Sorry we haven't gotten back to you sooner. I noted that you tried the relearn. Tell me, when you turn the key on for 10 minutes, did the theft light ever turn off? When you put the key in the vehicle, does the "Key Not Accepted" light illuminate on the info display in the vehicle?
All control modules in the Saab 9-5 are connected to the CAN bus with the exception of ABS and SRS. I really feel you should scan the CAN bus system as Ken mentioned to see if there is a break down at the BCM before you replace it.
I attached a pic below showing the bus system on the vehicle. There are only two, P-bus and I-bus. These systems are all tied together with two wires. If there is a break down, it can shut several things down. In this case, the anti theft is engaged.
Try the CAN scan mentioned. Otherwise, it will become a guessing game. Let us know what you find.
Monday, July 20th, 2020 AT 7:24 PM