cases where the car alarm keeps going off, without any threat in sight (someone trying to break in). This issue may seem pretty startling but keep calm, as there are various reasons why the car alarm keeps going off.

Still, it is pretty essential to fix this issue quickly to avoid listening to that annoying sound all day long. Ever wondered about the car alarm going off in the middle of the night in the UK or the US? Such an incident may attract some penalties from the authorities, much more if those within the neighborhood can’t get enough sleep.

Remember, the alarm is set to go off when someone tries to steal the car. Nevertheless, a faulty installation or even a low battery charge can cause the alarm to go off randomly. So, knowing how to turn off the alarm system of your Hyundai or Toyota would be great.

What Causes Car Alarm Keeps Going Off? 

It is right for car owners to install anti-theft car alarms for securing their vehicles. The alarm often goes off when someone tries to steal the car. Before learning why the alarm goes off falsely, it would be beneficial to understand how the alarm works.

how do i stop my car alarm from going off randomly

The alarm system consists of four basic parts:

  • The sensors
  • Keycode receiver
  • Computer
  • Loudspeaker

There are a variety of sensors, such as impact/shock sensors, impact sensors, door sensors, microphone sensors, and tilt sensors. With the sensors in place, they receive any unusual signal and give off an alert from the loudspeaker.

In essence, a faulty sensor would cause the system to give off sound falsely. Nevertheless, it may seem challenging to pinpoint the actual cause of this problem, since no definite cause exists. So, if you notice the car alarm going off while driving, here are some possible reasons.

Read Also: How to Program a Transponder Key Without Original?

Bad Battery

If the car has a faulty, dirty, or corroded battery, it may send wrong signals to the alarm system. The same applies to vehicle battery terminals that appear worn or rusty. Not only does this causes unrest in the alarm system, but it could also cause some electrical malfunctioning in the car.

Faulty Key Fob

The key chain or fob works as the electric remote of most cars, especially modern vehicles. Thus, it works well in locking and unlocking the car’s door. In many cases, you can comfortably start the engine using this key fob. Still, it works effectively for setting up the alarm and preventing possible theft.

Bad Hood Latch Sensor 

With the effective way the alarm system works, the noise goes off when folks try to lift the hood. You can find this hood latch sensor in many modern cars and based on the car’s condition, the location of the sensor may soon be a place accumulated with dirt, dust, and grime.  

Thus, there would be an issue of the signal becoming inconsistent if you don’t locate and clean the sensor. The hood latch sensor is often situated inside the hood lock; so, find it and get it cleaned. While doing this, it would help if you handle the hood latch sensor with care, to prevent any damages.

Aside from this, there may be some issues with the installation of this security component, causing a malfunction. Perhaps there is a loose wire, leading to a poor connection. Hence, you may experience such a false alarm until you get this issue fixed.

Faulty Alarm Module

The car alarms that come with most vehicles are of great quality, as the manufacturer of the car ensures they have an integrated control unit alongside the primary electronic control unit. In essence, you can rarely find issues of a faulty alarm module with such alarms.

Nevertheless, replacing the original alarm system that came with your car, may pose some problems for you. Most aftermarket alarms for vehicles come with a control module, which handles all switches and sensors. If the control module goes bad, all other components begin to malfunction.

Damaged Door Lock Sensor

The door latch sensor goes off when someone tries to open the car of your vehicle forcefully. Such sensors come with two wires, which could cause a false alarm to go off if damaged. Nevertheless, you can test them with a multimeter, to ascertain if they are in good shape.

Finding the location of your car’s door latch may seem pretty challenging. Some get installed externally, while others get installed inside the look actuator of the vehicle. Still, you need to find the sensor to help solve this issue.

Read Also: How to Reset car radio Without Code

What Should We Do If Car Alarm Keeps Going Off? 

How do I stop my car alarm from going off randomly? Why won’t the car alarm stop? These and many other similar questions are the concerns of various car owners. It seems like a great idea to install an alarm system to help protect your vehicle.

