2002 CL erratic speedometer

[Cobra]

Hi guys

My wife's 2002 LR Focus CL 1.8L has been suffering from an erratic speedometer issue for about 6 months now. It started sporadically dropping to zero and would only start working again once the engine was turned off and switched back on again.

It had been occurring more and more frequently until the last week or so when it stuck at 60km and hasn't returned to its normal state regardless of turning the engine off and on again. There are no other uccompanying symptoms like running rough, stalling etc. Just speedo not working and that's it.

I have a few ideas on where to start looking, but I don't see the point in reinventing the wheel if someone else has already discovered and uncovered these exact symptoms. I'll start with checking the battery voltage and charging rate, as well as checking the wires for the VSS around the gearbox.

Providing they're all fine, I'm guessing the VSS may have an issue itself. But I'd rather not go replacing it willy-nilly. If all things lead to the VSS being the issue, or if this problem is very common with VSS being the culprit almost every time, then I replace it.

Any help/feedback with this issue will be greatly appreciated.