Lavamat error c3

My AEG OKO LAVAMAT Update 84749 is showing error C3. When I switched it off, the pump sounded as though it was still running, until I switched off electricity at the plug. When I turned plug switch back on (but machine still off) the pump started again apparently of its own accord. Apparently C3 means: “Safety flood device operated, pump fault, module fault.” It hasn’t flooded. So, please can someone tell me: do I need an new pump, if so, how do I find which one I need, and is that even possible on this relatively old machine. ? Thanks!