[S4atlast!]

is speed wire necessary or can one program the unit as an A4 and not use the speed signal?

 

[PetrolDave]

is speed wire necessary or can one program the unit as an A4 and not use the speed signal?

Serach the forums to confirm this but AFAIK the 4B0 unit can be coded as an A4 to take the speed signal over CAN - which will be OK provided of course it is on CAN on your allroad.

 

[AudiA4B6US]

craigyb confirmed in his A8 that the 4B0 can be programmed to use either speed over CAN or via the v-pin (see here for details). However, only the A3 8P, A4 B6 and A8 D2 (late models only?) support speed over CAN.