Nexus 4 won't turn Bluetooth on
Seem to be an Android bug. I found this in the Android bug tracker.

https://code.google.com/p/android/issues/detail?id=42520&amp;q=summary%3Abluetooth%20type%3Adefect&amp;sort=-stars&amp;colspec=ID%20Type%20Status%20Owner%20Summary%20Stars