I factory reset the motion sensor, put it in pairing mode and put it a few inches from the PLM (2412s) . Try to re add it
Wed 12/24/2014 05:10:26 PM : [31 B1 8F ] Added to list of devices to link to ISY Wed 12/24/2014 05:10:26 PM : [iNST-TX-I1 ] 02 62 31 B1 8F 0F 0D 00 Wed 12/24/2014 05:10:26 PM : [iNST-ACK ] 02 62 31.B1.8F 0F 0D 00 06 (00) Wed 12/24/2014 05:10:35 PM : [iNST-TX-I1 ] 02 62 31 B1 8F 0F 0D 00 Wed 12/24/2014 05:10:35 PM : [iNST-ACK ] 02 62 31.B1.8F 0F 0D 00 06 (00) Wed 12/24/2014 05:10:44 PM : [iNST-TX-I1 ] 02 62 31 B1 8F 0F 0D 00 Wed 12/24/2014 05:10:44 PM : [iNST-ACK ] 02 62 31.B1.8F 0F 0D 00 06 (00) Wed 12/24/2014 05:10:48 PM : [31 B1 8F 0 ] Failed to add device Wed 12/24/2014 05:12:09 PM : [iNST-TX-I1 ] 02 62 1D B1 E6 0F 11 FF Wed 12/24/2014 05:12:09 PM : [iNST-ACK ] 02 62 1D.B1.E6 0F 11 FF 06 LTONRR (FF) Wed 12/24/2014 05:12:09 PM : [iNST-SRX ] 02 50 1D.B1.E6 0F.42.41 27 11 FF LTONRR (FF) Wed 12/24/2014 05:12:09 PM : [std-Direct Ack] 1D.B1.E6-->ISY/PLM Group=0, Max Hops=3, Hops Left=1