That is normal, as the speedo is designed to over read by about six kph at 100 kph, (at least that was the case in the E-series dash).
The trip computer works off the module pulses and computer and is more accurate. It will give a instant speed when reset
The VDO speed alert system works off the same sources as the trip computer.
Believe the trip computer and speed alert as its more accurate but drive off the speedo. It will allow a margin for speed cameras and radars that may just and has probably saved me a few times.
For those people with x police vehicles, be very carfull as the speedo is designed to underread. All these errors are there to ensure when you booked for speeding, your definitely speeding.
Source: retired VDO employee.
Ford Doctor. Who requires a transfusion?