Cal. Rev. & Tax. Code § 21020

For the purposes of Part 11 (commencing with Section 23001) of Division 2 only, a taxpayer shall not be suspended pursuant to Section 23301, 23301.5, or 23775 unless the board has mailed a notice preliminary to suspension which indicates that the taxpayer will be suspended by a date certain pursuant to Section 23301, 23301.5, or 23775, as the case may be. The notice preliminary to suspension shall be mailed to the taxpayer at least 60 days before the date certain.