PCM error code PO603 "Help!"
 

97' f250 powerstroke, 125K miles. Just purchased and had to change the mechanical fuel pump. Bought an Edge Evolution and read the codes before I set her for the tow package when I came up w/ the following code and description:

PO603 PCM Processor
Keep alive memory
(KAM) Error

Anyone know what this is telling me??

Nothing to worry about. Most chipped trucks bet this error code. Just means that the batteries may have been disconected or the PCM lost battery power for a while.