Cluster cars
The cluster holds the immobilizer data. Swapping a used cluster without transferring data leaves the car unable to start.
MQB
Common on VWs since the mid 2010s. More steps than older cars, done at the car.
MLB
Mostly Audi. The key data is in a body module; for all keys lost it's often read on the bench.
Written by Key Monkey, European car key specialist in Marietta, GA. Updated October 23, 2026.