I had the same issue, turned out to be the wiring harness going to the canshaft position sensor. This is a common problem according to the mechanic that installed mine at Jeep. The part is $43, labor $375. $508 after it was all said and done.
$375 to replace the harness??? I think my CPS sensor is bad too so I checked it out to see how the harness runs in case I have to replace it as well. I believe it just runs straight to the back of the starter. If so, it would take, at most, 30 minutes to replace.