Two Letters Re: Storing Spare Vehicle CPUs for EMP Preparedness
Sir: Most computerized gas engine vehicles built before 1996 (OBD-I) have a permanent computer memory module called a Mem-cal or PROM (programmed read-only memory) which can be stored indefinitely or used as-is from a parts house or junkyard. OBD-II vehicles, generally 1996 and later, all use the writable E-PROM which requires a specialized program and equipment to re-write. Also, the newer the OBD-II vehicle, the more computers it is likely to have. However only the module(s) for the power train are mission-critical. E-PROMs are more delicate than the older PROMs and sometimes require “re-flashing” to restore functionality. Obviously, the older …