Toxic warning light - code p0010

[Mav]

Recently had all 4 coils replaced at main dealer, three weeks later toxic light back on but solid, car running ok. had a friend of a friend with a diagnostic machine plug it in today and fault code p0010 came up with discription 'camshaft position actuator A bank 1 circuit malfunction.' anyone know what that means in laymans terms? is it big job or just a dirty sensor? any comments welcome.