California Penal Code 273.5 is not categorically a crime of moral turpitude, because it could be against a co-habitant. The Ninth has recently held in a published opinion, however, that the statute is divisible and resort can be had to the modified categorical analysis to determine whether the victim was such that the crime involved moral turpitude (e.g., a spouse), or did not (e.g., a cohabitant). See Vargas-Cervantes v. Holder (9th Cir. 2014) (273.5(a) divisible statute for CIMT). http://cdn.ca9.uscourts.gov/datastore/opinions/2014/11/19/10-73384.pdf

Note: this offense is categorically a crime of domestic violence per another decision of the Ninth Circuit. See Marquez-Carrillo v. Holder (9th Cir 2015) (Penal Code 273.5(a) categorically crime of domestic violence).
http://cdn.ca9.uscourts.gov/datastore/opinions/2015/03/31/12-70779.pdf