If you get messages like: "Immobilizer see manual", "anti-skid temporarily off", "anti-skid service required", "srs airbag service urgent", instrument cluster goes mad, or you have no control over central locks, wipers, climate...
Most likely you can fix those issues by removing rust and dirt from CEM connectors.

3 months later
Time for me to do this.
I have message disco central when tugging on the wheel hard
Let us know how this goes

Im amazed i dont have the issues on my car considering the water ingress i have on it
so I pulled all the plugs and removed the CEM (and it's bracket, so I could change the cabin filter at the same time) and nothing looked loose or damaged. I cleaned all the contacts with CRC contact cleaner and re installed. I've just come upstairs to wash up, i'll take the volvo out on some errands and report back.