I had a similar problem with my volvo.
It had a ECU controlled alternator, and it had been replaced with a slightly different alternator at some point prior to my ownership.
Apparently it would overcharge and the car would shut off the alternator. So every now and then, the car would light up like a Christmas tree and be bricked, with the wipers running on full hah. (My only car ive ever used AA+ on, twice!)
All modules would throw a code, and it was to do with canbus connection being dropped.
The guy i sold the car to found this out (i sold it bricked as i had no idea what was causing it). Fitted the correct alternator and it was all hunkey dory.