They officially dropped "Don't be evil" a long time ago.
If your master has no such Code of Conduct, then you have no such Code of Conduct when push comes to shove.
It's like "we value your privacy" or "all natural ingredients", it means nothing because you can define the terms anyway you like.
Defining meaning is really hard.
That's why English Common Law relies on precedence to fix details. "Codes of Conduct", mission statements and advertising are all just meaningless fluff because they are open to interpretation.