The 'Tarmac' mode cannot be switched, the switch is unresponsive. I have AWD/no problem/no dreaded CEL either...

So... bad switch ahm a thinkin'... Any other ideas?

Unless it is a cheap/easy fix - i may not care...

 

unhook switch from back and try again, or try in another location, either side of steering wheel or under center console phone holder

 

You can always check for continuity on the switch to see if its really broken.

 

This.