4lo illuminates at freeway speed

[Hi-desertT4R]

I’ve been having this intermittent issue for about two years now and after many searches here on the forum and FB groups I still haven’t determined the cause of the 4lo light coming on when driving on the highway. 2007 SR5 4WD V6. It usually happens when climbing a grade or when downshifting to pass and resets once the truck is turned off or if I cycle it into 4hi and back to 2hi. No other lights come on in conjunction with this and no codes are shown when I connect my scan tool. Even more rare than this is the abs/vsc/trac off which once in a while includes but not always the CEL. Those codes are C0256 & C1223.

I’m thinking I have a shift solenoid problem but I figure I’d have a code for a specific transmission issue but I’m just a backyard mechanic, what the heck do I know?

Anyone else have the 4lo light come on while driving on the highway? It’s very strange but it doesn’t effect drivability so I just let it go but I’d like to fix the cause before it leads to a bigger issue.
Thanks

 

[Cezar]

That is weird as hell.

BTW if you drop your steering wheel adjustment it opens up a nook and that scangauge slots in perfectly.