Here at AJT Installs, we realise that not everyone understands what immobilisers are and how they work. So, we thought we would put together a guide to immobilisers, to explain a bit more about them, how they work, how they can affect car insurance premiums, and how to make sure your car has that extra level of security they provide.
For even more expert advice on keeping your vehicle safe, as well as checking whether your car is one of the most stolen in the UK, you can download our FREE guide from the AJT Installs homepage.
What are immobilisers?
In a nutshell, they protect your car from being hot-wired or driven away without the proper key and are activated as soon as the ignition is turned off.
In the UK, it has been mandatory to install a factory-fitted immobiliser in every car manufactured since 1998.
So, what is it?
An immobiliser is a two-part electronic device.
The first part is a transponder located inside the ignition key fob, while the second part is a receiver in the Engine Control Unit (ECU), of your car.
If someone tries to start your car, a signal is transmitted to the key, and the engine will only start if the key returns the correct encrypted code to the ECU.
However, if the code is not the right one, the immobiliser will not send the engine the signal to start.
Therefore, if thieves try to steal your car without using the correct key, the immobiliser will prevent them from stealing it, unless they winch it on to a transporter.
Early immobilisers sometimes used a second fob rather than the ignition key, a button inside the car, or even a keypad with a four-digit code.
Today, most cars use keyless technology to open the doors (and start the engine in some cases), but the immobiliser still requires the key to be close.
However, in some cases, a smartphone is preferred to transmit the signal to the ECU instead of a key.
Another major change with modern day technology is that immobilisers use different codes each time, compared to twenty years ago when they used just one code for the whole life of the vehicle.
How do immobilisers work?
The device controls three things in the engine of your car through the ECU:
- The starter motor
- The fuel system
- The ignition system
The correct code is required before all three of these engines systems can be engaged.
If the immobiliser does not receive the correct signal from the key, or one of these three systems is bypassed in some way (like the ignition system in a case of hot-wiring), the car will not receive the signal to start from the ECU.
A guide to immobilisers: Does my car have an immobiliser?
You can find out whether your car has a factory-fitted immobiliser by checking the vehicle handbook.
However, if you bought a second-hand car, the immobiliser could be out of action for several reasons:
- The car could have been repaired or had replacement parts fitted that affect the starter motor, fuel system or ignition system. These replacements may have different data or affect the coding sequence.
- Key information has been lost through a battery replacement in the fob.
- The key has been incorrectly programmed – this can happen with replacement keys.
- An electrical fault has caused a malfunction or blow-out inside the ECU.
- Faulty coding in either the key or the device.
Even in cases where there isn’t a factory-fitted immobiliser, previous owners could still have fitted a replacement.
If you did not receive any information about the immobiliser from the previous owner, it is worth getting a qualified mechanic to check your car to make sure it has a working device fitted.
Can immobilisers malfunction?
Well, yes, of course they can.
Although it is a rare occurrence, you have to remember that it is an electrical device, so on occasion, it may fail.
The first tell-tale sign is that you experience problems locking and unlocking your car.
Secondly, the alarm may go off repeatedly and for no reason.
And the final clue is that your car just won’t start!
The most probable cause of a malfunction is a dead battery in the key fob, which is very easily fixed.
In the more unusual case of an electrical fault, you will need to get your vehicle checked over by a qualified mechanic, or the dealership where you bought your car.
Types of immobiliser
As we have already mentioned earlier in this guide, a factory-fitted immobiliser has been installed in new cars during manufacture since 1998, which has enabled the device to be incorporated into every vehicle’s electrical system.
If your car:
- Does not have a factory-fitted immobiliser
- You are worried that the immobiliser in your car has old technology and may easily be hacked
- You want to upgrade your car security system because of new threats…
talk to the experts at AJT Installs to discuss the options for after-market immobilisers or visit our website.
Today’s technology means immobilisers can use blue-tooth connectivity, and the latest Ghost CAN bus immobiliser protects your vehicle via a PIN code.
This means that even if thieves clone the key to your car, they will be unable to drive it away.
A word about Thatcham Research
Founded in 1969, Thatcham Research provides an assessment and certification of car security systems, both factory-fitted and after-market.
It does this through research, tests, and the evaluation of the safety and security of new vehicles.
Because it is so widely trusted by both manufacturers and insurers, its certification for vehicle security systems have become a benchmark in the motor industry.
This is why you will see ‘Thatcham approved’ on many vehicle security devices.
It gives you, the consumer, that extra peace of mind when buying a car security system, that it has been thoroughly tested and rated by Thatcham Research.
There are seven different categories covering:
- Alarms with immobilisers
- Immobilisers
- Upgrades or after-market alarms
- Mechanical deterrents and devices such as steering wheel locks and gear clamps
- Wheel locks
- Tracking devices
- Location devices
You can read more about Thatcham Research and their security assessments on their website.
Insurance premiums
Immobilisers make cars more secure and harder for thieves to steal, resulting in a reduced risk to insurance companies.
In fact, factory-fitted immobilisers are often listed as options when taking out a policy, but you should always bear in mind that different insurers may evaluate risk differently.
If you have installed an after-market security system in your car, or you use other mechanical deterrents like a steering lock, it is always worth having a conversation with your insurer to see whether you can bring the premium down further.
An immobiliser can be an effective device against theft, but even more so when combined with other precautions:
- Electronic security devices such as car alarms, tracking devices and dashcams
- Parking your car in a garage or safe driveway with parking posts, locked gates, and CCTV
- Using physical deterrents such as wheel locks, steering locks and gear clamps – you can read more in our blog about steering wheel locks
- Don’t leave valuables or your vehicle documents in your car
We hope that you have found our guide to immobilisers interesting and informative. However, if you are worried about vehicle security, talk to the AJT Installs team of fully qualified and insured vehicle installation specialists about our range of Thatcham approved alarms, immobilisers and tracking systems, along with dashcams and parking posts. We pride ourselves on providing a professional installation with a friendly touch, to make sure your car has the best level of protection and security for your needs. Alternatively, you can find out more about our range of after-market immobilisers on our website.