Volvo fh500 2016 8 wheeler with rear steer

Right my truck has gone into workshop for looking at tomorrow as when driving it a few warnings came up on the dash and tacho, ims fault 81 on taco and clutch malfunction, truck brake malfunction and rear steer malfunction, all came on together so guessing faulty wiring or control unit, the auto gearbox won’t work as I believe ims fault 81 is a signal fault so took it to workshop in manual and rear steer doesn’t turn, just wondering if anyone has had the same… :question: