The difference between a code of ethics and a code of conduct is often blurred in day to day usage, but there is a difference. Codes of conduct are derived from codes of ethics whether the ethical code is a written code or unwritten and understood by members of the organization developing the code.

Codes of Ethics

...

An ethical code in its formal sense is an attempt by an organization to codify the values of the group – a statement of overarching principle telling members what is right and what is wrong as a guide to all decision making within the organization. Codes of ethics set out general principles, often social or moral, that guide rather than dictate behavior.

Codes of Conduct

...

Codes of conduct are specific rules designed to outline specific practices and behaviors that are to be encouraged or prohibited under the ethical code of an organization or individual. Codes of conduct lay out guidelines and procedure to be used to determine whether violations of the code of ethics have occurred and delineate the consequences for such violations. Conduct codes govern things like conflicts of interest or acceptance of gifts and what penalties should be imposed for specific infractions.

Codes of Practice

...

Codes of conduct and codes of ethics are often confused with codes of practice. A code of practice is a document designed to provide a clear example of what is correct, ethical or right behavior in any circumstances. A code of practice generally implies that violation of these codes of practice can result in disbarment or expulsion from the organization.

Similarities

...

Codes of ethics and codes of conduct are designed to promote ethical behavior among members of a group or in an individual. Both help to identify what is acceptable behavior and what is not and to promote higher standards of behavior within the group. Both help establish a framework for evaluating the behavior of the individual or group member and both help identify those who subscribe to these codes as members of a specific group.

Differences

...

Ethical codes are focus on broader issues and are often framed as a belief statement regarding the organization’s mission, its values and expectations for its members. A conduct code is designed to translate the ethics code into specific do and don’t guidelines and to promote adherence to the code of ethics by providing specific examples of real world applications of the code of ethics. The code of ethics is very broad and theoretically can be used to guide decision-making in all areas of member behavior. A code of conduct only covers what specific incidents and situations the composers think to put into the code. Should behavior occur which is not covered under the conduct code, members would have to refer to the code of ethics in order to revise the code of conduct to cover the omitted behavior or situation.