The code can be on DSC, VTG or LWS module.
It doesn't stop to amaze that there can be problems with freezing washer fluid. Here in Finland we (or at least I do) use the same stuff all year round which can cope down to -30 C. This has also better washing properties on insects during summer time. Previously I had a contact at BMW Germany for parts supply. Sometimes he sent with the parts package original BMW washer fluid tablets as a free gift. I had to use search what I'm supposed to do with them.