to be honest it could be anything causing it, just changing parts with out knowing what wrong will cost you a load of money.
The only advice i can give you is if you or a family member are a member of the AA, RAC or similar give them a ring get them to come out, tell them your eml light is on and is in limp mod
and is un usable, they will come round plug in there daig machine and pull off the code or codes.
then we have a good starting point if its something they carry they might be able to sort it then and there may be.
if not get the codes and some one here will be able to help out :-)
sometimes you have to clear the EML light to clear the fault it does not always go depending on what the fault is.
you could disconnect the batter and leave it of 10- 15 min then see if has cleared but it may come straight back on if you start or drive it
sorry i could not be more helpfull