Why Does the BMW Key Won’t Open the Door? [Mysteries Solved]

One of the more sought-after features in BMW is the Comfort Access or keyless entry system controlled by the key fob. This sophisticated feature accommodates your busy life and keeps you free from carrying around a cumbersome key. However, it fails to open the door sometimes.

But why BMW key won’t open the door? A dead battery is the most common reason the BMW key fob won’t unlock the door. Nevertheless, there are some other reasons why it can happen. These may include faulty receiver modules or electrical circuits, pairing issues, faulty buttons, signal interruption, water damage, etc. 

However, we have seen two groups of victims: one can’t unlock the door, but the car is starting, whilst others can’t start the vehicle as well as can’t unlock it. Here the causes and remedies become diverse. So, let’s have an in-depth discussion on those causes, along with some quick fixes.  

BMW Key Won’t Open Door – Common Causes and Solution

When we’re talking about a key fob being unable to unlock your car’s door, naturally, we blame the key fob first. In fact, we have also indicated the same thing in the beginning. 

However, your BMW itself can also be responsible for the issue. More or less we’ll also discuss this fact as well. Now, let’s explain the most common causes of why a BMW key fob won’t unlock the door. 

Dead or Dying Key Fob Battery

Your BMW key fob runs on a coin cell battery. After a certain period of time (typically 3–4 years), this battery will be dead. The single most frequent cause of your BMW key fob not unlocking the doors is that the battery is dead or dying. 

So, if your BMW key fob fails to unlock doors and has lost all functionality, the first suspect would be a dead battery. 

In some cases, you may notice a significant decrease in your key fob’s functionality. This generally indicates a dying battery.

A dying battery is able to function erratically or may not have a strong enough signal to function at a particular distance. In contrast, a key fob becoming completely ineffective at all can be a result of a dead battery.  

In such cases, consult a technician. No matter if the battery is dying or completely dead, your mechanic may suggest you replace the battery first. 

Worn Buttons

Worn buttons can be problematic in any type of keyless entry system. Among the staple features of worn-out buttons is the failure of your key fob to work when you press the button multiple times or with too much force. 

For example, if your key fob continues to fail to unlock doors after you have pressed the button more times than necessary or applied pressure in an unusual way, this could be the issue.

In fact, you may discover some buttons are working as usual, but others don’t. Thus, your car keyless remote might be able to lock the door but fails to unlock it. 

The failing functionality of remote key fob buttons is among the clearest indicators that a key fob button is worn.

Damaged buttons and worn housings are absolutely good tip-offs for this problem. In some situations, practically all the buttons will drop out. Rather than purchase another remote, it is cheaper and more practical to replace the casing only.

Pairing Issue

Your key fob needs to be paired with the BMW for successful command and action. However, the pairing can be interrupted due to several causes, such as battery replacement. 

When that happens, the remote key of the BMW can stop working because the pairing has not been successfully completed. 

In this scenario, you’ll need to be aware of reprogramming the key fob of the BMW. You can use a scanning tool to reprogram the key fob. The reprogramming of the key is usually stated in the owner’s manual. 

Follow the steps presented in the handbook to pair successfully. The guidelines will be mentioned in the manual. If you don’t understand the process, you may need to go to a trusted specialist to have your key reprogrammed. 

Faulty Receiver Module

The BMW keyless entry system has a built-in receiver antenna that picks up signals from the remote. If you notice that your BMW door isn’t unlocking even after reprogramming the key fob, maybe the receiver module has problems. 

If your vehicle’s keyless entry antenna is malfunctioning, the sensor may not be able to correctly register whether the remote car control is triggered. So, it will likely be necessary to have another diagnostic check to determine the original reason. 

The faulty keyless entry antenna could have gotten damaged, or the electronic module of the vehicle might not be communicating with other security modules. 

For any of these issues, you can use an OBDII scanner to check the responses from the keyless entry system and determine whether the security module is transmitting and acting on the commands. 

Water Damage

Water is an open evil for any electrical components. With a standard BMW key fob, you should be able to use the device without worrying that short-term moisture levels may cause damage. By leaving it in your pocket during rain or accidentally dropping it in a pool, nothing ought to go wrong.

However, long-term wetting can cause permanent rust and corrosion which could render the key useless, perhaps even breaking the keypad. The battery could also fail or leak or explode, rendering a healthy key useless. 

The key being submerged in the ocean or the wet soil in your backyard can do additional damage to the key fob component because of how conductive salt water is.

Intense salt water exposure, soap, water, or dirty water can adversely affect the chip in directional components and require cleaning isopropyl alcohol or electronic cleaner. 

If the key fob’s functions have not returned following cleaning and thorough drying, the chip is probably damaged and will have to be replaced.


It’s common to have a lot more questions regarding a BMW key fob with door unlocking issues than we ourselves have answered. Hence, our FAQ item is intended for people searching for more information.

Can I unlock my BMW with a dead key fob?

Starting your car while your key fob is dead is a piece of cake in most vehicles. All you need to do is use the key to open the door and start your vehicle manually. Most automobile manufacturers incorporate manual unlocking to their vehicles to access the car even if the remote keyless entry system isn’t working.

Can you get locked out of a keyless BMW?

Yes, a BMW can be securely locked with the key fob inside the car. You can do so deliberately if you have to choose a location to protect the fob in the event of a robbery or accident. It is also possible for your fob to fall out of the car unintentionally. Such a situation can be solved in several ways.

How do you manually unlock a BMW?

Press the button (release button) at the rear of your key fob. Pull out the blade, then proceed to locate the door keyhole. Insert the key blade in its opening, and push the latch lever off the top. To open the door, insert the key blade into its opening and then push down the latch lever.

How do I reprogram my BMW key fob push to start?

Press down on the unlock button of the BMW key fob and take hold of it while pressing down on the BMW logo three times. After that, release the unlock button.
Once again, you have to lock and unlock the door.  If you see everything is done without any issues, the key will be reprogrammed automatically in the meantime.

Final Words

It’s quite common to encounter a situation where your BMW key won’t open the door. This common but extremely irritating problem can be your major annoyance unless you have a bit of knowledge we shared above. 

Even if you see the door isn’t unlocking, don’t rush to purchase a brand-new key fob. Rather, talk to a skilled person or mechanic about whether there is another way. Try to reprogram the key fob after replacing battery.

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