How Do I Find My Immobilizer Code? When Do You Need It?

Immobilizers have been present in most vehicles for a few decades already and they have been very useful in preventing theft and unauthorized starting of the vehicle. Most people take this for granted, but if we think about the old days, pretty much anyone with a basic set of tools and a little bit of ingenuity could simply get into a car, start it and leave with it. No errors, no alarms, no nothing.

Car software problems highlights

• Howcommon:very common
• Main reasons:glitch, voltage problems, hardware issues, wrong settings
• DIY diagnosis:complicated
• DIYrepair:sometimes possible
• Solutions:resetting, changing settings,re-pairingdevices
• Can you drive?yes
• Price in dealership:$150 - $400

How does the immobilizer work?

Immobilizers work in conjunction with the vehicle's computer, or ECU (electronic control unit), so before anything happens with or to the car, it must first go through the immobilizer.

You might have noticed that car keys in the last few decades have started to have buttons on them, that are used to lock or unlock and some other functions as well. Whenever a certain button on the key fob is pressed, it then sends a signal to the vehicle's immobilizer. If the key is recognized by the car's immobilizer, then the doors unlock. If not, nothing happens. This is why trying to unlock two identical vehicles with the same key will never work.

The clever technology doesn't stop just here. Although an immobilizer makes unlocking a vehicle more difficult, unfortunately, it doesn't make it impossible. Sometimes, people end up using brute force to unlock a car, in which case the clever key fob becomes useless. Or does it?

You see, entering a vehicle is only half the job since most of the time, thieves also want to leave with the car, and here's where their life becomes a lot more difficult. Even if they have an identical key to the one your vehicle uses, the immobilizer simply doesn't allow the engine to start, no matter what they do.

Immobilizers and key fobs have very specific and unique codes, which are difficult to copy unless there are special tools involved in the process. Some more modern immobilizers, even change these codes every time the car is locked and they are memorized only by them and the key fob of the vehicle. Quite clever, right?

Another great feature that some vehicles have is whenever someone tries to use a key that is not authorized to work with that specific vehicle, it will set off the alarm, making the potential thief give up whatever he was trying to do.

How do I find the immobilizer code?

As we've just mentioned above, every immobilizer has its unique code. This is used to pair it to the vehicle's ECU and key fob.

If you have asked yourself this question, you are probably interested in making a copy of an existing key. The thing is, finding the immobilizer code is not done by simply looking for it in the owner's manual, or by reading a tag on the immobilizer itself. This would have meant that anyone could have made copies of your car key.

There are a few ways to find this code, one of them requiring quite a bit of knowledge of what you're doing, so think twice before attempting to do something.

The easiest way to find your immobilizer code would be to visit your local dealer. In their database, they have a record of all the vehicles that have been sold and will therefore know about yours as well. Simply go there and tell them what you're there for. Don't worry, the dealer itself won't exactly know what your code is, but by using specialized software, they will make a copy of your key without that code ever being disclosed to anyone.

An important thing to keep in mind would be to bring with you the paperwork that shows that you are the actual owner of the vehicle. Otherwise, the dealer will be reluctant to help you in this regard. Even though they can't tell if you have stolen the car, they also can't tell that you are its owner either.

The second, and more difficult way, of finding the immobilizer code, would be to use special software dedicated to your vehicle. If you know where to look, you should be able to eventually find the code you're looking for. This isn't a particularly easy task, so it would be better to avoid messing with such things if you don't actually know what you are doing.

Another way, if for some reason you want to avoid going to the dealership, would be to ask a specialist who deals with immobilizers and key fobs. They will most likely have the dedicated software and tools to help you find the code or to make a few copies of your key.

Keep in mind that many times, copying a key fob could turn out to be quite expensive, even though you might find the complete keys for very low prices online. Programming them is actually a difficult part that can't be done by anyone.

When do I need the immobilizer code?

Going back to one of our main questions, there are a few times when you might actually need this code, even though it might seem something that you rarely, if ever, mess with.

Let's say you have lost one of your keys and you want to make another copy since it would be quite risky only having one key left. This is a situation in which you will need this code.

Also, if we're talking about lost keys, an important thing you should know is that while a specialist or the dealer can make copies of your key, they can also eliminate the lost key from the immobilizer's memory thus making it useless. This should make your sleep easier at night knowing that even if someone finds the key you've lost, they won't be able to do anything with it.

Sometimes, replacing components such as the ECU or TCU (transmission control unit) might require pairing with the vehicle's immobilizer, which would be another situation that would require you to know the immobilizer code.

We recommend you only go to trustworthy specialists when it comes to key fobs and immobilizers since anyone who might have a "cheaper solution to your problem" could actually turn out to be just someone who wants to know more about your car's safety systems than they should.

Can my car still be stolen?

Unfortunately, yes. Although immobilizers have become very clever in the last few years, they are still not 100% safe. The bad news is that they are not the only ones that are more modern these days, but also the various devices that have been invented with the sole purpose of cracking immobilizers and copying keys.

Nowadays, you can find such devices even online, which makes this entire process easier than it might have seemed at first.

Now, don't get us wrong, this doesn't mean that your brand-new vehicle is just as easy to steal as something made in the 1960s, but it also isn't exactly 100% theftproof.

One thing that might save you, would be to have your car keys put inside a closed metal box. This would prevent any signal to be replicated using special devices that are used to trigger key fob signals and then copy them.

Final thoughts

Things such as the immobilizer code and the immobilizer itself might seem quite unimportant at first since they are not components people usually mess with, but as soon as they realize what their purpose is and how important they are, they might start giving them a little bit more attention than they used to.

Also, knowing how they work and what they do, might lead you into doing a little bit more research regarding theft prevention and how to avoid having your key copied without your permission.