Piaggio Porter Electric


I hope someone can give me a little assistance.

I own a Piaggio Porter Electric van… - As I drive there is an occasional knocking sound (it sounds like it is coming from towards the rear of the vehicle) - at the same time as the sound happens my speedo and rev readout jump up quite high then drop back down again…

The knocking sound is happening approx every 10secs however it is not a rhythmical knocking… it seem to be louder at higher speeds.

also, yesterday when I tried to switch on the vehicle it was reading 0v and would not start (although the 4 green charge lights were illuminated)… but without doing anything a few minutes later it worked again.

I am wondering if there is a sensor or cable that has come lose somewhere and is flapping around while I’m driving and giving dodgy readings.

I have looked under the vehicle and can’t see anything obvious.

I could really use some advice of where to start looking… or a diagram of the the system…

Thanks for your assistance