Zanussi washing machine is not working & is displaying error code E91

My old Zanussi error code book doesn't even list an E91 error. However, when an error code says communication error there's little you can do. There is a display PCB and a main PCB with wires and connectors between them. For some reason the two PCBs can't communicate with each other. So, it could be a fault on the control panel PCB, a fault on the main PCB, a fault on both, or a connection fault on the wires and block connectors that go between them. Just ordering and replacing either of the PCBs is asking for trouble and pure guesswork that could easily end up wasting a lot of money.

Even a Zanussi engineer is unlikely to be able to work out what it is. They would be most likely to just order both boards if it was under any sort of warranty or cover. They would then fit the easiest PCB to replace and if it fixed it sweet. If not, they would fit the other and then panic if that didn't work either. A good engineer might inspect the connecting wires and connectors first. If the machine was not under any warranty they would as likely as not just say it isn't worth repairing.