[Boghog]

The powertrain control module (PCM) stores information in keep alive random access memory (RAM), or keep alive memory(KAM ) a memory integrated circuit, about vehicle operating conditions, and then uses this information to compensate for component variability. Keep alive RAM /KAM remains powered when the vehicle ignition key is OFF so that this information is not lost.​

 

[Canuck623]

You are correct in how it works but Ford's acronym for it is KAM not RAM. You will hear me tell people to reset the KAM. That returns all fuel settings to the factory table. Even after a repair is made if you don't reset KAM the fuel tables will continue to operate as if nothing has been fixed until it eventually gets back to normal. Just clearing codes does not clear KAM.

 

[theoldwizard1]

The simplest way to clear all of KAM is to disconnect the negative cable from the battery for at least 15 minutes. The car might run a bit odd for the next couple of trips as the PCM "re-learns" some of its adaptive algorithms.

BTW, in the not too distant future, DTCs will stored in no-volatile RAM. This means that simply unhooking the battery will not erase codes ! New EPA requirement.