The alarm does not respond to the key fob
Content
Modern machine security systems reliably protect against theft, but they themselves can become a source of problems. The most common of these is signaling. does not respond to keychain, not allowing you to disarm the car or turn it on.
Accustomed to doing without a key, the owner of a car sometimes cannot even get into the salon without outside help. Most often, the key fob itself is the culprit of such troubles, but failure of the main unit of the security system or external causes is not excluded.
You can find out how to find the cause of the problem and what to do when the car does not respond to the alarm key fob and does not allow you to unlock the doors, you can learn from our article.
Why is the car not responding to the alarm key fob
The reason for the lack of response of the alarm to pressing the buttons on the key fob can be either the failure of the components of the security system itself - the key fob, transmitter, main unit, or external barriers that prevent signal transmission and reception. To understand why it is not possible to disarm the car or turn on the alarm with the key fob, you can use the combination of characteristic features. The table below will help you with this.
| Evidence | Most likely causes |
|---|---|
|
|
|
|
|
|
In addition to the actual malfunctions and interference, the reason that the alarm does not respond to the key fob may be an unsuitable case. Most often, this problem appears when using non-standard silicone products without slots for buttons. The owner may have the feeling that the key fob responds to pressing the buttons every other time. In reality, they simply do not sink to the end and do not close the contact.
The main breakdowns of the car alarm key fob
5 possible reasons for the breakage of the key fob: video
If the alarm does not respond to the key fob due to external interference, only changing the parking place or replacing the security system with a more noise-resistant one, controlled by GSM or via a mobile application, will help. In order to restore a failed car alarm base unit, SMD installation skills and a soldering station are usually required. But in some cases it is quite possible to repair the alarm key fob on your own without special knowledge and tools. The same applies to minor software failures in the operation of the security system and disruption of its connection with the antenna unit. A description of the basic reasons for the lack of response of the alarm key fob to pressing buttons and ways to solve the problem is presented below.
Shutdown or blocking. Most alarm key fobs can be disabled or blocked by pressing a certain combination of buttons. Before looking for a breakdown, check if the key fob has turned off and if the protection against accidental pressing of buttons has been activated.
Usually in this case, when you press the buttons, an inscription like “Block” and “Lock” appears on the screen, a symbol in the form of a lock, vehicle parameters are displayed or all symbols are lit, but nothing may happen. Combinations for unlocking and enabling / disabling the key fob for your security system model can be found on the manufacturer's website or by calling the hotline, or try one of the following.
| Security system brand | Power on/unlock combination |
|---|---|
| Pandora, Pandect D, X, DXL series | Press and hold button 3 (F) for 3 seconds |
| Starline A63, A93, A96 | Simultaneously press buttons 2 (left arrow) and 4 (dot) |
| Starline A91 | Simultaneously press buttons 2 (open lock) and 3 (asterisk) |
| Tomahawk TW 9010 and TZ 9010 | Simultaneously press the buttons with the symbols “open lock” and “key” |
| Alligator TD-350 | Sequential pressing of the buttons “open trunk” and “F” |
| SCHER-KHAN Magicar 7/9 | Simultaneously press the buttons with symbols III and IV |
| CENTURION XP | Briefly press the button with the “open trunk” symbol, then press and hold the “locked lock” for 2 seconds |
Oxidation of contacts after exposure to moisture, click to enlarge
Lack of power. If the alarm key fob has stopped responding to the buttons, then the most common reason is a dead battery. In a situation where it is impossible to replace the battery, but you urgently need to open the doors and disarm the car, you can try to remove the battery and squeeze it slightly in the center or simply knock it on a hard object, such as a wheel disk. This will lead to the activation of chemical processes and the appearance of a charge that will be enough for one operation.
Closing and oxidation of contacts. Often the alarm stops responding to the key fob after it gets caught in the rain or falls into a puddle. The reason for the oxidation of the contacts may be the electrolyte flowing from the worn out battery. If the key fob gets wet, you should remove the battery as soon as possible, disassemble the case, dry the boards thoroughly. The resulting oxides are removed with a soft toothbrush and a cotton swab or alcohol wipe soaked in alcohol.
Mechanical damage to buttons, cables and components. If the keyfob case is strongly shaken, contact between its boards may be lost as a result of loosening and removal of contacts or disconnection of cables. If the alarm key fob stopped working after a fall, you need to open the case, check the integrity of the boards, cables, contact pads.
