# Electronic car protection: alarm, immobiliser, GPS and OBD _Updated: 8 November 2026_ **Short answer:** Electronic car protection means devices that keep a thief from driving the car away: an immobiliser, an alarm, GPS and OBD protection. Each one stops a different way of stealing, so they are chosen together, to suit your car. > **The service we recommend: Immobiliser** The engine will not start without your fob or code, even with the key. We tell you the price when you tell us the model. [More about the service](https://autoindustrija.rs/en/services/immobiliser) ## How a thief fools the factory protection Almost every car made after 1998 has a factory immobiliser. There is a small chip in the key, and the engine starts only when the car recognises that chip. The factory immobiliser only checks whether the key is known. So the thief tricks the car into believing the key is genuine. Each way of stealing is stopped by a different protection: - **A new key through the OBD port:** The OBD port is the spot under the steering wheel where diagnostics is plugged in. The thief gets into the car, plugs his own device into the port and makes a new key in a few minutes. [OBD protection](https://autoindustrija.rs/en/obd-protection) prevents this. When the car also has the immobiliser we fit, the engine does not start even with the new key. - **Keyless theft:** A keyless key unlocks and starts the car from your pocket. Thieves pick up the signal of your key and relay it to the car, then unlock and start the car as you would. An immobiliser that asks for your fob and a pouch that does not let the key signal out stop it. [More about keyless theft](https://autoindustrija.rs/en/advice/keyless-car-theft) - **The headlight attack:** The thief removes part of the bumper, connects to the wiring by the headlight and sends the car a fake message that the key is valid. An immobiliser or an alarm that blocks starting stops it. [More about the headlight attack](https://autoindustrija.rs/en/advice/headlight-can-injection-theft) - **Break-ins and theft of belongings:** The thief breaks a window and takes things from the car. The siren and the message on your phone come from an [alarm](https://autoindustrija.rs/en/services/car-alarm-installation). - **The car taken away on a tow truck:** The thief does not start the engine but lifts the car and takes it away. An immobiliser does not show where the car is. [GPS tracking](https://autoindustrija.rs/en/services/gps-vehicle-tracking) does. ## An immobiliser stops the engine from starting without you The immobiliser we fit works alongside the factory one. The engine starts only when the car has both the right key and your confirmation. A thief does not get that confirmation with a new key, with your key signal, or with a fake message through the wiring by the headlight. The confirmation can be: - **A fob:** You carry it in your pocket. When you get into the car, the immobiliser recognises it by itself and the engine starts as before. - **A code:** A sequence of presses on buttons the car already has, on the steering wheel or the door. You choose the sequence. - **A phone:** With some units the phone works like a fob. You carry the phone with you, and the immobiliser recognises it by itself when you switch on the ignition. The unit is small and we hide it among the car's cables, so a thief does not see it and has a hard time finding it. Do not keep the fob on the car key and do not leave it in the car. If a thief takes the key together with the fob, he has everything. [More about the immobiliser](https://autoindustrija.rs/en/services/immobiliser) ## An alarm warns you and the people around the car An alarm sounds the siren when someone opens a door, hits or moves the car. A light knock gives a short warning, and a hard one sets off the siren. An alarm that notifies your phone has its own SIM card. When the alarm goes off, you get a message or a call. An alarm with GPS also shows where the car is. The factory alarm is switched off with the key. A thief who makes a new key or relays your key signal unlocks the car like the owner, so the alarm does not go off. On a newer car we connect the alarm to the car electronics, so it switches on when you lock the car with your own key. When the alarm has an engine block, we set it so it does not switch off without your fob. Then a thief cannot start the engine with your key, or with a new key made through the OBD port. We connect the engine block so it prevents starting and does not stop the engine while you drive. The Serbian rulebook on vehicle technical requirements says an anti-theft device must not be able to switch on while the car is moving. [More about alarm installation](https://autoindustrija.rs/en/services/car-alarm-installation) ## GPS shows where the car is GPS does not stop the thief, it shows where the car is. According to Ministry of the Interior data, only about half of the vehicles stolen in Belgrade in 2022 were found. With GPS you show the police where the car is, instead of waiting. The unit sends the location over a SIM card, and you see it in an app on your phone. You see where the car is now and where it has been. A message arrives as soon as someone starts, lifts or tows the parked car. A unit with its