CA Civ Proc Code Section 1141.17

(a)

Submission of an action to arbitration pursuant to this chapter shall not suspend the running of the time periods specified in Chapter 1.5 (commencing with Section 583.110) of Title 8 of Part 2, except as provided in this section.

(b)

If an action is or remains submitted to arbitration pursuant to this chapter more than four years and six months after the plaintiff has filed the action, then the time beginning on the date four years and six months after the plaintiff has filed the action and ending on the date on which a request for a de novo trial is filed under Section 1141.20 shall not be included in computing the five-year period specified in Section 583.310.