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 style would be preferable in a grid-down situation. – Dave B. in Texas
Greetings JWR:
Thanks for all your hard work on SurvivalBlog, I look forward to reading it every day.
This is regarding Jim S. in Ohio’s letter on EMP prepping his 2006 F250 Diesel. There are multiple modules on the vehicle that would need to be purchased, “flashed” and stored for EMP “Disaster Recovery”, just to make the vehicle run. Many of these modules are vehicle specific due to calibrations, and would need to be “flashed” by the dealer at an additional expense. To do this properly, one would work closely with their Ford Service Center to procure the proper parts and arrange to have them installed and flashed. Once tested and verified, you could reinstall the originals or keep the new working pieces and store the originals in EMP protective cases/containers with the tools needed to replace them. The saving grace in Jim’s case is the F250 Diesels did not have the Passive Anti-Theft System (PATS) keys, I believe that started in 2008 for the F250.
This would require additional key programming and another “interrogator” as it is nothing more than an antenna, and possibly subject to EMP itself. You can find the interrogator coil in a plastic “halo” surrounding the shroud on the ignition switch. Ford vehicles use different models of PATS over the years, each is specific to the vehicle model and year. Each key has a specific code (128 bit or 3.402823669209e+38), which must be programmed in to the Powertrain Control Module (PCM) by the user, or dealer – depending on the version. Without the proper key type and code, there is no fuel or spark initiated at start up – it just cranks.
My recommendation for PATS type vehicles is to use the two factory keys to prepare three additional keys. Keys 1 and 2 are the factory keys and get locked in a safe – do not use them. Key 3 is used as your “daily use” key. Key 4 is your “EMP Event” key – treat it accordingly and store it hidden, inside the vehicle. Key 5 is a non-PATS key, cut twith teh intent of opening the doors, unlocking the steering and running accessories. It is stored where accessible (home, work, wallet).
If and when the 3rd key gets lost or destroyed, the 5th key (or a rock) is used to gain access to the vehicle and the 4th key is used to get you home. Later, keys 1 and 2 are used to add an additional key.
Notice “add“, since not all vehicles let you remove keys. This is a potential security issue as the person with that key could still operate your vehicle, just not to make new keys.
Should our region be hit with EMP, I have a flash programmer that can be used to install a custom tune which removes PATS, all limiters/codes and allows me to run on substandard/alternative fuels. This is my cost effective alternative to purchasing a specific, EMP resistant vehicle. This will work for file corruption, but not for a total PCM failure. Thanks, – Fred in Washington