code p0601 won't go away

I've look and read some different things but when it gets down to it this code just won't go away. I just don't get it. this is a 2002 ram 1500 4.7L automatic now my first codes were P0505 IAC, P0601 Fault memory sum and finally P0121 tps sig. Now i replaced the spark plugs wire's, Plugs, TPS, IAC and still this code remains.:crying: Whats so funny about this is that even when i clear this code it comes right back in twenty mins. after changing everything the truck runs fine but before it kept stalling. now i got this code returning can anyone help????:banghead:

P0601GenericInternal Control Module Memory Check Sum Error
Computer has an internal fault and the only way to get rid of the code is replace the it. PCM is warrantied for 8yrs or 80,000 miles.

Dang. 90k on mine, so i guess i need to replace the pcm??? figure's

replacement was done at dealer thanks for the help
again
jpb53