Multitronic problem switching from D to S

[Family Wagon]

Hi

I have a Audi A4 1.9tdi 130 sport with the multitronic box its a great car but recently it has developed a fault that when driving in D mode the car switches itself into S mode.

I have had the car scanned with a bosch diagnostic tool and has given the fault code p0706 Driving postion Sensor signal improbable.

I have searched through the forums and it looks like it could be the gearbox ECU which is an expensive part to replace. I've just been made redundant and don't have the cash to fix it at the moment.

Will this cause serious damage to the gearbox?

Thanks