Speedo P1555ing me off!!

[P1555ED]

Changed speed sensor, changed speed convertor, changed speedo, £280 later, still doesn't work, only intermittently for seconds at a time. When it is working it even works in reverse!!

Is there any way I can check there is a constant signal coming from speed sensor to the connection at the back of the dash?

 

[oldaneal]

think that the speedo sensor can be checked with a meter as it is effectively just a ground and it wil just alternate between ground and no conection as the car is moving but will check mine

 

[P1555ED]

Still confused, could I use a volt meter and connect it to the KMH output and earth?

And then drive it and see if I get a current?