S90 faulty window regulator

Considering the symptoms and the stored error, a defective power window switch is certainly plausible. Have you inspected the switch for visible damage or performed any initial electrical testing on the circuit?

I haven't performed any electrical testing yet, but I will look at the schematics. Any guidance on interpreting the error code itself?

Interpreting the specific error code would be beneficial. Considering the age and mileage, and absent any obvious wiring faults, replacement of the switch module may be a prudent first step, but without diagnostics it is impossible to be definitive. Perhaps a workshop visit is warranted to rule out other issues.

Thanks. The issue was indeed the power window switch. Replacement cost was 200€.