u/Ecstatic_Peace_6323

I’ve got an 03 6.6 duramax. It will not shut down by the key and it’s throwing a fuel rail pressure sensor. I’m shutting it down by a main relay and the fuel pump will still run so I pull the fuel pump relay as well. It’s got a FASS fuel pump system installed by previous owner. It’s not the ignition itself, it’s been replaced. I’ve also tried replacing the fuel pump relay on the fire wall and that’s not it either. Anyone have any ideas?