Transponder Key vs. Regular Key: What the Chip Changes

At first look a transponder key may be indistinguishable from its metal counterpart, however the crucial distinction lies hidden under the plastic housing of the former – in a microchip that communicates with the car’s immobilizer, as small as the chip might seem, it significantly changes the way the ignition works, the process of creating a spare, and, consequently, the price tags on all of that.

Functionality of a transponder key

Once you insert a transponder-equipped key in the ignition switch, the chip inside begins sending a code that must be acknowledged by the car’s immobilizer for the engine to start working. The blade of the key is not enough anymore; otherwise, no starting will occur.

Identify which key you have

All cars manufactured within the last twenty years use either transponder or smart keys, an indicator of the former type is that even a perfectly-cut key fails to start the engine, whereas the doors open without any trouble.

Differences in the replacement process

Cutting alone will not do for a new transponder key. You need one to be programmed in order for the chip to communicate correctly with the immobilizer. Programming is why there can be such variation in prices; read about that in our post What Makes a Key Replacement Costly?

What happens when the chip fails

Should the doors open, while the engine fails to start, most probably, the problem is with the transponder, not with the remote. Check out our guide to distinguish them in Fob Troubleshooting.

Upside of transponders

It is nothing new to deal with transponders in a mobile locksmith company. We program and cut your keys right at your car during the car key replacement procedure.