Los Angeles Deputy District Attorney Alex Karnanen says the 48-year-old faces up to four years in prison as part of a plea deal.
Dykstra and two co-defendants are accused of trying to lease and then sell high-end cars from several car dealerships in January by claiming credit through a phony business.
In exchange for changing his plea, prosecutors dropped more than a dozen charges against Dykstra, shortening the possible jail time he faces by eight years.
He had initially entered the not guilty plea in January.
Dykstra is scheduled to be sentenced next Jan. 20.