Still, it would be inappropriate if your car alarm keeps going off in an apartment complex without any threat. It becomes more annoying when you can’t find the actual cause of the alarm going off. 

In some cases, it could result from a bad weather condition, as there are often reported cases where the wind causes the car’s alarm to go off. But, if after adjusting the shock sensor to suggest it acts less sensitive and the problem persists, it could be due to another issue. 

Thus, you need to do something to turn off the car’s alarm and restore the peace of the environment as soon as possible. Here are some things you can do to quickly put the alarm off.

Try to Unlock the Door

It is always the case of a locked vehicle to give off the alarm sound if tampered with but you can stop the alarm by unlocking the vehicle. Will the car alarm go off if the car is unlocked? Well, most cars come programmed in a manner that allows the alarm to shut off once the driver inserts the car keys or uses the key fob button.

In most cases, this seems like the easiest thing to do when the car alarm goes off. You can quickly unlock the driver’s door to stop the alarm. Supposing the car appears unlocked at that moment, you can get it locked and reopened again.

Start the Vehicle

Remember, the alarm must prevent the car from theft. So, if you unlock the vehicle and turn on the ignition, the alarm system can tell that everything is fine. Thus, the sound should go off automatically. 

Nevertheless, some cars do not start when the anti-theft alarm is still active. But, if your car allows such, try to turn the key in the accessory position to signal the alarm computer to stop the commotion.

Start Disconnecting the Fuse

If your Lexus car alarm keeps going off, you may need to get the alarm control fuse disconnected in extreme cases. You should find the location of this fuse; you can check the car’s manual to find the exact location of the fuse. 

Nevertheless, you can often find it within the engine’s compartment, and remove it once found. You can replace the fuse to see if the problem continues. When you notice that the alarm works fine with the replacement fuse, then the old fuse must have been faulty.

Get the Battery Disconnected

If after trying all these solutions hinted above your car alarm keeps resounding without threats, you may need to get the vehicle’s battery disconnected. By now, you should know that the alarm system can only work with a power supply.

Thus, removing the battery would shut the alarm down until your car expert comes to look at the problem. So, wear your gloves and open the car’s hood. Then, get the negative terminal disconnected and place it at a point where there is no contact with the battery.

Read Also: Best Key Programming Machine for All Cars

How do you Fix a Car Alarm That Keeps Going Off? 

It seems pretty sensible to know the reason behind your Honda Civic or Honda CRV alarm going off continually before seeking ways to fix the problem. You can look through the common reasons why most car alarm keeps going off, explained above.

The common cases explained above can provide clues to help you find the cause of your car alarm going off. With that in mind, below are the best ways you can fix such a problem based on the symptoms you notice.

Rusty Battery

If your car’s battery has terminals that appear corroded despite having a good charge, it would help to get them cleaned. Such a rusty battery terminal can always cause the vehicle’s alarm to go off without potential threats.

There are many chemical battery cleaners available in the market, and you can easily get one for this purpose. Such battery cleaners are available at different prices, and you can get one for as low as $5.

Kindly ensure that the battery gets disconnected first before applying the cleaner. Then, follow the manufacturer’s recommendation as you spray the cleaner and get rid of the corrosion. Once done, the good condition of the electrical connection should make the alarm system work in good condition.

Battery Replacement

One thing that could cause a malfunctioning car alarm is a low battery, and as such, it would help if you check the battery’s voltage. Using the voltmeter, check the kind of charge your battery currently has to know if it is the cause of the problem.

If you find anything lesser than 12.6 volts, it means that the battery is dead and would be needing a suitable replacement. There are various battery options in the market, with a price range of $150 and above. You should get a suitable car battery to replace the dead one.

Fixing the Shock

A simple test on the shock sensors would tell if they are the reason why the vehicle’s alarm keeps going off. If during the test you notice that small vibrations against the car would set the alarm off, it would help if you adjust the sensors.

