The TBGM2 is 1 time programming. It cannot be reprogrammed. Another TB-GM2 would be needed and reprogrammed (not the entire remote start system). Only reason the TBGM2 would need to be changed is if new keys were ever added to the car or if the BCM or any other major component in the car had to be replaced or reprogrammed previously.
Another thing to check is the antenna ring itself. It needs to be tested for continuity ensuring the wire or ring is not cracked.
It also important to test that the remote starter is activating the TBGM2 upon remote start.
There could be other reason, this is dependant on the installation type...
Product info: https://fortin.ca/en/products/transponders_(tb)/tb-gm2/
There could be other reason, this is dependant on the installation type...