As technological advancements progress, the automotive industry is getting closer to producing Level 4 connected and automated vehicles (CAVs). Market trends show personal vehicle sales moving towards sport utility vehicles (SUVs) and increasing use of ridesharing services. We conducted a life cycle assessment (LCA) of Level 4 CAV subsystem components integrated into battery electric vehicle (BEV SUV) and internal combustion engine vehicle (ICEV van) platforms to understand the impact of the components and automation on greenhouse gas (GHG) and primary energy use. Vehicle lifetime was modeled based on deployment as an automated taxi, incorporating a standby mode to account for continuous connectivity. This study explores impacts of weight, drag, and subsystem electricity demand relative to benefits of eco-driving, platooning, and intersection connectivity at the vehicle system level. A CAV BEV coupled with a low carbon intensity grid (0.08 kg CO2e/kWh) could see a 31% decrease in life cycle GHG emissions while a CAV BEV with high computing power requirements (4000 W) could see an increase in GHG emissions of 34% compared with the base case. The net result for the base case (500 W computer power, 14% operational efficiency improvement, 45% highway driving) CAV shows an increase in primary energy use and GHG emissions (2.7%, 2.7% for BEV; 1.3%, 1.1% for ICEV) compared with non-CAV platforms.