Though everyone today remembers the Comic Code Authority and its Code of 1954, there was an earlier attempt at a self-regulating Code created in 1948 by the "Association of Comic Book Publishers," an industry organization put together by several comics publishers. This code didn't have much effect and several publishers soon dropped out of the group. Here is a link to the testimony of Henry Schulz, counsel for the ACBP, at the 1954 Senate Subcommittee hearings. It recounts the Association's history and includes a copy of its Code.
http://www.thecomicbooks.com/schultz.htmlComparing the Association's Code with comics bearing their seal suggests not all the members took it seriously. Along with Parent's Institute (whose publisher apparently founded the organization). signees included Gleason, Avon, Ace, Hillman, Superior and Orbit.