What is the ethical code a PMP credential holder must adhere to?

The ethical code that a PMP credential holder must adhere to is the Project Management Institute (PMI) Code of Ethics and Professional Conduct. This code is based on the four core values of the project management profession: responsibility, respect, fairness, and honesty.
The PMI Code of Ethics and Professional Conduct is designed to guide project managers in making ethical decisions and to protect the public interest. It applies to all PMI members, volunteers, credential holders, and certification applicants.