Veh. Code, § 5901

(a) Every dealer or lessor-retailer, upon transferring by sale, lease, or otherwise any vehicle, whether new or used, of a type subject to registration under this code, shall, not later than the end of the fifth calendar day thereafter not counting the day of sale, give notice of the transfer to the department electronically in a manner approved by the department.

(b) Except as otherwise provided in this subdivision or in subdivision (c), the dealer or lessor-retailer shall enter on the form and pursuant to Section 32705(a) of Title 49 of the United States Code, on the ownership certificate, the actual mileage of the vehicle as indicated by the vehicle’s odometer at the time of the transfer. However, if the vehicle dealer or lessor-retailer has knowledge that the mileage displayed on the odometer is incorrect, the licensee shall indicate on the form on which the mileage is entered that the mileage registered by the odometer is incorrect. A vehicle dealer or lessor-retailer need not give the notice when selling or transferring a new unregistered vehicle to a dealer or lessor-retailer.

(c) When the dealer or lessor-retailer is not in possession of the vehicle that is sold or transferred, the person in physical possession of the vehicle shall give the information required by subdivision (b).

(d) A sale is deemed completed and consummated when the purchaser of the vehicle has paid the purchase price, or, in lieu thereof, has signed a purchase contract or security agreement, and has taken physical possession or delivery of the vehicle.

(e) This section shall become operative January 1, 2019.