I just came out of a similar situation with my 4200. Had to get the whole speedo replaced. But it could be anything
Check the 3 multi plugs where they plug into the canbus box above the accelerator pedal. Give them a spray up with contact cleaner. The speedo is electrical pulse driven from the ABS sensors.
The whole speedo?
Thanks Matt, I'll give that a go
Sorry meant whole cluster. My speedo was sticking though. So if I was accelerating to 60, it would read as 20 then suddenly jump to 60 and same when decelerating. Never showed the true speed.