I think your ECU have output for RPM, even there is no wire in original instalation. At least that is case with ME 7.5
VSS must go to cluster, then cluster convert VSS to digital signal (12V) that goes to ECU. I doesn't know does MK2 cluster have speed output(blue/white wire)
But you can build some simple electronic ciruit to build that converter VSS to 12 V
Thanks for your answer. that ecu is CAN bus ecu, and that ECU can't see analogue speed signal and not recive RPM signal on output. Only CAN. I need analogue RPM signal for my rev counter.
For a tests I changed GGVFZG in software from 02 to 00, then ECU see speed from analogue input.
The question is if I change GGVFZG then RPM signal output will be active too?