own battery keeps working even when the thief removes the car battery. In an underground car park or a tunnel there is no satellite signal, so you see the last location before entering. A thief can cut the signal with a jammer, a device that drowns it out, and better units recognise the jamming and notify you. We hide the GPS unit under the trim, with no visible wires, and fit it together with an immobiliser, an alarm or OBD protection. [More about GPS tracking](https://autoindustrija.rs/en/services/gps-vehicle-tracking) ## OBD protection stops a thief from making a new key Through the OBD port a mechanic reads fault codes and makes new keys. A thief can buy the same device. On every car of the same model the port is in the same place, usually under the steering wheel. We protect the OBD port in 2 ways: - **OBD port relocation:** We fit a hidden socket, and you get a small adapter. The factory port stays where it is, but does not work without the adapter. At the service and the roadworthiness test you plug the adapter into the hidden socket, and the garage connects to the factory port as before. [More about OBD port relocation](https://autoindustrija.rs/en/obd-port-relocation) - **Electronic OBD blocker:** The blocker switches the port off, so a thief cannot make a new key through it. For a service or the roadworthiness test you switch it off with a fob, code or adapter. [More about the OBD blocker](https://autoindustrija.rs/en/services/electronic-obd-blocker) OBD protection does not protect against keyless theft or the headlight attack, because they do not go through the OBD port. That is why we fit an immobiliser with it. [More about car theft through the OBD port](https://autoindustrija.rs/en/advice/obd-car-theft) ## Which protection to choose for your car We choose protection by how your car gets stolen. Each next protection should stop a way of stealing that the previous one does not stop. - **A car with an ordinary key:** OBD port relocation and an immobiliser. A thief cannot make a new key through the port, and without your confirmation the engine does not start even with a key. - **A car with a keyless key:** An immobiliser and a key pouch, and against theft through the OBD port, relocation or a blocker. - **Toyota or Lexus:** An immobiliser or an alarm that blocks starting. Thieves also steal these makes through the wiring by the headlight, where OBD protection does not help. - **An expensive car:** OBD port relocation and a blocker, and an immobiliser and GPS as well. - **The car stays outside at night:** Alongside the protection you chose, an alarm that notifies your phone. Visible mechanical protection, such as a steering wheel lock, shows a thief that more work is waiting for him. [More about mechanical protection](https://autoindustrija.rs/en/advice/mechanical-car-protection) [More about the best theft protection](https://autoindustrija.rs/en/advice/best-car-theft-protection) ## What the price of electronic protection depends on There is no single price, because every car needs a different unit and different work. The price includes the unit and the fitting. **The price of electronic protection depends on** - Which protection you choose. - What the unit does. An immobiliser asks for a fob, a code or a phone. An alarm can have a siren, an engine block, a message on your phone or GPS. - The make, model and year of the car, because they decide how the unit is connected and where it is hidden. - Whether the unit works over a SIM card. GPS also has a monthly tracking fee, and an alarm that notifies your phone may have a cost with the mobile operator. [More about the cost of car protection](https://autoindustrija.rs/en/advice/car-theft-protection-cost) Some insurers give a discount on comprehensive cover if the car has an extra anti-theft device. Ask your insurer whether your protection counts for the discount. [More about comprehensive cover and theft](https://autoindustrija.rs/en/advice/comprehensive-insurance-car-theft) ## Frequently asked questions ### Does electronic protection drain the battery? A little. A healthy battery copes with that for weeks. A weak battery feels it if the car stands for a long time. ### Can electronic protection go on an older car? Yes. For an older car there are immobilisers that connect differently than on a newer one, and the alarm gets its own remote. ### Does the protection get in the way at the roadworthiness test? No. The OBD port is also checked at the roadworthiness test, so after relocation you bring the adapter, and you switch the OBD blocker off. When you hand the car over to someone else, put the immobiliser and the alarm in service mode. Have a question about your car? Message us on WhatsApp or call 067 774 1606. ## Read also - [Car theft in Serbia: 9 ways thieves steal a car](https://autoindustrija.rs/en/advice/how-cars-are-stolen-in-serbia) - [OBD car theft: how thieves make a new key](https://autoindustrija.rs/en/advice/obd-car-theft) - [Keyless theft (relay attack): how it works, how to stop it](https://autoindustrija.rs/en/advice/keyless-car-theft) --- Page on the website: https://autoindustrija.rs/en/advice/electronic-car-protection auto-industrija, Belgrade. Phone and WhatsApp: +381677741606. E-mail: kontakt@autoindustrija.rs.