The OP needs to figure out what is the code first. This can be done with any of the code readers or scanners. Then go from there. It is most likely that is the SRS system code , because he disconnected the bumper connector, which is most likely a collision sensor, while the battery was still on...
The light was triggered most likely by not forgetting to plug the connector back in, but because the connector was disconnected while the battery was still connected, it should be disconnected before doing this kind of work. Usually the high level scanners are able to reset these kind of codes...