billbak

For 18 months wireless CarPlay has worked flawlessly in my 2020 SQ7. Two days ago it abruptly quit. Then worked, then quit. By 'quit' I mean the main MMI screen lists 'Phone Apps' instead of CarPlay. Yesterday the same nonsense and today too. Works sometimes, not others. I have Audi Connect Prime. My phone is connected to the car via BT. It's generally connected to the car's 5G.

What's the CarPlay protocol, at a high level? Does it work over BT? Or BT with a switch to wi-fi? Can it work on BT only? I'm having a lot of trouble debugging this. If anyone can suggest an approach to debugging this, I will be very appreciative. Thanks in advance!

4ringsnewbie

WWDC 16 scroll down to Developing CarPlay Systems

billbak

Oh, you rock! Dang, I should have thought of that myself. I was at that WWDC. Thanks for the pointer!

FWIW, I found a reproducible way to get it to connect this afternoon. Not sure why anything changed this week, the phone and the car have not had any recent updates. Or more accurately, it worked fine since the last iOS update but then failed recently.

• Start the car.
• Wait for the signal that BT has connected, this is taking between three and five minutes now, it used to take far, far less time.
• Go into settings on the phone, wireless, pick the car's 5G connection. Get the error message, "Hotspot login cannot open the page because it could not establish a secure connection to the server." This is a big clue -- is there a cert somewhere that expired? Maybe the WWDC presentations will tell me about that.
• Press OK on the error message.
• Wait a few more minutes for the phone to connect to the car's hotspot. (I know, it said it can't but it does...)
• Then press the "Phone Apps" icon on the main MMI screen. That tells me I need to be connected to the car's hotspot.
• Press the "Goto connected devices" button. (I may have the exact wording of that wrong)
• Select my phone.
• CarPlay starts.

This worked several times in a row but takes upwards of five minutes. I'm going to dig into this secure (cert) issue...

itcsburnett

My biggest problem is with CarPlay, both wired and wireless, disconnecting, sending me back to MMI mode and then abruptly reconnecting (when I'm lucky)
Each time it does this of course the Sirius radio is stopped as it seems to select the CarPlay audio as default. IOS13 seemed to work better if i was wired, but since upgrading to IOS15, only wireless seems to offer a (slightly more_ stable connection.
Could be coincidence, but it seems if I start the car and then open the myAudi app on the phone and let it connect before shifting into gear, it is much more likely to stay connected. It HAS to be the Audi implementation of CarPlay as the very same phone has ZERO issues in my 2017 Subaru

DirkM

There have been various reports of wireless CarPlay issues if the phone gets connected to the car's WiFi hotspot. It's better to connect the phone via BT only and let it switch to its "private" WiFi connection for CarPlay. Once the phone is connected to the car's WiFi, it will always try to establish The WiFi link first before trying BT. That's why there may be more noticeable delays after starting the car.

Short of doing a factory reset on the MMI I would suggest the following:
- delete the phone from the car (both BT and WiFi clients)
- delete the car from the phone (both in BT as well as WiFi)
- connect the phone to the car via BT only, this will cause a prompt on the phone asking if you want to use this connection for CarPlay, confirm with ok or yes
- the phone will then establish a "private" WiFi connection to the MMI to use for CarPlay but the initial pairing after starting the car is done via BT

The main difference is that with an initial BT connection, your phone uses its data plan for Internet and not the car's.
If the initial connection is via WiFi, the phone will use the car's WiFi for Internet which will stop working without Audi Connect Prime (unless WiFi Assist is enabled in the phone).

Wires

I don't have CarPlay, but doing the 3-finger reboot of the MMI (holding the rockers up and pressing down on the ****) might help.

With wireless Android Auto on my other car, wifi signal strength had a huge impact. When I had my Samsung S10, if I left phone phone in my left pocket, it would connect, work a bit and drop. Placing the phone in the center console, then it worked flawlessly. You might want to check if it' a distance from the head unit issue.

SCarGuy

what IOS are you running?

carplay uses both bluetooth and wifi - it can't work without both enabled

itcsburnett

That seems to be the case with Audi anyway.
Following the advice above, i turned Wifi off on the phone before I got in. Started the car and saw that Bluetooth was connected. Went to connect Carplay and the MMI saw the phone, selected it. Got eh "Establishing Connection" but it never went to CarPlay. Re-enabled WiFi on the phone and did the same procedure and it did connect to carplay. I dont have any data plan in the car (didnt buy the nav option which i am now kicking myself for) so i dont understand why it needs to connect to the cars WiFi.

DirkM

It wants WiFi because the initial CarPlay setup was via WiFi. The only way out of the is to reset the MMI or to delete the car from the phone and phone from the car and start over.

Wires

As a FYI, CarPlay and Android Auto work similar from the connectivity standpoint (regardless of vendor). When your phone connects to the head unit via Bluetooth, the Bluetooth sends back a wifi-direct access point name + credentials. The phone then logs into the head unit Wi-Fi and the link is completed. At this point, Bluetooth is no longer used since it cannot support the data transfer rates required for these services. Bluetooth will remain connected to the car to allow for the handsfree calling to work through the car speaker/mic though.