Health and Safety Code § 43643

Any motor vehicle equipped with a certified device shall not be deemed in violation of the provisions of this part, or Section 27156 of the Vehicle Code, because the certification of the device is subsequently revoked, suspended, or restricted.

Replacement parts for the device may continue to be supplied and used for such vehicle, unless the revocation, suspension, or restriction is based upon a finding that the certified device has been found to be unsafe in actual use or is otherwise mechanically defective, in which event the device shall be brought into compliance with the provisions of this part within 30 days after such a finding.