Has anyone tried a Healtech SpeedoHealer? Basically it intersects the signal between the wheel sensor and speedo to enable calibration. Bikers use it when fitting different size wheels etc.
Assuming we are in agreement with Keith's (burgundymog) findings, it would seem the ECU forwards the accurate wheel pulses to the VDO speedo head. Its their internal computation into an analogue speed display that seems to be at error therefore not the computation into digital odometer display and trip.
Not sure if your solution would correct one without the other.
