The ECU powers up, but I cannot connect diagnostics, can you help?

If your ECU is powering up but you are unable to establish a diagnostic connection, this is often due to incompatibility between the ECU and the diagnostic equipment you are using.

Older DDE 4 ECUs use K-line communication for diagnostics, and many modern scanners do not support this. We recommend using BMW INPA software with a K+DCAN cable, which is what we use ourselves.

The earlier E60 (pre-LCI) ECUs can be particularly difficult to communicate with, which is one of the reasons we generally avoid using these ECUs for conversions.

Newer DDE 6 ECUs tend to be easier to work with and are compatible with a wider range of diagnostic equipment. However, it is important to ensure your CAN-bus wiring and termination resistance are correct, as faults here can also prevent communication.