brother scanner

When networked (wired/wireless) the 9340cdw is supported by Apple's built-in AirPrint and needs no Brother driver downloads. I suggest with the device powered and networked, that you remove it from System Preferences > Printers & Scanners with the [-] button, and when the Bonjour discovery panel next appears, select the 9340cdw discovery entry. This will activate the Use: selector which may settle on Default, or AirPrint — both meaning the same thing. Then click Add.

If the 9340cdw is not immediately accessible to Apple's Image Capture, there may be controls on the Printers & Scanners panel for this device to further configure scanning support and then use Image Capture.

The Brother iPrint&Scan in the App Store I find is often more able to manage the scanning functions of the multifunction printers from Brother. Try downloading that software and see if it works any better.

Check with Brother to see if they have an “ICA” driver or scanning update.