This relates to the BST, or Battery Safety Terminal. There is a pyro-technic charge built in to the positive cable that connects to the battery. In the event of an accident the airbag module sends a signal to the BST & the charge explodes cutting the power to the car (the cable breaks with the mini explosion).
"Resistance too high" probably means the little black cable on the BST is disconnected, you will see a black/yellow connector on this.

When you power on the car the airbag module "checks" all the satellite devices (e.g. Airbags, crash sensors, seat mat, seals belt tensioners & BST). It does this by measuring the resistance in ohms of each of the devices, if it comes back greater than 6ohms from any of these circuits then it will trigger a fault as being present & illuminate the airbag light in the instrument cluster.
If it is to low it will also trigger an airbag light, eg if someone used a plain piece of wire to bypass the airbag or sensor.
There also could be a problem with the software version on the repaired module. I hit this issue on a car a few years ago.