I have a customer that has an ECU he wants to swap in to his car (X5 diesel). It is already tuned. If I use autohex and sync CAS it typically reflashes the ecu, so would overwrite whatever is there. Do I have another way of doing this move in autohex or hextag?

Or read in hextag the P and D flash, then sync with autohex, then flash back the P and D flash?

Thanks

Is this an E70 X5D with EDC17CP09? You should be able to read ISN in factory mode, then simply write DDE ISN into CAS module. But you would still need to match up injector codes, etc. Edit: If this is e70, changing CAS ISN might not be possible because of EGS ISN.
It would be much cleaner to clone his existing DDE and have it tuned. That allows 2 working DDE and avoids changing up vehicle ISN.

hi,
if your original dde already tuned and you want to keep that tuning then its better to clone the dde with hextag. just make backup of both dde in hextag and restore original dde backup to used dde. all data will be transferred to used dde including tuning this way. if you use autohex it can match isn with used dde and cas but tuned files cannot be transferred to used dde. for hextag cloning you need active cloning license please check here for more info
https://www.microtronik....hextag-programmer-hp0001 

Extra difficulty now.
I have full autohex and hexprog here.
They are not local and want to ship only the ECUs to me.

Full clone seems like the best approach, but then I have no way to move ISN back in to this ECU? Or no way to move new ISN to CAS in the car.

Extra difficulty now.
I have full autohex and hexprog here.
They are not local and want to ship only the ECUs to me.

Full clone seems like the best approach, but then I have no way to move ISN back in to this ECU? Or no way to move new ISN to CAS in the car.

if you clone original ecu to used all info including vin isn and tuning will be transferred. so no need to match isn again on cas and donor dde after cloning. its just plug and play. get original and donor ecu shipped to clone with hextag. make sure you have valid cloning license in hextag to clone ecus and clone ecus on bench, make backup of both ecus first and restore original ecu backup to donor.