According to the First Amendment Coalition, which answered a similar question in 2012:
Unlike the federal Freedom of Information Act, and other state public records laws, the California Public Records Act does not establish any system of administrative appeal, neither within the agency itself nor with any other body of the state government. Rather, the only way formally to challenge a determination that a record is exempt from the Public Records Act is to file a lawsuit. Cal. Govt. Code sections 6258, 6259.
Read more here. Procedures adopted by the California's DMV do not address appeals of agency responses to information requests. See DMV manual here. The First Amendment Project Society of Professional Journalists (Nor. Cal.) nonetheless suggests appealing if your request is denied. See pocket guide here.