My washing machine won't finnish cycle ?

Hi my washing machine is a hoover new wave plus 5 auto-washer 1500 electronic. It won't finnish cycle. It stops when it is trying to rinse and spin leaving machine with soapy water in. It shows error 1 on display and all red led lights flashing. If I turn machine off and restart on quick wash it will complete. sometimes I have to do this again to get machine to finnish.occasionally it will complete a full wash cycle.I have looked at another post on here and wander if same principles apply about checking sump for debri etc.Have no manual for machine.Can someone help please?