I've been having an issue since I got my car in February. My iPhone 8+ will sync via bluetooth to the C-Max, but Siri is unusable. If I activate Siri it'll try listening, but won't actually hear me talking. I took my car to the dealership and got them to update the software(which was a waste of money because I could have done it myself), so I believe I should be running the latest software for my car. I see in this video the voice button should work, but it seems to only activate the nearly useless built-in Sync voice commands. I've tried holding onto the voice button for short presses, long multi-second presses and it still doesn't want to activate Siri.