P2301 - Ignition coil A primary control circuit high

Question

I have a 2005 R52 cooper S which has gone into limp mode with the fault code P2301 'Ignition coil A primary control circuit high'. I have replaced the coil with no change so I changed the ecu & still no change, I've disconnected the coil & I still get the fault when turning the engine over. Any help please as this is starting to cost a fortune & the car is still off the road?