Well, one of the things I have learned is that a lot of the time the fault codes don't really help that much. It's possible you had a momentary power drop out which can generate almost any fault code. Sort of like playing Wheel of Fortune. I recently have had to go troubleshoot plc faults at 2 customer locations. The first location had a ML1000 and the fault was "unexpected result at end of scan". Now how helpful is that? It ended up being a hardware failure. The second location had a 5/05 and the fault code there was something about a watchdog error. The customer said they had a storm the day before with a nearby lighting strike. I cleared the fault and it's been running about 2 weeks now with no issues. Again, my theory was a power surge or, more likely, a power cycle or multiple power cycles in a short time. None of this may be of help to you but I thought I would pass it on.