Could be either one of the control boxes or the light units themselves giving the error - unfortunately no other way than to take it to VX - if it's the light unit, they're ?700 each!!
I had this when I first got mine, and it ended up being replaced by the dealer at their cost (after much fighting!!)
I had this when I first got mine, and it ended up being replaced by the dealer at their cost (after much fighting!!)