dead key fob

How to Start a Car With a Dead Key Fob

In Electric by Magnus Sellén3 Comments

dead key fobThe automobile industry is getting its fair share of modernization.

We have technology like parking sensors, keyless entry, automatic windshield wipers and what not! This is truly the age of technology. But no matter how advanced the technology, there are limits to its functionality. What good is cutting-edge tech if it is vulnerable? What’s the use of a key fob if it doesn’t work and you are locked outside your car?

Fortunately, there is a workaround to this problem. We will tell you how you can work around a dead key fob.

1. Replace the batteries

So your key fob is not working. What’s the first thing you do? Well, obviously you check the batteries. The key fob cannot function if the batteries have died or if they are malfunctioning. If you are at home, changing the batteries is an easy task given that you have spare batteries at home.

However, if you are stranded away from home swapping your old batteries for new ones can be troublesome, which is why you should always keep spare batteries with you in your car. The fob is put together using a screw which you would have to unscrew to take the batteries out. The key fob has a small battery like the one you find in watches.

2. Open the Door Manually

As a last resort, you can attempt to unlock the door manually. However, that is only possible on vehicles that have a key for entry. On a car, with the keyless entry, you won’t be able to apply this method. Your best bet would be to pray your key fob has enough power to pry the door open.

To test this you need to press the key fob against the door and then attempt to open it. This might work but chances are you would have to swap the fob batteries.

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3. Remotely Open the Vehicle

Some manufacturers have tried to safeguard their customers from ever facing this problem by providing a service that lets the vehicle owner access their car remotely. All you would have to do is hop on to the dedicated app on your smartphone and signal the customer care department of your fix.

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

4. Starting the Engine

Once you are inside your car you have to try and start your car. Keyless entry works through the same key fob that you use to unlock the doors. If that is not working you are in big trouble. Fortunately, automobile manufacturers realize that a key fob can fail anytime and as such, they have a fail-safe just in case. The keyless entry system is designed in such a way that if the key fob dies the car can still start manually. Some manufacturers also provide a spare key in the key fob which can be used to ignite the engine.

You might have not noticed but even in keyless entry vehicles, there is a slot hidden behind which is a key slot. A plastic cap hides this slot but it can be popped off in case you need to manually start the car using the emergency key. In cars where there is a start button, you can press the key fob against the button to start the car, press the brake and push the button. You might have to repeat this process a few times before you nail it. Every car is different, so always read the user manual you get with your car when you buy it. Such vital information is only available in the user 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 particular code to the receiver inside the car. This code is specific for each car otherwise anyone would be able to unlock and start your car with their key fob. There are ways to capture the code transmitted by the key fob but is not easy. Car companies take your car’s security very seriously and so they have developed modern systems that prevent theft.

The key fob transmitter sends a 40-bit code to the car that is generated by the controller chip. The car system recognizes the code and performs the relevant function like unlocking the doors or starting the car. The key fob works only if you are within the working range of the car. If you are a few meters away you won’t be able to unlock your car no matter how many times you try.

This is a great measure of security. Unless a person has the exact key fob you have he/she cannot unlock your vehicle. Hacking into the system is also not easy since the transmitter sends a 40-bit code which can be made up 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 an issue as you might think. It can be solved in less than five minutes and you do not need any external help from a mechanic or technician to help you with it. In terms of tools, you don’t need much. You can even improvise with a coin to open up a key fob and replace its batteries.

The silver batteries found in a key fob are the same batteries you would find in a wristwatch. You can easily get replacement batteries from a watch shop or you can visit the nearest departmental store to get your supplies. Furthermore, it is important to note that in most cases you don’t even need to replace batteries. You are not completely hopeless if the battery fails and the key fob dies. It is built to adapt to such situations.

  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 a very high demand and high ammount of comments, you have to wait for some time for your car questions to get answered. If you want to get fast answers from a certified master technician you can ask your questions here:
    Ask A Mechanic

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