You can do that manually by adjusting it down and making it less sensitive. Kindly find the shock sensor’s control box beneath the dashboard (on the driver’s side). Then work on it as desired and test afterward.

Reinstalling the Alarm

If your car has an aftermarket alarm fixed, it could be that it was poorly installed if the alarm keeps going off. In such a case, it would help if you take the car back to the car expert who had installed the alarm in the first place.

Working on the Hood Latch Sensor

In most cases, a dirty hood latch sensor could make the alarm keep going off. Thus, it would help if you gently get it cleaned. You can employ a soft brush and brake cleaner and gently work on it. You should be able to find the location of the hood latch sensor from your car’s manual. 

But, if the hood latch sensor appears clean and the problem persists, you should try to get it disconnected and reconnected again. Perhaps it seems loose and installing it tighter would help fix the problem.

Fixing the Faulty Key Fob

If the key fob is the cause of the alarm going off constantly, you should check it and replace the batteries. You can find compatible batteries from the grocery shop near you at an affordable cost. There are good key fob batteries that cost below $5 and would work for some years.

Upgrade Your Car Security 

Having some car security upgrades can keep your mind at peace, as it ensures that your vehicle remains safe to an extent. Thus, it is pretty recommendable that you invest in some of the best security upgrades you find available.

If you are thinking of upgrading the security of your car, here are some excellent options that you should consider.

Installing Car Alarms

The car alarm system works excellently in keeping the vehicle safe from thefts and even potential damages. The device works with various sensors that come attached to a siren (loudspeaker), causing an audible sound when there is a threat.

Some of the sensors you would find include pressure sensors, motion detectors, and switches. Why should you get the alarm system installed in your car? Well, taking such a step would protect the vehicle from theft, as it signals that someone is trying to break in.

Again, this option is cost-effective and seems like a simple option rather than hiring some security operatives to watch over the car at all times. Furthermore, the car alarm system would help lower the insurance premium of your car.

Back-up Battery Kit

It is well-known that the car alarm can work when there is a power supply, and thieves may remove the car battery to ensure that the siren does not go off. However, the backup battery kit would be there to supply enough power for the alarm system to keep working.

Thus, this kit seems like a necessary security upgrade that you should get for your vehicle. With such an upgrade in place, you can rest assured that your car would be safe and protected from potential harm.

Location Tracker

the GPS tracker would go a long way in keeping your vehicle secured, much more if you travel on the highway most of the time. When installed, the GPS tracker would remain undetectable, and as such the thief would not have a clue that you are tracking him.

Since the system is certified and licensed, you can use it without worries. Hence, your car can stay safe even with the current cases of theft and carjacking. Once you know the location of your vehicle, you can easily retrieve it.

Keyless Entry

This type of car key is another security upgrade that you should consider, as it seems harder for thieves to break in once installed. Again, using the keyless entry seems pretty convenient and you can lock the quickly without shuffling through a bunch of keys.

Car Alarm Keeps Going Off – How To Fix It YouTube Video

Final Words

The car alarm system is pretty crucial for ensuring the safety of your vehicle, as it prevents potential thefts and damages. Nevertheless, it seems quite annoying when the car alarm keeps going off without such threats. Such a thing occurs due to various reasons, and it would help if you learn about them.

 My car alarm keeps going off when I open the door, what could be the cause? Well, it could be due to a faulty door latch alarm. There are other common causes explained in this piece, and you can learn the tips and tricks of fixing such problems when it occurs.


Hi There, I am R. Hasan Tito, a mechanic, and owner of this website. My friend and I created this website to share our knowledge, expertise, and experience with our fellow mechanics' community and car users. I am a specialist and certified automotive mechanic (Both Heavy Commercial and Private Cars). I have been working as a mechanic for over fifteen years. I worked for a long time at Global Rebound Automotive companies (Toyota, TATA, BMW, Nissan, TVs, and Others ) as a Mechanic and Mechanics Supervisor.

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