Key Programming: Keys, Codes, Diagnostics

Key Programming: Keys, Codes, Diagnostics

In the 1980s, the only thing standing between a thief and starting a car was the lock's tumbler. The thief could pick the lock or violently remove the lock's tumbler with a slide hammer. Re-keying a car involved installing a new lock cylinder – this is not the case with most late-model vehicles.

In the 1980s, the only thing standing between a thief and starting a car was the lock’s tumbler. The thief could pick the lock or violently remove the lock’s tumbler with a slide hammer. Re-keying a car involved installing a new lock cylinder – this is not the case with most late-model vehicles. 

By the late 1990s, almost every key included a radio frequency ID (RFID) chip in the body of the key or remote to stop car thieves. The ID number from the RFID chip sealed in a glass vial had to match the ID programmed into the vehicle. Now, with proximity key systems, the car starts without the turn of a key. This evolution is not an obstacle for your shop, but an opportunity. 

Key Programming: Why Not?

Three situations might require key programming capabilities at your shop. First, being able to diagnose and program keys can be a tool as part of some no-start diagnostics. Second, you may run into a situation where a key or fob needs to be reprogrammed to the vehicle if a module was replaced. Third, a customer might want an extra key or all the original keys were lost.

You might think that key programming is a job for a locksmith or specialist, but the market is changing. Brick and mortar locksmith and dealership parts departments can cut key blanks, but it is up to you to make them work with the vehicle. In the case of some proximity keys, there is no key to cut – it is all up to you.

Onboard Programming

For most vehicles you see at your shop, it is not as much about programming a key to the car  but programming the car to the key. Programing a vehicle to the key might require a procedure to put the vehicle into a learn mode; this is typically called “onboard” programming. 

Newer vehicles require a scan tool to learn a new key or remote to perform onboard programming. You might already do this at your shop if you have the right scan tool and software. 

Onboard procedures use the antenna coil on the vehicle to read the transponder or ID number in the new key or remote. The vehicle gets the key’s transponder to transmit, and the unique ID is learned by the vehicle during the procedure.  

PIN Codes

One of the changes made to some late-model vehicles is the requirement to have a three- or four-digit PIN code to perform onboard programming.  Chrysler, VW and other makes require PIN codes depending on specific model years. This code resides in the module for the immobilizer system. 

You can contact the OEM for the code or in some cases it might be found in the owners manual in the glove box if you are lucky. But, some key programming tools can harvest the PIN code from the modules.

Programming Keys

To increase security, some OEMs are requiring the key to transmit more than just the ID code. VW and other European manufacturers are requiring that the key transmits the unique VIN of the vehicle. Specialty key programming tools can program the transponder code and VIN onto a key.  

Reflashing and Reprogramming

Data can go both ways when it comes to some key programming tools. Information from a key can be programmed into a module, or information from an existing module can be programmed onto a key. This tool function can save you if a module has been replaced or reflashed and the key information is lost. It is also helpful if you are in a situation where all the keys have been lost. 

For situations like this, you have several options. Some key programming tools and vehicles will allow you to clone key transponders in the memory of the vehicle. The programming tool communicates with the vehicle to find the information about existing keys and then burn that code to a new transponder using a specialized attachment for the key. 

On some vehicles, the situation may call for reflashing completely new transponder codes to a module. For some cars, this can be performed through a J2534 interface. Other cases may require the module or EEPROM chip to be removed for reprogramming.  Specialized key programming tools let you do it at your shop. 

The key to a modern vehicle is more than a key. Modern keys and fobs can start a vehicle remotely, open a rear hatch with a swipe of a foot, and make sure the vehicle is secure against physical and virtual attacks. If you are already servicing these vehicles, you can’t – and shouldn’t – avoid key programming. 

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