False car alarms

Modern car alarms are a complex and multifaceted set of components. Therefore, there can be many reasons for self-triggering.

Including a siren can wake up the entire yard due to excessive sensitivity of sensors or errors with the installation. A logical question arises, why does the alarm go off just like that? If a problem occurs regularly, it is necessary to check the correct configuration of the system itself. The next step is the diagnostics of electrical circuits.

Why the alarm goes off by itself-who is to blame and what to do

Failures in the correct operation of sensors;
vehicle overload;
moisture gets into the outside of the system;
oxidation of the contacts, causing the alarm system switches to close.

Errors with sensor sensitivity adjustment

The basis for triggering is the detection of vibration and the direction of the signal to the siren. For correct operation of the anti-theft system, be sure to take care of the correct settings of the sensors.

The following order of work is supposed:

Determine the location of the sensors. Security systems of older generations assumed the location of sensors near the head unit, to which the connection was made by means of cables. The housings were made with bolts, and it was with them that the degree of sensitivity was regulated. Modern complexes are made with sensors already integrated into the head unit.

Work on corrections. In the case of old systems, the bolts on the bodies are tightened with a screwdriver with a figured nozzle. But you need to have experience and skills in such adjustment of parameters. Without proper experience, it is possible to configure sensors in such a way that they will trigger too often for no reason. You should refuse to set the sensitivity too high-the slightest vibration will be enough to trigger the installed sensors.

If we talk about modern anti-theft devices, then the sensors in two-way alarms on a car are configured with a key fob. It is recommended to set average sensitivity values so as not to worry about false alarms of the system.

Checking for problems with contacts

The consequence of damage to electrical circuits, the integrity of the insulation can be a periodic unauthorized activation of the alarm.

The most common reason why the alarm goes off on its own is errors with the connection of the anti-theft system.

At the same time, the risk of damage to electrical circuits during operation increases for devices that support blocking of the engine, ignition switch or fuel tank.

To fix a malfunction in this case, the help of a competent car service is simply required.

Low battery

In the event of a minimum battery charge, the alarm will be constantly activated. In the operation of two-channel security systems with an LCD display, a light or sound notification about a lack of energy is displayed.

Two methods can be used to fix the problem:

Determine the voltage with a voltmeter with the engine off. When a value less than 11.8 battery appears on the screen, you should definitely think about recharging. The normal indicator will be in the range of 12.5-13V.
It is necessary to exclude damage in electrical circuits. The consequence of the problem is often a rapid discharge of the battery. The system is checked with a multimeter, with a transfer to the ammeter mode. The positive contact is connected to the battery, the negative contact to the ground terminal. The break points are ringed with a multimeter when the electrical appliances are disconnected. In the event of a leak, it is assumed that the elements of the system are connected in turn. Thanks to the normalization of the current strength, it is possible to identify the damaged part of the circuit.

Incorrect operation of the sensors can lead to false alarms for movements near the car. To remedy the situation, you can remove a separate element of the system, with a change in location.

An alarm may also be triggered in case of vehicle overload. The reason for the sensor activation can be a change in the total amount of air-sometimes it can be perceived as an attempt to steal a car.

Excessive moisture problem

The result of moisture entering the wiring is the unreasonable triggering of the alarm mode.

Humidity can increase due to various circumstances:

Heavy rainfall;
Condensation occurs as a result of sudden temperature fluctuations (the siren is usually triggered at night);
Ingress of moisture into sensors and head unit during car wash;
Clogged rainwater gutters.

Fixing the problem

Engine shutdown;
Disconnecting the battery terminals;
Disconnect the cables that power the car alarm head unit;
Remove the housings of the sensors and the control unit from the on-board network, but only after de-energizing;
The electronic board should be blotted with a soft cloth or brush;
All parts of the system are thoroughly dried using a hair dryer with warm air;
Installing part housings, connecting appropriate cables;
The alarm is switched to work in security mode.

Oxidized limit switches

Often the cause of the problem, why the alarm is triggered just like that, are errors in the installation of the alarm. In this case, it is assumed that the limit switches are located on the hood, trunk or door.

It is necessary to take into account the rather rapid failure of such parts, with triggering even without trying to open the lock. The malfunction can be eliminated thanks to a set of the following measures:

Restoring the correct position of the parts of the locks-with the adjustment of the hinges with a hex key;

Oxidized areas are cleaned with sandpaper;

Replace limit switches if damaged.

EMI Problem

In megacities, an increased intensity of the electromagnetic field is characteristic, which provokes interruptions of security systems.

Spontaneous activation is caused by exceeding these values specified in the alarm data sheet.

There is a typical problem of triggering near the towers of mobile operators, trolleybus, tram tracks, power lines, industrial zones. In this case, it is better to think about changing the standard parking spot.

In each case, the situation must be considered individually in order to clearly understand why the alarm is triggered in the car. If you regularly experience problems with the car immobilizer and alarm, it is better to contact a qualified service center.

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