Remote Key Won’t Unlock Car Doors: Here Are the Reasons and Fixes

Central locking is a great option that improves vehicle accessibility way more than people realize. Also, since it's such a common option and has been for at least two decades, people take it for granted, and only when problems appear will they realize just how good this option was. After all, it's quite easy to understand why it's so common. Only having to press a button on the key fob to unlock the doors is way easier and faster than having to unlock each door manually.

In this article, we are going to talk about why the remote key doesn't unlock the car doors anymore, more specifically which are the causes of failure, how to fix it, how to prevent it, and if this means that your vehicle is easier to steal.

Why won't the remote key unlock the car doors?

If you find yourself in this situation, you should know that there can be many possible causes for this problem and it's not always the key fob that's faulty. Here are a few reasons why your remote key might not unlock the car doors anymore:

1) Bad key fob battery

This is one of the most common reasons why your car's remote key might stop working all of a sudden. The key fobs have batteries and they need changing from time to time whenever these batteries go bad, pressing any button on the remote key will simply not do anything. One way you might tell that this is the actual problem is if you can manually unlock the door by inserting the physical key into the door lock.

2) Desynchronized key fob

Electronics can be a little bit temperamental, which is what might have happened in your case. Sometimes, it happens that the key fob desynchronizes with the immobilizer or central locking module and when this happens, pressing buttons on it will do exactly nothing. If the little LED on the remote key lights up whenever you press a button, you know that the battery is still good, but you will only be able to unlock your vehicle manually.

3) Bad car battery

A bad car battery will almost certainly mean that your central locking will not work, since all of the electronic equipment of the vehicle needs electricity to run. If you try to unlock the doors manually, yet twisting the key into a certain door lock only unlocks that specific door, you know what the issue might be. This problem will be a lot more obvious if you try to start the vehicle or turn on the headlights and nothing happens.

4) Blown central locking fuse

The fuse related to the central locking might have blown, in which case the central locking will not work and therefore, pressing a button on the remote key will not do anything.

5) Faulty key fob

Remote keys are electronic components and, if you think about it, you use them every single time you want to get in your car, so they see a lot of use. With time, they will eventually stop working, especially if they have been dropped multiple times or simply exposed to physical damage.

When the key fob itself goes bad, your vehicle might not even start anymore if it's equipped with an electronic immobilizer, since the immobilizer won't be able to recognize the key. If you happen to have a spare key that works just fine, then we believe that you probably know by now what your problem is.

6) Door locks lacking lubrication

Even though most vehicles out there have electronic door actuators, you should know that the actual door locking mechanism is still a mechanical component and, as you might know, such components need lubrication to work as they should. Because of time or water intrusion, this lubrication might not be good enough for the doors to unlock properly.

7) Bad door actuators

Electronic door actuators can fail too, especially if you think about the fact that they are located inside the doors, which are slammed every time someone gets in and out of the vehicle. These shocks will definitely affect their lifetime.

8) Bad wiring/connectors

Faulty wiring or connectors are some of the most annoying problems out there since they usually take quite a lot of time to troubleshoot. Sometimes, a split wire will take many hours to find and even though the fix itself is usually quite easy, the amount of work necessary to find that specific broken wire is quite a lot.

9) Faulty central locking module

Like most important systems in your vehicle, the central locking has a module too, which is what basically commands the doors to lock and unlock whenever you press the button on the remote key. If this module fails because of age or physical damage, the central locking will certainly stop working and you will be able to unlock only one door at a time.

10) Bad comfort module

The comfort module in your vehicle is used to operate many other options, such as the electric windows, the lights, and, of course, the central locking. When these modules fail, you will notice all sorts of strange problems, such as windows that don't go up and down anymore and central locking that will not work as intended.

How to fix the problem?

Fixing the problem must first begin with a thorough troubleshooting process. When it comes to electrical issues such as this one, you should always start with the easiest stuff, working your way to the more difficult and time-consuming possible causes.

If simply replacing the key fob battery, trying to resynchronize it (procedure usually described even in owner's manuals), or replacing a fuse doesn't fix the issue, we would recommend you perform a diagnostic. Cars nowadays are very sophisticated when it comes to electronics and since the central locking has its own module, certain problems can be noticed when performing a diagnostic, which will give you some error codes that you can interpret to tell what exactly has gone wrong.

Faulty modules will usually need coding as well, which is why we would recommend you ask for a specialist's help if you don't have the possibility and knowledge to do this yourself.

If the key fob is faulty, you should know that your local dealer will be able to help you in this situation. You can buy a brand-new key fob which they will program to work with your specific car. Also, these days there are many other specialists out there that deal with this sort of stuff, if, for some reason, you don't want to go to the dealer.

As we've mentioned earlier, bad wiring can take a lot of troubleshooting, which is why we would recommend you take your time and be very patient if you decide to do it yourself. If you take your car with this issue to a specialist, you should expect quite an expensive repair bill, since the troubleshooting process might take a very long time.

How to prevent issues in the future?

Apart from replacing the battery of the remote key every once in a while, or as soon as you notice that it's acting up and avoiding damaging it there really isn't much you can do to prevent issues such as this one. The remote key itself and the central locking system aren't components that drivers usually mess with, which is why very few times do they fail because of driver error.

This is one of those situations in which when things no longer work it's simply because of age and use, which is something you should always expect, especially if we are talking about an older vehicle. Luckily, these issues are almost always fixable and you shouldn't be too alarmed by such problems.

Is your car easier to steal now?

No, you shouldn't worry too much about this if you can manually lock each door and the trunk. Central locking means that if one door gets unlocked manually or if you press a button on the remote key, all of them will unlock. That's it. Door locks have been fitted to cars for a very long time, it's only this comfort and accessibility feature that has been added later.

Going back to the question, the car will be just as easy or difficult to steal as it was before. The only thing that changes is you have to lock and unlock each door manually. However, forgetting to unlock one of the doors will almost certainly make the car easier to steal.

Final thoughts

Having a remote key that no longer unlocks the doors can be quite frustrating, but these days such problems are usually fixed quite easily since the technology has gotten to a point in which troubleshooting is a lot easier than it was in the past.