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Lock Blog

A resource for consumers, locksmiths, and security professionals

How To Reprogram Car Keys That Are Already Programmed

by Ralph November 7, 2022

You have a car key, but it is already programmed. So how do you get this programmed key to work with a different vehicle? There is a lot to unpack with a topic like this, including whether or not it is possible to reprogram your car key.

There is quite a bit to cover on this topic. And for the fullest experience, you should certainly read everything. But if you are in a rush, feel free to jump to the section that best aligns with the information you are looking for. Just be sure not to cut too many educational corners and end up making a programming error.

On the topic of car key reprogramming, we will cover the following:

Can You Reprogram Car Keys When They Are Already Programmed?

Yes, it is possible to take a car key that is already programmed and reset it to work with a different vehicle. However, there are limitations you will encounter with certain makes and models. It mainly comes down to how the electronics are designed on the key.

On top of the design, the electronics have to be working properly in the replacement key. If you have to reprogram car keys, that means it is a used key by definition. If it is used, it has the potential to be damaged. Damage or loss of functionality is one of the main dangers of aftermarket electronic car keys.

Requirements To Reprogram Car Keys:

  • The key must be designed for your vehicle’s make, model, and year.
  • All electronics must be in working order.
  • Keys cannot be designed to prevent reprogramming.
  • Self-programming almost always requires a spare car key.
  • Certain luxury vehicles only allow dealerships to program keys.

Car Keys That Need To Be Reprogrammed

Electronic car keys have gone through two main phases. The first is a blend of physical and electronic known as transponder keys or chip keys. And the most recent trend is to make the key completely virtual with the use of a car key fob, which has no blade.

But whether you need to replace a car key or remote, we will give a brief description and overview of these two main key types, so you understand them a little better. For example, see the difference when you reprogram car keys versus programming and replacing car remotes.

1. Transponder Car Keys

If you have an ignition key with a metal blade, take a look at the bow of the key. The bow is the wide circular or rectangular part you grip to turn the key when it is inserted. Sometimes the bow has a car key remote built into it, other bows will have a plastic cover (most often black).

The transponder chip for a key will be placed inside one of these bow covers. Therefore, these covers are the best visible indicator that you will need transponder key programming if you are replacing this type of key.

2. Car Key Fob

If you have a car key fob to start your vehicle, you don’t need to look at the key. Rather, take a look at your ignition. If it is a push to start button rather than a keyhole, then you know you are dealing with a key fob. But it can be trickier to reprogram car key fobs because they have more potential security controls.

Car key fob replacement is already more restricted by auto manufacturers with less access to new parts and programming equipment. But there are even certain companies that keep existing fobs from being reprogrammable. Some key fobs can only be programmed once.

Reprogram Car Key With Transponder Chip

The first issue you are going to run into has to do with transponder keys that physical keys that are already cut cannot be recut. And as a general rule, transponder keys have to be cut to fit an ignition before they can be programmed.

For this reason it is difficult to lower the cost of car key duplication by purchasing used parts. Certainly, in almost every case, you can avoid paying the dealership prices for your new car key, but you can’t trust online sources for parts as readily.

But for the sake of argument, say you have a transponder key that was programmed without being cut (which is possible, though unlikely). Here is the general process you would use to reprogram a car key with a transponder chip.

Steps To Reprogram Car Key With A Spare:

  1. Refer to the owner manual for the specific process for your vehicle.
  2. You will insert the working spare key into the ignition.
  3. Manipulate the working spare key until the car enters programming mode.
    1. Doors may need to be opened and closed.
  4. Programming mode will be denoted by the locking of car doors, flashing dashboard readouts, or some other visual or sound to show the process worked.
  5. Insert the new key (currently not programmed properly).
  6. Manipulate the new key as directed by manual.
  7. Exit programming mode
    1. Often done by removing the key.
  8. Test the new key.

Steps To Reprogram Car Key With NO Spare:

  1. Call a locksmith.
    1. This will be cheaper than the dealership.
  2. The locksmith can procure a key blank or program one you provide.
    1. They can only guarantee products they provide will work.
  3. The key code to get the right blade gloves can be gathered from the VIN or by decoding the ignition cylinder with specialty tools.
  4. Locksmiths will access your car’s onboard computer.
  5. After plugging into your car, new keys can be programmed, removed, and re-programmed.

Reprogram Car Key Fob

As long as the electronics are functioning, you can reprogram car key fobs that are already programmed. With a key fob not working, there is a completely separate problem. And if you are not able to program a key fob, the reason might be because there is damage to the electronics.

The most important thing when you want to reprogram car key fobs is that the fob corresponds to your make, model, and year. There is quite a bit of crossover between vehicles with the same year, but you cannot trust that everything is going to work.

Double-check your part numbers before purchasing a replacement key fob. You will not positively affect your key fob replacement cost if you end up spending money on parts that don’t end up working.

Steps To Reprogram Car Key Fob With A Spare:

  1. Look to see if your car has a self-programming procedure.
    1. With cars made after 2010 or luxury manufactures, this is exceedingly rare.
  2. If the car has a self programming method, refer to documentation for specific methodology.
  3. Without DIY programming, use a code capture device.
  4. With a working remote, you can capture the signal and program it to your new remote.
  5. If you do not have access to a code capture device, call a locksmith.

Steps To Reprogram Car Key Fob With NO Spare:

  1. Call a locksmith.
  2. A locksmith can advise you on which key fob you need.
  3. Once you have the car key fob you want to reprogram, the vehicle must be opened.
  4. With the car open, the onboard diagnostics port can be accessed.
  5. Special electronics will be used to make the car program the new key.
  6. If no locksmith in your area has access to the equipment you need, the dealership will be the only other option.

Why Do Car Keys Need To Be Programmed?

In the lead-up to the 21st century, car keys started to blend electronic and physical protocols to prevent theft. Ignition keys, up to this point, were just like house keys. The key was a simple piece of metal with grooves that corresponded to the internal components of the cylinder (often wafers).

Having standard keys made car key replacement very simple. It would only involve car key cutting, with the one complication being having no spare key to duplicate. But a locksmith could get your key code from your VIN (vehicle identification number) or by decoding one of the locks.

The simplicity made getting a new car key easy, but it also made theft easy. All a criminal would have to do is use a screwdriver or slide hammer and get your ignition cylinder to rotate. With the use of electronic components, you need a secondary digital code that is wirelessly transmitted along with the key’s rotation.

Security improved for modern cars. But the side effect of this added complication is that now you have to worry about locksmith car key programming costs, as this work is becoming nearly impossible to do yourself. However, there are many early iterations of the technology that allow you to reprogram car keys.

Who Offers The Best Car Key Reprogramming Near Me?

A car locksmith is going to be your best option to reprogram car keys. The main reasons are convenience, skill, and price. In some cases, you have to use the dealership because they have restricted access to key blanks and electronics.

The DIY methods to reprogram car keys will nearly always need a spare car key to get the new key working properly. And it is becoming rarer and rarer for it to be possible to reprogram car keys yourself. And in some cases, programming will be so restricted that only the dealerships can make new keys.

Closing Thoughts

At the time of writing this article, it is possible, more often than not, to reprogram car keys that are already programmed. There are, of course, exceptions to this general trend, so consult with your local locksmith before moving forward with transponder or car key fob reprogramming.

A locksmith offers replacement parts, programming services, and the peace of mind that everything will work. For the best results when you want to reprogram car keys, do yourself a favor and contact a locksmith.

Category: Automotive, Buying Guides, Car Keys

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