When your car won’t start, you may think your ignition or battery has died, but it’s possible the problem is your key. Transponder keys have microchips embedded in their heads, which send signals to the car, telling the ignition to start. This guide takes a closer look at these devices and what to do if one is faulty.

How Do Transponder Keys Work?

Transponders are part of your vehicle’s anti-theft system. When the key is inserted into the ignition, it sends a code to the car—if the car recognizes the code, it turns the vehicle on. Some have a resistor inside the head, and the car checks to make sure the right amount of resistance is registered when the key is inserted. Others use a rolling code, in which the key sends a numerical value to the car, the car decodes the message, alters the number, and sends it back. The key verifies the new number and starts.

Steps to Take If It Stops Working

Some keys have batteries, which can die. At other times, a high magnetic field can disrupt the chip's circuits. In either case, you may need to reprogram the key. Although some car manufacturers provide these instructions in the vehicle’s manual—usually so you can make clones to share with family members—many people call on a locksmith to perform this task for them. 

There are two main types of transponder keys—zero bitted and encrypted. The first allows locksmiths to make clones of your key anywhere they have access to their equipment. Encrypted keys require the locksmith to connect to your car to make a unique replacement specific to your vehicle.

If your car won’t start and you think your transponder key is to blame, trust the qualified locksmiths at One Call Lock & Key to help. Based in Driftwood, TX, they provide a wide range of services throughout Austin and the surrounding areas. Visit them online for more information on their services—from making spares to helping with lockouts—or give them a call at (512) 353-1112 to request service.