From Acura HandsFreeLink:
Special instructions for pairing Samsung Phones (not all may be applicable to every phone)
SAMSUNG
Bluetooth Power
Ensure Bluetooth is turned ON permanently.
Discoverable/Visible
1. Go to Menu
2. Select Settings and/or Tools
3. Select Bluetooth
4. Select Settings/Visibility
5. Set Discovery Mode/Visibility to ON
Authorize Connection
1. Go to Menu
2. Select Settings and/or Tools
3. Select Bluetooth
4. Select HFL
5. Set Options to Authorize Device
Auto Answer
1. Go to Menu
2. Select Settings and/or Tools
3. Select Call Settings
4. Select Auto Answer or Answer Options
5. Set Auto Answer to OFF
Answer Options
1. Go to Menu
2. Select Settings and/or Tools
3. Select Call Settings (on some models, select Others, then Call Setup or Phone Settings, then Extra Settings)
4. Under Answer Options/Call Answer, select Flip/Slide, AnyKey, Send, or Auto Answer (if available).
Auto Answer is the preferred setting but any of these will work.
Setting discoverable to ON permanently makes a huge difference with a lot of phones, in my experience with the Acura HFL system.