I have a 2002 2500 diesel with an auto. During a recent cycle of the key to do a code check I pulled up this code: P1694.
According to the book, this means: No BUS MSG received from ECMMOD. Could someone tell me what that means in laymens terms? Not sure if its an old code or not, is there a way to clear the codes without a special tool?

 

check all 500 million grounds, mine has done some strange issues, and i was amazed at what a bad ground will do