Why a used DME may not start the car
The engine computer and the vehicle’s security module exchange immobilizer/security data. If the replacement DME contains data from another vehicle, the required security values do not match and engine start can be blocked.
ISN and SK
Older BMW systems commonly use an ISN-based security relationship. Newer systems use longer security data often referred to as SK. The practical point for the customer is simple: the replacement DME must be correctly matched to the vehicle’s CAS, FEM or BDC environment.
Supported security modules
- CAS2
- CAS3 / CAS3+
- CAS4 / CAS4+
- FEM
- BDC
What we need
Send us the year/model, original DME details, replacement DME details and the current no-start symptoms. Depending on the vehicle and module condition, we will tell you which modules or data are required.