SPD signal ECU

[ambiorix]

I have a question about the SPD signal for the ECU.

It concerns a 4A-GE 7rib engine ( non TVIS ) built into a kitcar. On the ECU there is a connection for the speed of the car ( not the revs ), which is deliverd by a speedsensor inside the combination meter.
As the kitcar doesn't use the speedo of the Corolla AE92, I don't have this signaal and I get the faultcode is 42 from the ECU.
I also do not use the blue idle-up VSV valve to raise the revs at idle, all vacuum ports on the throttle housing are blocked.

Is it possible to run the kitcar this way, using no SPD signal ? What are the concequences driving the car in this mode ?
Why does the ECU need the speedsignal from the car ?
Does anybody know a way to suply the ECU with a proper signal that it can use ?

The last question is directed at the Westfield and Caterham builders who will encounter the same problem when using a Toyota fuel injected engine.