From V6R2H release notes - Prevent logging 1529 "drive comm loss" faults on TAC32H.

Keep in mind TKE runs the same software in all CPUA processors. So that includes Tac 50/04 32 bit, Tac 32H (includes HMRL), and Tac 32T. So its possible it may be in reference to a traction drive, also I’ve heard speculation that future HMRLs may control hydro pump motor with a drive rather than soft start. Point is you have to realize how much is packaged in current release software.