Transponder key programming, done where the car is

What this covers

A transponder key looks like a plain metal key, but its head holds a small chip that the car reads before the engine is allowed to run. Transponder key programming teaches the car to recognize a new chipped key, so the key both turns the lock and starts the car. It is what a key needs after it has been cut, whether it is a spare or a replacement.

How we approach it

We cut the blade to match the car's locks, then program the chip to the car where it is parked. The test is simple and it is the one that matters: the key has to open the door and start the engine. We check both before the job is finished, and if you have other keys for the car, we check that they still start it too.

Where it stops

Programming covers the key and its chip. If the car refuses a correctly programmed key because of a fault in its wiring, its battery or its security electronics, that is a job for a mechanic or a dealer, and we will tell you what we found. We also do not program a key for any car without proof of who owns it.

The clearest sign of a chip problem is a key that turns the ignition but does not start the car, sometimes with a flashing key symbol or a security light on the dashboard. That points to the car not recognizing the chip, not to a broken ignition. It is also what happens with a copy cut without programming: the blade is right and the chip is not.

A chip can be damaged without any sign on the outside. A key that has been dropped hard, put through the wash or crushed in a pocket may still look perfect and still turn every lock, yet the car no longer reads it. If one of your keys starts the car and another does not, the difference is most likely in the chip, not the blade.