Recently my 24-105mm L lens started showing the "aperture" problem - Err 01 - no communication between lens and body. Most likely because an aperture blade got stuck or the ribbon cable serving the aperture mechanism got dislodged/damaged.
This seems to be a fairly common problem with this lens and requires expensive repairs ($350 - $650).
Although I read quite a few reports here and there about this problem Canon seems to ignore it and pretends it "does not exist". IMHO this must be a design fault or inherent weakness which they should recognise and take resposibility for - especially as this lens has the "L" label for "professional" use.
I would like to make an inventory of all complaints and with this inventory build a case against Canon. Here in Australia I could report the case to the ACCC (Australian Competition and Consumer Commission).
Please report your personal experience in this thread or send me a PM with details.