California Vehicle Code section 23612
(h) A preliminary alcohol screening test that indicates the presence or concentration of alcohol based on a breath sample in order to establish reasonable cause to believe the person was driving a vehicle in violation of Section 23140, 23152, or 23153 is a field sobriety test and may be used by an officer as a further investigative tool.
(i) If the officer decides to use a preliminary alcohol screening test, the officer shall advise the person that he or she is requesting that person to take a preliminary alcohol screening test to assist the officer in determining if that person is under the influence of alcohol or drugs, or a combination of alcohol and drugs.
The person’s obligation to submit to a blood, breath, or urine test, as required by this section, for the purpose of determining the alcohol or drug content of that person’s blood, is not satisfied by the person submitting to a preliminary alcohol screening test.
The officer shall advise the person of that fact and of the person’s right to refuse to take the preliminary alcohol screening test.