after searching came across your post and I think I already know the answer but at the outrageous cost of replacing D.O. I'm trying to exhaust all other options 1st.

Theres not alot of info out there on these DO as it comes "pre-configured" per job specs. I also have same issue on one now.
I have used the SSM and all parameters appear to still be correct
SSM is giving me fault code "5" which I do not know what it is?

1) "running in slow speed" is synchronization speed
2) put elev on cartop insp. and.do "hard reset" hold down open and close buttons at same time, all 5 leds should flash on and off after doors do learn run "ERR" led should be off.
3) my problem is I can not get doors to do learn run and "ERR" led stays lit.

Thanks