After I got dun fueling today. I went to restart my truck and imediatly the RPM's jumped up to 1500-1600 for 1-2 seconds then dropped back to normal. I noticed the CEL light was on so I retrieved the codes using the "key" trucks. I got 1693, and 1698 ( No CCD Messages REcieved from PCM) Anyone know what that means???? The truck seems to be running fine, other than that one incident of elevated RPMS. Any help is much appreciated!!

 

sounds like it trapped a communications fault. If you have the ability to clear the code, try that and see if it comes back. the 1693 is a companion code, so it will appear with another code (in this case its 1698), which my understanding is the TCM (transmission control module J1850 communication fault). I'm not positive, but I think it gives the tach and speedometer readings from the TCM, so that would make sense.

Try clearing it if you can and see if you get it again.