We change CLC batteries with power on all the time. While it works on most, occasionally you do need to reprogram a unit. Sounds like you have one of those units. We change the batteries annually on DMC units and I normally send one guy around to do all of them. While he ends up with allot of wheel time, it ends up faster than having the individual mechanics play around with resetting the units. Whenever we get a new one on service, we go out and copy the software chips and back up the programs. That way we have all the settings in case of a failure.
