How to prevent iPhone 16 Pro from switching to car's Wi-Fi network during wireless CarPlay?

Disable Auto-Join for the Car's Wi-Fi

This tells your iPhone not to use the car's Wi-Fi for internet, while still allowing CarPlay to function.

1. Get in the car and connect to CarPlay.
2. Go to Settings > Wi-Fi on your iPhone.
3. Tap the "i" icon next to your Car's Wi-Fi network.
4. Turn off "Auto-Join".
5. Do not forget the network — just disable auto-join.

This lets the phone maintain the Wi-Fi link for CarPlay’s needs without using it for internet.

Also check Settings > Cellular > Wi-Fi Assist and make sure it's turned on — this allows the phone to switch back to cellular when Wi-Fi is flaky.

Something unusual happened that caused you to connect to the vehicle's wi-fi network. It shouldn't be connected to that, it is connected to a different wi-fi for wireless CarPlay. On the iPhone, go to Settings>Wi-Fi and forget the wi-fi network for your vehicle. Now, go to Settings>General>CarPlay, and remove the vehicle from the list of CarPlay devices. Also go to Settings>Bluetooth and remove your vehicle as well. Power cycle the car and the iPhone. We are going to set it up all over again.

Now, go back to Settings>General>CarPlay. You should see some instructions under the image about setting up for wireless CarPlay. Press and hold the voice control button on your vehicle and hold it until you see instructions on the vehicle and the phone. You should be prompted to verify a pin number to show the car and phone are looking at the other. Then you should see a pair button. While the car will show up in the list on the car when this is done, you will be connected to wireless CarPlay, but you should not see the wi-fi fan in the status bar. You do not want to use the car's wi-fi internet. It will use the iPhone's cellular data for things. This happened to my car before when they tried to get me to use the car's data with a free trial, and it messed everything up. I just had to delete all of the car/phone connections and start over again. This should fix it up for you.

TestTickle wrote:

But wouldn’t this prevent Carplay from working since it needs Wifi?

No. I have never enabled in car Wifi in my 2025 car, which offers the option. Wireless CarPlay works just fine.

Disable the car's wifi network on the head unit.

KiltedTim wrote:

Disable the car's wifi network on the head unit.

That would be my advice as well.

I just started having a similar issue about a week ago, except it only happens for me when the phone initially connects to Carplay. Turning my wifi off and then on again on my phone fixes it, which is confusing me.

It has worked fine for over a year, so I don’t know if it was an iOS update or what (I’m on 18.5).

TestTickle wrote:

lobsterghost1 wrote:

No. I have never enabled in car Wifi in my 2025 car, which offers the option. Wireless CarPlay works just fine.

So you are telling me that your phone is not connected to your vehicle’s Wifi at all? I have to be connected to mine for Wireless Carplay to work. Disconnecting from the vehicle’s Wifi disables Carplay and Bluetooth takes over.

In my 2024 Colorado, I don’t think there’s an option to turn off the Wifi anyway. There is an option to allow connected devices to use the vehicle’s data, which is and has always been disabled, but that’s it.

It just makes no sense to me that I have had the vehicle for over a year and this literally just started happening. My best guess is that it was an iOS update, but that’s just a guess at this point.

No, I'm not connected to my cars Wifi, nor is it a requirement for wireless CarPlay. CarPlay uses your phone's cellular connection. And it also connects via Bluetooth. Your cars Wifi shouldn't be used for CarPlay at all. ChrisJ4203, provided a more thorough response, so follow his directions.

It depends on the headunit. I have one that recently started doing the exact same thing you've been experiencing even though it worked fine for 2 years. I noticed that on some occasion the phone will ask if you want to switch to cellular which does the same thing as toggling wifi on/off. Not really a great workaround because I prefer not to have to take my phone out of my pocket at all. Sometimes it will function properly but I'm not sure what is triggering it. In our other car with wireless CarPlay it doesn't happen. Different units but same phones/iOS (18.5).

It depends on the headunit. I have one that recently started doing the exact same thing you've been experiencing even though it worked fine for 2 years. I noticed that on some occasion the phone will ask if you want to switch to cellular which does the same thing as toggling wifi on/off. Not really a great workaround because I prefer not to have to take my phone out of my pocket at all. Sometimes it will function properly but I'm not sure what is triggering it. In our other car with wireless CarPlay it doesn't happen. Different units but same phones/iOS (18.5).

Exactly. My Colorado absolutely requires Wifi to be on for CarPlay to work. Turning off Wifi disables CarPlay.

Update on my particular issue though, I had this problem for about a week or so, and it suddenly started working like normal out of nowhere. I did nothing and nothing changed, it just started working again. Weird.

depends on the headunit. I have one that recently started doing the exact same thing you've been experiencing even though it worked fine for 2 years. I noticed that on some occasion the phone will ask if you want to switch to cellular which does the same thing as toggling wifi on/off. Not really a great workaround because I prefer not to have to take my phone out of my pocket at all. Sometimes it will function properly but I'm not sure what is triggering it. In our other car with wireless CarPlay it doesn't happen. Different units but same phones/iOS (18.5).

I am pretty sure Auto-Join refers to joining a Wifi network, not specifically connecting to the Internet. It simply forces the user to manually connect.

I tried this on my phone and it didn’t connect to Carplay at all until I manually connected.

lobsterghost1 wrote:

No. I have never enabled in car Wifi in my 2025 car, which offers the option. Wireless CarPlay works just fine.

So you are telling me that your phone is not connected to your vehicle’s Wifi at all? I have to be connected to mine for Wireless Carplay to work. Disconnecting from the vehicle’s Wifi disables Carplay and Bluetooth takes over.

In my 2024 Colorado, I don’t think there’s an option to turn off the Wifi anyway. There is an option to allow connected devices to use the vehicle’s data, which is and has always been disabled, but that’s it.

It just makes no sense to me that I have had the vehicle for over a year and this literally just started happening. My best guess is that it was an iOS update, but that’s just a guess at this point.

robotphood wrote:

Some headunits connect to the phone through wifi for CarPlay. It literally won't work if you turn off wifi.

Perhaps some do. I certainly haven't owned any car where Wifi was required for CarPlay, however. The last three car brands I've owned which had Apple CarPlay were (not necessarily in order of ownership), Genesis, Mercedes, Mazda. None of which required Wifi.

But wouldn’t this prevent Carplay from working since it needs Wifi?

Some headunits connect to the phone through wifi for CarPlay. It literally won't work if you turn off wifi.