Hello there!!  1st post - thanks in advance for access to such a great site!!

My 2012 just started doing the same thing.  The needle is sitting at 5k with key off, not running. 
Searching for answers/any hints before I tear the thing apart. It had been working fine until I disconnected the battery to add a USB charger.  Any chance it just needs to be re-calibrated??
Thanks guys!!