have been having problems lately with my 2001 Excursion with 7.3 PSD that has 60K miles on her.
I turn the key to start but it will not crank over. All the usual lights come on but the starter will not engage. If I move my gear selector from Neutral back to park a few times - starter engages and the truck starts.
When I plug in my Superchips Tuner to check for error codes it comes out with a P0603 Internal Ctrl Mod KAM error and a P0683 Glow Plug Ctrl Mod to PCM Comm Circuit error.
Becoming a real pain in the ass and seems to be getting worse. Anyone have similar issues? Not sure why moving the gear selector repeatedly fixes the situation if I get the above error codes. Anyone have any ideas?
I would suggest that you look at the actual readings from the inhibitor switch when it's in Park and Neutral. Sounds like you may have high resistance somewhere, could be a connector or internal (switch). If not, check the linkages from your gear selector to the gearbox to see if they're adjusted properly, damaged bushes, etc.