If there is no visible damage, try disconnecting and reconnecting the connectors. In cases where the alarm key fob does not respond to pressing individual buttons, special attention should be paid to them. You can check the performance by connecting the probes of the tester in the dialing mode to the terminals of the microswitch and pressing the button.
Replacing worn buttons, click to enlarge
If there is no signal, it will have to be replaced. In this case, you will need a soldering iron, and the microswitch itself can be selected by size in a radio parts store.
Software failure (key fob decoupling). When installing an alarm, the procedure for prescribing key fobs in the main unit of the security system is carried out. In the event of a software failure, errors in setting up an alarm, a power outage, as well as an attempt to hack, initialization may be reset. In this case, all previously linked key fobs will be unlinked from the alarm.
In this case, the procedure must be carried out again using the Valet button, special software, connecting a PC or laptop with a cable to the connector in the main alarm unit or via a wireless channel (some modern models of security systems have this option).
The procedure for prescribing key fobs can be found in the instruction manual. Occasionally, the failure can be eliminated by rebooting the main unit, which can be done by removing the terminals from the battery for 20–30 seconds. If the alarm module is equipped with its own battery that provides autonomous power, this method will not help!
Broken alarm key fob antenna
antenna failure. The security system transceiver can be located inside the main alarm unit or in a separate housing. The latter is usually mounted on the windshield. In case of mechanical damage to the remote antenna, the communication range with the key fob will drop dramatically and it will only work in close proximity to the car or inside it. If the wire connecting the transmitter to the central unit is accidentally frayed or cut off, the base and additional key fobs will completely lose contact with the machine.
The reason for the malfunction of the remote control may be damage to its own antenna when it falls. Typically, the antenna is made in the form of a spring and soldered to the transceiver board. If the connection deteriorated after the keyfob fell or hit, while the additional one works correctly, you should disassemble the base console and check the condition of the antenna connection to the board and the contact of the transceiver with the second keyfob board.
What to do if the alarm key fob does not respond to button presses
When it is not possible to open or close the car with an alarm key fob near the house, first of all, you should try to repeat the steps using a spare key fob and tag. Successful disarming of the car with their help indicates a breakdown of a particular remote control.
What to do if the alarm does not respond to the key fob: video
If the alarm does not respond to additional key fobs, or they are not available, and the quick fixes for basic problems described above do not help, several options are possible.
There are 3 ways to turn off the alarm on the car:
- deactivation by a command from the phone (only available for models with a GSM module);
- secret button Valet;
- physical shutdown of the alarm unit.
Arming and disarming via GSM/GPRS module
Control of the alarm and additional options through a mobile application
Suitable only for modern security systems equipped with a GSM / GPRS module. To disarm, you need to launch the application on your smartphone or send a USSD command (for example, *0 for Pandora or 10 for StarLine), having previously dialed the number of the SIM card installed in the module. If the call is made from a phone that is not registered in the system as the main one, you will additionally need to enter a service code (usually 1111 or 1234 by default).
Similar actions can be performed using a mobile application from a linked device or from the security system website by logging into your personal account - the login and password from the service card included in the alarm kit are used to enter.
Emergency shutdown of the alarm with the Valet button
The presence of the "Jack" button in the alarm circuit helps to manage the alarm in an emergency
To disarm the car, you need to get into the salon by opening the door with a key or in an alternative way. You can turn off the siren that has worked at the same time by having a snack and disconnecting one of the wires going to it under the hood, after disconnecting the battery. If there are no alarms when the door is physically opened, you should check the battery charge - perhaps the problem is in it.
The alarm is deactivated by sequentially pressing the Valet service button in a certain sequence with the ignition on. The location of the Jack button and the combination will be individual for a specific alarm model (always available in the manual for it).
Physical disconnection of the main alarm unit from the vehicle wiring
The cause of the breakdown may be a blown fuse, usually located near the alarm unit
It is better to entrust the performance of this operation to specialists of installation centers of security systems.
An independent search and dismantling of all modules blocking the operation of the internal combustion engine and ignition will take several hours, and performing repairs in the absence of skills and tools is associated with the risk of damage to interior elements, standard wiring and electronics.
Only the simplest signaling units without feedback and an immobilizer are relatively easy to dismantle if there is a connection diagram.
