I have been using CarPlay for awhile now (IPhone 6, iOS8.1.3) on the NEX 4000 and all worked pretty well.  Suddenly I am having lots of problems getting anything to work, such as,

• Click on Maps, Maps Loads, click on search, no Siri and if I speak "Take me home" nothing happens.  However, if I manually type in a location into the phone and then hit start, it will navigate and display the maps.
• Click on Messages, or a received message that does show, CarPlay appears to read it, but you do not hear anything, and it will not reply
• Click on Phone, and it does not ask you who to call.  If you manually enter someone, it does not play thorgh speakewrs but calls, and you need to go through phone manually by unplugging etc
• Click on Music, sometimes works, but sometimes plays but you do not hear.  Then I either disconnect and reconnect, or toggle between iphone mode vs pioneer mode vs auto receiver mode and theat seems to fix it.

Nothing new to the phone or unit that I can think of.  I have reset the phone and the NEX Unit.  Neither worked.    Siri works fine when phone disconnected.  My next steop is to restore the phone but wanted to see if others have experienced the same problem.

When you say that you reset the phone. What does that mean exactly?

Did you press and hold the Sleep/Wake and Home button until the iPhone resets? This process takes about 45 seconds. You'll have to hold those two buttons together until the Apple logo appears.

KOT

Yes, that is exactly what I did, multiple times.

I noticed a couple odd things with my CarPlay setup as well. I was getting a lot of disconnects and some random radio reboots. Finally I noticed that the Lightning cable would come out of the iPhone very easily. At first, I thought that my everyday use of plugging in the cable into my phone about a dozen times cause the iPhone connector to loosen up. Then it hit me. I carry the iPhone in my pocket most of the time. So, I looked inside the iPhone Lightning socket and saw a bunch of lint. A LOT of lint. After removing all that junk, the cable was tight again and I have not had any disconnect or reboot issues.

We spend our time looking for complicated solutions to simple problems...

Appreciate the comment, that did not work.  I am going with the "Reset All Settings" which usually fixes or improves the issue, but we shall see.  I will report back when  I have a chance.

I know it sounds wonky but try a new lightning cable

Thanks, I thought it might be the ligtning cable becasue I had purchsed a special audio cable that was apple certified but when I switched it out, the problems persisted.  Then, I tried other iPhones and they worked so I knew it was my phone causing the issues.

So I did a settings reset on the iPhone  and that did not work either.  Finally, I did a full restore on the iPhone, and It worked, and fixed all the CarPlay issues.

Done.

Spoke too soon, after working thorugh a cycle and one connection, itdoesn't work again, very discouraging.  My only thought is that I dropped my phone in the snow about two weeks ago and it was wet for about a minute.  Perhaps this is a hardware problem.

Exactly same thing is happening with my Nex-6000.

Carplay worked for couple of days and than quit again, so frustrating.

...semi good news...  I found a setting in the phone, Restrictions, then unset CarPlay, and connected.  Then I unconnected, reset the phone, and turned Carplay back on, and for awhile everything worked great.  I turned the car off, unplugged, connected again and new problems emerged.  Now you Siri but nothing happens with the commands.

thus the saga continues...

Did CarPlay work, then stopped? Did you have work done where the battery was disconnected? This happened to me and Carplay stopped working. My installer clued me in on what to do (you won't find this in the manual):

With the open end of a paper clip, poke the pin-hole button on the far right end of the bottom button row. The pin-hole button is almost invisible - hard to spot. When you poke it with the paper clip end, the screen will go blank for a second or two, then come back on (this is like a 'control-alt-delete' on a computer). You will have to redo some of the setup and presets, but CarPlay should now work.

You're welcome.

Thank you for the effort, but what you have described is the reset function of the NEX Unit.    I have done that several times, in fact, I do that once every 6 months or so because it seems to help the unit function better because it does reset everything and is like rebooting the phone or PC.   However, it did not fix my issues with CarPlay the two times I tried it.

It could be the lightning cable causing issues, I use the syncewire from amazon that has a lifetime warranty and replacement with no questions asked. very good price and works better than the original. I've had three original wires fail already. 

Interesting, when the wires failed, what happened?

_{I want to thank Edwin and several others on this thread who suggested changing the lighting cable.  This simple fix appears to have solved my problems.  I had bought a special lightning cable that was for increased speed and audio and was dubbed apple certified but does seem to be the cause of my problems.  I had tried a different lightning cable earlier and it didn't work I think because I did not restart car and reset everything.  This time when I reset everything, Carplay is working all the time now.  Hope it holds, and what a relief!}