I used the key on/off method and initially found it to be a bit tricky to get it right. The trick is not to actually turn it back too far to the "LOCK" position but just between the "ON/RUN" and "OFF" position. I can do it consistently with this method......initially turn to "ON/RUN" and back to "OFF", the "OFF" is my first count and I do it twice more ending with a half count being the "ON/RUN" position.
ON/RUN - OFF (one)
ON/RUN - OFF (two)
ON/RUN - OFF (three)
ON/RUN (display will show codes if any or "DONE" if none)
Thanks for the link to the OBDII codes, it is the most comprehensive list I've seen thus far......
Now, I wonder how or why I'm getting the P2509 fault "ECM/PCM Power Input Signal Intermittent"......especially since I've not noticed any issues with the truck at all......