Car Immobilizer: Basic Function and Bad Symptoms


A car immobilizer does just what the name indicates. It is a technological security device that will prevent your car from moving. In other words, it is an anti-theft device that will prevent thieves from being able to hotwire your car and drive it away.

Basic Principle

The only one who will be able to start your vehicle is whoever has the key. There is a digital token which gets sent from the key to the immobilizer whenever you attempt to start your vehicle. If the wrong token is sent or no token at all is used, then your starter motor, ignition, and fuel system will remain disabled by the immobilizer. This is great news for responsible car owners who want to prevent their cars from being stolen. However, if you lose your car key, then you need to go to the dealership and pay hundreds of dollars for a new one.

The Top 5 Bad Symptoms

For the security of your vehicle to be sustained, the car immobilizer system and the transponder chip in the key both need to function properly. If either one of them wears out or gets damaged, then it could cause a whole array of problems and symptoms. Below are the top 5 symptoms that you can expect to experience with a bad car immobilizer.

Door Won’t Unlock – If you press the unlock button on your car key and the car door does not unlock, this is a sign that your key fob is not registering with the immobilizer system. Perhaps the battery in your key needs to be replaced or the immobilizer system itself is having issues. Whatever the case may be, your key fob will not be able to be transmitted properly without a functional key and immobilizer. In the meantime, you will either need to call a locksmith or have your car towed to the dealership so that you can unlock your door again.

Door Won’t Lock – If you cannot unlock your door, then you probably won’t be able to lock your door with the key either. This means that you’ll need to either leave your doors unlocked or leave the windows down if the doors automatically lock after a certain period of time. Until you get the problem fixed, your vehicle will be vulnerable to thieves, vandals, and bad weather if you leave your windows down.

Alarm Won’t Function – The alarm system in your vehicle is associated with the same security feature as your immobilizer. If you have a bad immobilizer, then you’ll likely have a bad alarm system too. Depending on the type of alarm system that you have installed, this means anyone breaking your windows or stepping near your vehicle will no longer cause the alarm sound to go off.

Engine Won’t Start – The immobilizer will normally prevent the engine from starting if the proper security token is not given to it. Sometimes you may be able to lock and unlock your vehicle, but the engine still won’t start. If there is no other logical explanation or mechanical issue to explain why you’re having engine problems, then it could be associated with the wiring of the immobilizer inside your vehicle.

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Bad Wiring – If you are having problems with your immobilizer but your key is functioning properly, then you need to physically examine the immobilizer’s wiring inside the vehicle. If the wiring appears to have damage, wear, and/or corrosion, then this is a clear indication as to why your immobilizer system is not working. As a result, you will need to have all the wiring replaced. This can only be done at the car dealership where you purchased your vehicle.


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