Whenever you exchange a broken ECU or handle an all keys lost situation you need to read the ISN from the DME.

• When you exchange the DME/DDE – you have to write this DME ISN to the CAS.

There are two CAS types

1. CAS unit without encryption - in this case you need to read the ISN of the DME/DDE and write it in the CAS ISN field by copy-paste it followed by click on the pencil icon on the right hand side.

2. CAS unit with encryption - in this case you need to read the ISN if the DME/DDE, write it in the CAS ISN field by copy-paste it followed by click on the pencil icon on the right hand side and click on Encrypt CAS ISNs.

• It is recommended to Synchronize the CAS with the DME from “Keys and start synchronization > Synchronize CAS&DME “ and disconnect the car battery for 1 minute.

Important notes

• If the car is immobile after this with a tampering fault, see 17.4 EWS Tampering DTC.

• Reading the ISN itself is covered on 12 ISN reading.