Section 8007 Of Chapter 1. Commencement Of Proceedings From California Probate Code >> Division 7. >> Part 2. >> Chapter 1.

. (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.