California Code, Vehicle Code - VEH § 11220

The department may require any person licensed under this chapter to submit to a reexamination of his or her qualifications when there is reasonable cause to believe that the licensee does not have the ability to give instruction.  If the licensee refuses or fails to submit to the reexamination, the department may, without a hearing, temporarily suspend his or her license until such time as the licensee submits to the reexamination.  The suspension shall be effective upon receipt of notice by the licensee.