While my Google Contacts sync from Google Contacts down to my iPhone, it failed to sync Contacts created on my iPhone back up to Google Contacts.
Solution:
Go to Settings > Mail, Contacts, Calendars > scroll down to the Contacts section > Default Account > Choose your Google CardDAV account.
One response to “iPhone: Google Contacts CardDav Sync Problem”
http://www.leawo.org/tutorial/how-to-transfer-contacts-from-mac-to-iphone.html