Cal. Code of Civil Procedure § 340.6

(a) An action against an attorney for a wrongful act or omission, other than for actual fraud, arising in the performance of professional services shall be commenced within one year after the plaintiff discovers, or through the use of reasonable diligence should have discovered, the facts constituting the wrongful act or omission, or four years from the date of the wrongful act or omission, whichever occurs first. If the plaintiff is required to establish the plaintiff’s factual innocence for an underlying criminal charge as an element of the plaintiff’s claim, the action shall be commenced within two years after the plaintiff achieves postconviction exoneration in the form of a final judicial disposition of the criminal case. Except for a claim for which the plaintiff is required to establish the plaintiff’s factual innocence, the time for commencement of legal action shall not exceed four years except that the period shall be tolled during the time that any of the following exist: (1) The plaintiff has not sustained actual injury. (2) The attorney continues to represent the plaintiff regarding the specific subject matter in which the alleged wrongful act or omission occurred. (3) The attorney willfully conceals the facts constituting the wrongful act or omission when those facts are known to the attorney, except that this subdivision shall toll only the four-year limitation. (4) The plaintiff is under a legal or physical disability that restricts the plaintiff’s ability to commence legal action. (5) A dispute between the lawyer and client concerning fees, costs, or both is pending resolution under Article 13 (commencing with Section 6200) of Chapter 4 of Division 3 of the Business and Professions Code. As used in this paragraph, “pending” means from the date a request for arbitration is filed until 30 days after receipt of notice of the award of the arbitrators, or receipt of notice that the arbitration is otherwise terminated, whichever occurs first. (b) In an action based upon an instrument in writing, the effective date of which depends upon some act or event of the future, the period of limitations provided for by this section shall commence to run upon the occurrence of that act or event.