Dear Rob,

Alarm #12 is for EEPROM Config KO.
Each time that you replace or re-install the steering sensor or the chopper (Motor Driver). You have to connect to the drive by console and adjust the steering sensor for it. For Bi-Motor fork lifts, some times it could become damage driver of one side if the steering sensor is not adjusted correctly.
I do not know if you have solved your problem or not. But I think the best solution could be done by having a programming console and check and adjusting every thing step by step. Let me know if you need more info or details.

Best Regards,