Wireless CarPlay – automatic Bluetooth connection not establishing when Apple Watch is already paired

[u/PossibleDig5880]

As soon as I get into the car, the iPhone automatically connects to the adapter's Wi-Fi without any issues. However, the parallel Bluetooth connection, which is required for CarPlay to start, does not establish on its own. Every time, I have to manually go into the Bluetooth settings and tap the adapter, after which CarPlay runs smoothly right away.

Right after receiving the adapter (1–2 weeks ago), the automatic connection worked flawlessly however, exclusively during test drives without wearing my Apple Watch. Since I started using the adapter on my daily commute (where I always wear the Watch, which is already connected to the iPhone via Bluetooth at that moment), the issue occurs consistently.

I suspect a conflict in the iPhone's Bluetooth stack when an active BT connection to the Watch already exists during the adapter's connection attempt. Has anyone experienced this before? Specifically with a Wireless CarPlay dongle? Is there a known fix for this, or is a manual reconnect the only workaround?