A car alarm is a reliable protection of personal property from robbers and hooligans. Thanks to modern encryption methods, specialized reading devices cannot help attackers commit bad deeds. Each force impact on the car leads to the inclusion of a light and sound signal and automatic sending of a message to the driver of the vehicle.
During operation, security systems fail, so many owners often face the problem of not being able to open their cars using the key fob. What reasons there may be for this and how to deal with them will be discussed below.
Reasons why the car does not open with the alarm key fob
If the car does not open using the key fob, the problem may be due to one of the following reasons:
- the car battery is discharged;
- possible factory defect of the alarm system;
- wire separation;
- errors were made during installation;
- defective central locking;
- and many other reasons that need to be understood.
The problem is in the key fob itself
If the car does not respond to the alarm key fob, then first of all you need to check the serviceability of the key fob itself. Initially, it is necessary to assess its external condition for mechanical damage. There should be no deformations or cracks. If the display itself is turned off or shows errors r99, zzz, check, then the reason why the alarm does not respond to the key fob lies in the system itself. Diagnostics can only be done in a workshop.
If your car alarm doesn't go off while the engine is running, then it's all about the batteries. If this solution does not help, then it is necessary to perform a complete reprogramming. For example, you can restart the program yourself. Until the breakdown is fixed, you will have to use only one key. Software errors and manufacturing defects can only be eliminated by professionals.
Not always, if the problem is that the remote control is broken, you can replace the key fob or solve this problem in the service center, most often you come to change the alarm completely.
Low battery
The car won't start, the alarm won't go off - this is a problem with a dead battery. To charge it, you need to reset all settings in accordance with the prescribed instructions and perform reprogramming. In 50% of cases this is exactly the case. As soon as the battery is charged, try setting the car alarm; if this fails, the activation icon will appear on the display, which means you need to reprogram.
Central locking defect
The reason why the alarm key fob may not work and not respond to actions may lie in the central unit. If this is the reason, then characteristic freezing of the signal button itself will be noticeable. The car alarm relay is not connected to the signal unit, which is the responsibility of the central unit.
Worn or frayed wires may disable the locking of one of the doors. It will be necessary to replace the wire in any case, but repairs can be made for various reasons.
Incorrect installation of the system
If the Starline alarm starts, but the doors cannot open, this may indicate failure to comply with the installation details and incorrect settings. This is often associated with the following phenomena:
- The user did not study the manual for installation and further operation of the Starline alarm system and decided to install a transceiver with an antenna and transmitter near the electronic elements or metal parts of the machine. In this case, strong interference occurs, which degrades the signal quality.
- The driver installed the adapter with the antenna on the glass with a protective film. Its presence creates a shielding effect, due to which the signal ceases to be supplied normally to the key fob and the central alarm unit.
Modern service centers provide installation services for alarm systems in a matter of minutes. They also eliminate mistakes made during self-installation. Most operations involve dismantling the instrument panel and then installing working elements.
Reasons for spontaneous alarm activation
The main reasons why car alarms can go off in the absence of external danger are:
- problem with the shock or tilt sensors;
- presence of moisture in external systems;
- electromagnetic interference is possible in the car parking area;
- deliberate actions on the part of car thieves;
- power supply leak;
- vehicle overload;
- oxidation of contacts.
Let's consider each situation separately.
Leakage in power supply
If your battery is discharged to a critical state, the alarm can start working normally. Typically, all key fobs provide a mode for indicating the voltage in the on-board network. If the readings are below 11.5 W, a sound signal will be transmitted to the key fob. In your case, you will need to double-check the voltage in the battery and the presence of possible leaks in the power circuit.
Increased level of electromagnetic waves in the parking area
Each manufacturer indicates in the instructions the technical characteristics of the level of noise immunity. In both urban and rural areas, there are places where the electromagnetic field level is elevated, which can cause the vehicle alarm to malfunction. Most often, such areas are located near:
- trolleybus overpasses;
- power lines;
- industrial zones.
The only solution to this problem is to find another place to park the car.
Alarm wiring fault
Often, car alarms are installed by non-professionals, who can disrupt electrical installation technology. It may start to fail even after 5-7 years if there have been faults in contacts or connections. Each case is individual, but in most cases it is easier to dismantle the old alarm system and install a new one.
