Airbag Light staying on

[chrisu91]

Over the summer my airbag light would sometimes come on while driving and never stayed on for more than 30 seconds, until last week. The light had been on solid for over 4 days when I finally got to a mechanic. The codes are as follows:

B1104 - passenger seat occupant classification system voltage out of range
B1102 - battery voltage low
B2501 - unknown
B2502 - passenger airbag disabled indicator circuit malfunction

My mechanic suggested my battery might've gone low or dead recently, but my ECM is reporting 13-14 volts when the vehicle is on. Googling hasn't returned too many results unfortunately. They reset the codes and did a test drive and the light stayed off, but the intermittent illumination during the last few months makes me believe there's more to it. Anyone have any experience with this? Vehicle is an 07 Wave.