open car key fob

How to Start a Car With a Dead Key Fob

In Electric by Magnus Sellén3 Comments

The automotive industry is getting its fair share of modernization.

We have technology such as parking sensors, keyless entry, automatic windscreen wipers, and much more! This really is the age of technology. But no matter how advanced the technology is, there are limits to its functionality. What good is advanced technology if it is vulnerable? What good is a key fob if it doesn’t work and you’re locked outside your car?

Fortunately, there is a solution to this problem. We will tell you how to get around a dead key fob.

How to Start a Car With a Dead Key Fob

1. Replace the batteries

dead key fob

So your key fob doesn’t work. What do you do first? Well, obviously, you check the batteries. The key fob can’t work if the batteries are dead or malfunctioning. If you are at home, changing the batteries is an easy task, as you have spare batteries at home.

However, if you are stranded away from home, replacing your old batteries with new ones can be problematic, so you should always carry spare batteries in your car. The fob is assembled with a screw that you need to unscrew to remove the batteries. It has a small battery like the ones found in watches.

2. Open the Door Manually

As a last resort, you can try to unlock the door manually. However, this is only possible for vehicles that have a key to the door. You cannot use this method for a car with keyless access. It is best to pray that your keychain has enough power to pry the door open.

Some cars have a the lock hidden under a plastic piece which you might have to remove before you can unlock the car manually.

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To test this, you will need to press the key fob against the door and then try to open it. This might work, but you will probably need to replace the fob’s batteries.

3. Remotely Open the Vehicle

Some manufacturers have tried to protect their customers from this problem by offering a service that allows the car owner to remotely access his car. All you would have to do is to jump on the special app on your smartphone and signal the service department of your predicament.

They will open the car for you upon inspection and in some cases even start the engine for you. All major manufacturers like BMW, Audi, Alfa Romeo, Chevrolet and Ford have this feature.

4. Starting the Engine

Once you are in your car, you must try to start your car. Keyless access works with the same key fob that you use to unlock the doors. If that doesn’t work, you’re in big trouble. Fortunately, car manufacturers have realized that a key fob can fail at any time, so they have a fail-safe device just in case. The keyless entry system is designed so that the car can be started manually even if the key fob fails. Some manufacturers also offer a spare key in the key fob that can be used to start the engine.

You may not have noticed, but even in vehicles with keyless access there is a slot behind which a key slot is hidden. A plastic cap hides this slot, but it can be snapped off if you need to start the car manually with the emergency key. For cars with a start button, you can press the key ring against the button to start the car, apply the brake and press the button. You may have to repeat this procedure a few times before nailing it down. Every car is different, so always read the instructions that come with your car when you buy it. Such important information can only be found in the owner’s manual.

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How does a key fob work?

The key fob is an interesting piece of equipment. The key fob usually sends a specific code to the receiver in the car. This code is specific to each car, otherwise, anyone could unlock and start your car with their key fob. There are ways to capture the code transmitted by the key fob, but it is not easy. The car companies take the security of your car very seriously and have therefore developed modern systems to prevent theft.

The transmitter of the key fob sends a 40-bit code to the car, which is generated by the controller chip. The car system recognizes the code and performs the appropriate function such as unlocking the doors or starting the car. The key fob only works when you are in the car’s working area. If you are a few meters away, you will not be able to unlock your car, no matter how often you try.

This is a great measure of security. If a person does not have exactly the key fob you have, they cannot unlock your car. Even hacking into the system is not easy, because the transmitter sends a 40-bit code that can be one of a trillion possibilities.


So what is your best bet when it comes to starting your car with a dead key fob? The answer is simple. Whatever works best for you! A dead key fob is not as complicated as you might think. It can be solved in less than five minutes, and you don’t need outside help from a mechanic or technician to help you. As for tools, you don’t need much. You can even improvise with a coin to open a key fob and replace its batteries.

The silver batteries in a key fob are the same batteries found in a wristwatch. Replacement batteries are easily available in a watch shop or you can go to the nearest department store to get them. It is also important to note that in most cases you will not even need to replace the batteries. You are not completely hopeless if the battery fails and the key fob dies. It is built to adapt to such situations.

3 thoughts on “ How to Start a Car With a Dead Key Fob ”

  1. Hello can you please contact me at soon as possible. I have a Dodge Durango 2012 and a key fob that no longer starts my car. When I put the key fob in the ignition and turn it to on a message reads damaged key. What do I need to do to avoid major costs? If I take it to a dealership can they just reprogram it simple as that? I’m so frustrated and I’m thinking the power chipboard that’s inside the key fob may be damaged. Any suggestions or advice?

    1. My Nissan 2014 370Z key fob died.
      I replaced the battery but it still won’t start.
      Is there anything I can do?

  2. How do I know that it’s not a scam and steal my bank information, then the inconvenience that I have to go thru.

  3. Due to very high demand and a high amount of comments, you might have trouble getting your comment answered by me. If you want to get fast answers from a certified automotive technician you should ask your questions here: Ask A Mechanic

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