Cal. Health & Safety Code § 18122.5

It is unlawful for any person to fail or neglect properly to endorse, date, and deliver the certificate of title and, when having possession, to fail to deliver the registration card to a transferee who is lawfully entitled to a transfer of registration. Except when the certificate of title is demanded in writing by a purchaser, a manufactured home, mobilehome, or commercial coach dealer licensed, as provided by this part, shall satisfy the delivery requirement of this section by submitting appropriate documents and fees to the department for transfer of registration in accordance with this part and rules and regulations promulgated thereunder.