If you have no transpomder chip with the new immobiliser ecu and engine ecu then you'll need to apply for the car pass by plugging in both new ecu's and reading out the chassis number stored. Hopefully they should match.

With this info apply for pass, buy another chip and code in key.

The other way is to apply for car pass for replacement ecu (as before) then depending on your equipment reset new ecu once fitted with the code supplied.

Then with the cars original (car with fault) security code select immobiliser, security code & enter code (original), programming functions, engine ecu installed.


This way will keep the existing key programmed and the cars correct security code in function for future diagnostic/coding work. If its successful you can alter the chassis number in the engine ecu to match the cars vin.



This is all depending on what equipment you have but this is mostly based on my experience with vaux-com so may vary.