5 out of 6 glow plus were faulty as well as the glow plug control module in my WH & it didn't bring the engine light on.
A suspect 02 sensor so far is the only cause of the check engine light I have had so far.
Get the 4.7k resister, unplug the swirl motor, put the resistor across the centre 2 pins and see if it is back to normal, this will tell you if it is/isn't the swirl motor.
It really is simple.
http://www.wranglerforum.com/f19/gra...rd-181047.html
Then you can decide if you want the stealership to do the repair.