Speedometer not giving exact speed or not at all

[AlexPagal]

Hi,

My speedometer has started behaving strangely, right after my car battery went dead (was away for a while) and the breakdown guys fitted a new one.

After the new battery was installed, the speed needle didn't move at all. After a while it started moving but it's showing about 5miles/hour more than the electronic reading. This is intermittent, sometimes it won't work at all, sometimes it will show +5m. But it's never right.

I am attaching 2 images (sorry for the quality) to show what I am trying to say.
It's just the needle that won't work, the electronic reading seems fine (checked it versus a gps)

My car is a 52 reg, W211 E220 CDI Auto.

The only solution I could find on this forum was to disconnect my batter and hope for a reboot, but would anyone advise against that?
Any other suggestions?

Thanks,
--Alex

 

[television]

In these very odd fault cases it never does any harm to power down and try again. If the fault persist then the cluster will have to go away for a rebuild.

The correct speed signal is getting the the cluster, its all CAN driven