Contacts not showing up in car Bluetooth paring

[robotomo]

So my mum has a galaxy S4, and when she tries to connect it to her car (Toyota RAV4) via Bluetooth, none of her contacts come up. But when I tried connecting with my phone (HTC One M7) all of my contacts came up.
Are there any reasons for her contacts not showing up?

 

[B. Diddy]

On her phone, go to Settings>Bluetooth, tap the gear icon next to the car system, and make sure Contact Sharing is turned on.