California is unique in that it is the only state, along with Maine, which has not adopted either the Model Code or the Model Rules. Instead, California has its own code of professional responsibility. These rules can be found at the California State Bar's website.
California professional responsibility law is divided between California Business and Professions Code Section 6068 (the statutory duties of an attorney), the California Rules of Professional Conduct, and a number of uncodified cases. A few of the CRPC rules have clearly been inspired by ABA rules, though. A number of innovations in professional responsibility law have first arisen in California, such as Cumis counsel.
Of all American states, California is notorious for imposing the strongest duty of confidentiality upon its attorneys. There were no exceptions to the rule until 2004, when Business & Professions Code Section 6068 was finally amended to add a single discretionary exception to prevent imminent death or great bodily harm. The amendment was clearly borrowed from the ABA Model Rules of Professional Conduct.