You can run the car off of the mlb board by removing the communication cable going into the ocss board . All commands would have to be given from the service tool at that point and it would have to be plugged into the mlb board .commands would be given in M-2-1-2 menu. You can also force the car hall cutout switch on in the M-1-3-2 menu parameter 2489 I believe. You’d still be able to run the car from your ocss board and it won’t answer hall calls just car calls . It would still respond do group functions like fire recall, etc.