Software engineering in the automotive domain faces outstanding challenges in terms of quality, cost, and functional complexity. To ensure process and product excellence, Bosch Gasoline Systems (GS) introduced a process improvement program based on Capability Maturity Model Integration (CMMI) and adopted the product line approach (PLA). Business strategies for software products, software sharing with customers, and common solutions for diesel and gasoline engine control software are inputs for the product line architecture. The steps towards the PLA started with an evaluation project followed by an evolutionary rollout. The lack of suitable mechanisms and tools for some crucial nonfunctional requirements is a major drawback for introducing the PLA. Nevertheless, GS considers it the only systematic approach to dealing with current and future challenges.