I'm having the same, intermittent issue on my '07 Classic, but no trouble codes. Usually, moving the shifter to park and then back in gear (either forward or reverse, does it on both) clears the issue. However, blackpearllmm said something that interested me: I sometimes get the security light on the dash when locking the truck. Now, I have an aftermarket alarm/remote start system, but the Range Inhibited issue was occurring before the system was installed. The alarm system sometimes gives me fits (horn will sound a confirmation when it feels like it, or not), delayed locking or unlocking, and other gremlins.
Could this be tied to a faulty ignition switch/voltage issue, as well? My alarm installer is absolutely befuddled by the issues, as it's a system that's known to be pretty reliable...
2007 GMC Sierra Classic SLT K3500 CC DRW.
19.5" Alcoas with 245/70R19.5 Goodyear treads, AFE 5" exhaust, Edge Attitude CTS, AMP Powersteps, Bilstein 5100's