California Code, Probate Code - PROB § 9390

(a) An action to establish the decedent's liability for which the decedent was protected by insurance may be commenced or continued under Section 550, and a judgment in the action may be enforced against the insurer, without first filing a claim as provided in this part.

(b) Unless a claim is first made as provided in this part, an action to establish the decedent's liability for damages outside the limits or coverage of the insurance may not be commenced or continued under Section 550.

(c) If the insurer seeks reimbursement under the insurance contract for any liability of the decedent, including, but not limited to, deductible amounts in the insurance coverage and costs and attorney's fees for which the decedent is liable under the contract, an insurer defending an action under Section 550 shall file a claim as provided in this part. Failure to file a claim is a waiver of reimbursement under the insurance contract for any liability of the decedent.