CA Prob Code Section 8007

(a)

Except as provided in subdivision (b), an order admitting a will to probate or appointing a personal representative, when it becomes final, is a conclusive determination of the jurisdiction of the court and cannot be collaterally attacked.

(b)

Subdivision (a) does not apply in either of the following cases:

(1)

The presence of extrinsic fraud in the procurement of the court order.

(2)

The court order is based on the erroneous determination of the decedent’s death.