Hi guys,

I have a E70 that i have a replacement DDE that needs matching on the bench.
The ISN matching from replacement DDE into the CAS is easy.
My question is, how do i match the EGS?
The replacement DME is the older type with only a 4 digit ISN. So for example, if the CAS ISN is : 1F 85 6C 15, the last four digits are for the DDE, which is 6C 15. When i change the CAS ISN and input the new DDE ISN which is D6D5 for example, the new ISN becomes 1F 85 D6 D5, after this, will the EGS be matched?

Thanks guys

You are making mistake here. In your example 1F 85 is the EGS ISN and 6C 15 is the DDE ISN. 4 digits is incorrect. It is 2 bytes or 16 bits.
Anyway, what you want to do is not going to work. The only way I see is to find an old CAS that is using 2 byte ISN, sync it with the DDE and then sync the EGS.