Q: Carplay slow to respond on iOS10

I have the same issue but have more information that may help someone diagnose.

The symptoms:

• iOS 10.0.2 on iPhone 6 64 GB
• Pioneer SPH-DA120 Carplay compatible head unit (aftermarket unit I put in my car)
• Timer/counter on music tracks lags anything between 5 and 20 seconds when starting a track
• Works fine on iOS9.3.5 (I actually restored phone back to iOS9 because of this issue and have been using it like that for the last few weeks, stupidly I thought it might now not be an issue in iOS 10 so upgraded again and the issue reappears :-(
• If 'next track' selected during the timer lag, next track won't play until lag is passed and then the future lag seems to accumulate

Troubleshooting info:

• Now I also have a brand new iPhone SE 64 GB (for work). This is running iOS 10.0.2 and never lags on the same Carplay unit.
• So same iOS on two different iPhones (6 and SE) but Carplay issue only evident on the iPhone 6.
• Once the iPhone 6 is connected to Carplay and demonstrates the lag issue, the issue is also present in Music on the phone once disconnected from the car.
• Quitting the Music app (double click on home button and drag up) makes the relaunched Music app responsive until it is next connected to the car.

Anyone got any idea other than going back to iOS9 again (a major pain to do as have to re-download all the music and reactivate cards in wallet, online banking etc)??

One thought is that there are approx 3500 songs on the iPhone 6 and only about 800 on the SE. I'm going to download more to the SE to see if the issue appears. Otherwise I can only think that my 14 month old £600 iPhone 6 64GB is not powerful enough to run Carplay on iOS 10.

Done more testing and found out more about what causes the problem...

• It really only happens if the phone has a large number of downloaded songs and you try to get Carplay to play all downloaded songs on shuffle (I confirmed this by downloading circa 4000 songs onto my new iPhone SE and the same problem as my iPhone 6 resulted).
• If you put a large amount of songs into a playlist and then play that playlist via Carplay on shuffle the problem doesn't occur.

So that's the workaround I'm going to do until Apple will presumably fix this in a future iOS update.

Hi GSer,

thanks for sharing this. I have an IPhone 6s with 128GB on a Pioneer SPH-DA120 and I am experiencing the same problem. Your post confirms my suspicion that the large playlist is causing the problem.

@Apple: Please fix this :-)

Hi his0001 and Jenf1979,

I've found that putting the same number of songs into a playlist works around the issue (i.e. it doesn't need to be a 'smaller' playlist, with any playlist there is no delay). It is only when directly shuffling all downloaded songs (i.e. not in a playlist) that the problem shows. So putting all you music into a playlist appears to be a workaround until Apple fix it.

Hi GSer,

I'd love to confirm that but can not. I put all songs on my IPhone in a playlist, and when playing songs from it the problem continues to occur. However, the playlist is really large, >10k of songs.

I'll split it up. Should I happen to figure out the threshold, I'll post it here.