Cal. Rev. & Tax. Code § 19307

For purposes of Section 19306, a return filed within four years from the last day prescribed for filing the return showing a credit allowable by Section 19002 or estimated tax paid pursuant to Section 19023, 19024, or 19136 in excess of the tax due, shall be considered a claim for refund of the excess if the amount thereof is more than one dollar ($1). No refund of tax withheld or estimated tax paid shall be allowed to an employee or taxpayer who fails to file a return for the taxable year in respect of which the tax withheld or estimated tax was allowable as a credit.