California Code, Civil Code - CIV § 2983.35

(a) If a creditor has requested a cosigner as a condition of granting credit to any person for the purpose of acquisition of a motor vehicle, the creditor or holder shall give the cosigner a written notice of delinquency prior to the repossession of the motor vehicle if the motor vehicle is to be repossessed pursuant to the motor vehicle credit agreement.  The written notice of delinquency shall be personally served or shall be sent by certified mail, return receipt requested, or first-class mail, postage prepaid, directed to the last known address of the cosigner.  If the last known address of the buyer and the cosigner are the same, a single written notice of delinquency given to both the borrower and cosigner prior to repossession satisfies the cosigner notice requirement of this section.

(b) A creditor or holder who fails to comply with this section may not recover any costs associated with the repossession of the vehicle from the cosigner.

(c) This section applies to any motor vehicle credit agreement, notwithstanding Section 2982.5.

(d) The following definitions govern the construction of this section.