Take the top off the control box at the side of the battery. You need to pull out the Relay board (5 relays on it) which are not visible yet, this board is the nearest one to the engine.(it's quite awkward to pull out, there is quite a bit of jiggling and moving cables out of the way but the end result is worthwhile). You need a small soldering iron, resinflux cored solder, a decent magnifying glass. Look at the printed side of the board, at the top near the plastic plug holder, look very closely at pin connectors coming thro' from other side for hairline cracks round the pins(specially the corner ones) and resolder these joints, if in doubt do them all. To make it a little easier , if you unplug the board , it will not upset the computer. Put it all back together and MAGIC it works, fault found and gone forever. Happy days and good luck.