Creator 310 gets communication error when trying to scan BCM. All other modules read OK. Does this automatically mean I need to replace BCM? Only BCM symptom is rear trunk switch doesn't work (see this thread). Zero evidence of water near BCM. September 04 build.

 

It could be the scan tool itself and not your car. I had a similar issue with my D-CAN cable running ISTA. New cable solved the problem.