Moisture ingress
Car owners of older car models often face this problem. The standard place to install an alarm in “older” vehicles is the dashboard near the left knee, where moisture can easily enter, especially during the autumn rainy season. At this time, it is imperative to clean the drains.
If water gets into this area, you need to follow a step-by-step action plan:
- Turn off the ignition.
- Remove battery seals.
- Disconnect the alarm connector from the head unit.
- Carefully disassemble the housing.
- Clean the circuit board using a cotton swab and alcohol.
- Dry it with a hairdryer, but not more than 130 degrees.
- Reassemble the structure.
Sensor malfunction
Incorrect operation and increased sensitivity of sensors can lead to false alarms during bad weather conditions. In modern cars, two-level sensors are usually installed that respond to weak and strong impacts. Sensitively installed during installation. If it is elevated, then this most often leads to a false alarm.
Central locking device
In a simplified form, the central locking system consists of the following main elements:
- control module;
- controllers or microswitches;
- actuators or actuators.
The central lock can work both contact and contactless. In the first case, a key is used to open and lock it, in the second - a key fob.
When the system is locked with a key, the following processes occur:
- by turning the closing element in the well, the microswitches are activated;
- from them the signal is sent to the door control unit, and from there to the central control module;
- the module receives and processes the signal, activating actuators;
- the locking elements are fixed.
If actions are carried out without a key, the signal, when the button is pressed, is sent to the antenna in the central control module, where it is processed and sent to peripheral systems, the actuators block the locking mechanisms.
In this way, you can control not only the door mechanisms, but also elements of the trunk, hood, and gas tank flap.
A distinctive feature of the system’s functioning is that it is not related to the operation of the car itself. That is, it works regardless of the ignition state and when it is opened, engine operation is not blocked.
IMPORTANT! Unlike an alarm system, the central locking serves more for the convenience of the user than for the safety of the machine.
Problems with the signal sensor
If you have changed the batteries and are sure that the problem is not with them, the problem may be with the signal sensor. It occurs due to frequent pressing of the remote control buttons. To open the car in this case, you need to use a spare key and send the faulty one for repair.
Photo instructions on how to increase the range of a standard key fob
Drained car battery
The next most popular reason is a dead battery. There are two ways to open a car with a similar problem:
- The main way in such a situation is to recharge the battery from a third-party battery. Connect the negative and positive terminals to the metal part of the car and the starter, respectively.
- Even with a discharged battery, the car can be opened. To do this, you should bring the key fob as close to the car as possible and, by repeatedly pressing the lock unlock button, gain access to the locked vehicle. However, after this you will still need to charge the battery.
To avoid getting into similar situations in the future and to avoid draining the battery, do not leave the car with the heater, radio or headlights on.
Do not forget that changing the battery may also cause a software failure. Immediately after the battery is returned, the car security system may function intermittently. It is usually worth waiting a little for the system to get rid of errors in its operation.
Video about repairing the Starline remote control
The Blue Box Ufa channel in its video showed in detail the procedure for restoring the functionality of the communicator from the Starline alarm system.
Do you have any questions? Specialists and readers of the AUTODVIG website will help you ask a question
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Faulty car electronics
Other reasons for the inability to open the car with the key fob include problems with the vehicle electronics. This may be due to a breakdown of the electronic control unit and power surges.
Often this can happen if radios are installed incorrectly, including Chinese models. Independent attempts to install new models of such radios in old cars can lead to complete dysfunction of the vehicle wiring.
If you notice involuntary openings and closings of your vehicle that are beyond your control, urgently take your vehicle to the nearest service station.
Photo gallery
The photo shows the correct connection of the car alarm
OS-7 on the display - one of the signaling errors
Example of damage to a key fob
Operating principle of central locking
Types of central locking elements
The control button in the cabin can be one on the driver's door or on the panel, or two on both front doors. When installing an alarm system, it is advisable to avoid interfering with the central locking control units. We are talking about contacts located in the middle. The current consumption of a conventional electric central locking drive can reach 5A at its peak. Recommendations: For self-installation, simple security systems with a minimum set of sensors are more suitable.
More articles from the Tuning section. The schematic diagram is taken from the Opel Astra F repair and operation manual. To connect to the central locking, you need to know what type of central locking is installed on your car. Drives equipped with switches, each with three contacts, are mounted on the car doors and in the luggage compartment lid. Alarm installation
