Rush Peterbilt of Fort Worth Tx. told us the ecm could not be reset without password. That sounds pretty far fetched to me , they said my only other opption would be to replace ecm. Which they could redily produce.
Customer parameters can be protected by customer passwords. The customer passwords are programmed by the customer. Factory passwords can be used to change customer passwords if customer passwords are lost.
My advice would be to find a different dealer the above post is straight out of the CAT repair manual.